NUTRITION EDUCATION SERIES

ISSUE 9

NUTRITION AND EDUCATIONAL ACHIEVEMENT

by

Ernesto P o l l i t t , P1i.D.

N u t r i t i o n Educat ion Programme D i v i s i o n o f Science, Technica l and Vocat ional Educat ion

U n i t e d Nat ions Educat ional , S c i e n t i f i c and C u l t u r a l Organizat ion

c

Par i s , 1984 ED-84/WS/66

TABLE OF CONTENTS

Preface ............................................................... INTRODUCTION .......................................................... I . II .

III .

I V .

V .

Determinants o f School ing ........................................ E f f e c t s of M a l n u t s i t i o n i n In fancy and t h e Pre-school Pe r iod on School Achievement and I n t e l l e c t u a l Func t ion .................. N u t r i t i o n a l Status. School Achievement and I n t e l l e c t u a l Func t ion ......................................................... N u t r i t i o n I n t e r v e n t i o n . School Achievement and I n t e l l e c t u a l Func t ion ......................................................... Conclusions ......................................................

APPENDIX .............................................................. Tab le 1 . E a r l y N u t r i t i o n a l S ta tus and E f f e c t s on School

Achievement and I n t e l l e c t u a l Func t ion .................. Tab le 2 . Cur ren t N u t r i t i o n a l S ta tus and E f f e c t s on School

Achievement and I n t e l l e c t u a l Func t ion .................. Table 3 . N u t r i t i o n I n t e r v e n t i o n and E f f e c t s on School

Achievement and I n t e l l e c t u a l Func t i on ..................

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PREFACE

The s c i e n t i f i c evidence presented i n t h i s monograph shows t h a t m a l n u t r i t i o n i n i n f a n t s and c h i l d r e n i s a r i s k f a c t o r i n t h e fo rma l educat iona l system. The conclus ions advanced i n d i c a t e that i t i s impor tan t t o i nc lude n u t r i t i o n as a determinant of school performance and achievement. n u t r i t i o n a l s ta tus among school c h i l d r e n has s i g n i f i c a n t adverse e f f e c t s on school progress. i n a count ry and the c o n t r i b u t i o n by malnour ished c h i l d r e n t o educat iona l wastage. Ch i l d ren who a r e undernour ished and whose l e a r n i n g i s s l o w have d i f f i c u l t i e s master ing school m a t e r i a l and a re among those w i t h high chances o f repea t ing grades and dropping o u t e a r l y f rom school.

E a r l y m a l n u t r i t i o n o r poor

There i s a d i r e c t r e l a t i o n s h i p between t h e prevalence o f m a l n u t r i t i o n

D r P o l l i t t , a Peruvian, i s a world-renowned n u t r i t i o n and c h i l d development s p e c i a l i s t . Sciences Program a t t h e School o f P u b l i c Heal th , The U n i v e r s i t y o f Texas Hea l th Science Center a t Houston, D r P o l l i t t has h imse l f conducted many o f t h e impor tan t s c i e n t i f i c s tud ies i n t h e area o f n u t r i t i o n , c h i l d development and educat iona l performance.

C u r r e n t l y Professor o f N u t r i t i o n and Convener o f t h e Behav io ra l

Th is monograph has been prepared as par t o f t h e Unesco N u t r i t i o n Educat ion Programme w i t h p a r t i a l funding support f rom the U n i t f o r Co-operation w i t h UNICEF & WFP, Unesco, Par is .

The ideas and op in ions expressed i n t h i s monograph are those o f t h e author and do n o t necessa r i l y represent t h e views o f Unesco. p resen ta t i on o f m a t e r i a l s throughout the monograph do n o t i m p l y t h e express ion o f any op in ion whatsoever on t h e p a r t o f Unesco concerning t h e l e g a l s ta tus o f any country, t e r r i t o r y ' c i t y o r area o f i t s a u t h o r i t y o r concerning i t s f r o n t i e r s and boundaries.

The des ignat ions employed and t h e

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INTRODUCTION

Th is monograph presents a subs tan t ive but s e l e c t i v e rev iew o f t he l i t e r a t u r e on the e f f e c t s o f n u t r i t i o n and m a l n u t r i t i o n on educat iona l achievement. I t prov ides an i n t e r p r e t i v e c r i t i q u e o f the s tud ies reviewed and focuses on th ree areas:

(1) t h e e f f e c t s o f e a r l y u n d e r n u t r i t i o n and subsequent i n t e l l e c t u a l f u n c t i o n and school progress;

( 2 ) t h e r e l a t i o n s h i p between the n u t r i t i o n a l s t a t u s o f t he s tudent and school progress; and

(3 ) t h e educat iona l consequences o f n u t r i t i o n i n t e r v e n t i o n programmes, such as school feeding.

Ser ious methodologica l shortcomings i n many s tud ies i n t h i s area o f n u t r i t i o n and educat ion c loud t h e s i g n i f i c a n c e o f f i nd ings . However, when da ta i s poo led and analysed together c e r t a i n conclus ions a re j u s t i f i e d .

In ferences a r e the re fo re made rega rd ing the s i g n i f i c a n c e o f n u t r i t i o n as determinant of school progress and achievement. Some i m p l i c a t i o n s f o r n u t r i t i o n and educat ional p o l i c i e s a re a l s o made based on t h e da ta reviewed. A bas i c p r o p o s i t i o n o f t h i s monograph i s t h a t n u t r i t i o n , i n p a r t i c u l a r , and hea l th , i n general , need t o be considered as key determinants o f school progress and achievement, and tha t they are amenable t o changes through r e l e v a n t s o c i a l and educat iona l p o l i c i e s .

Fu r the r d e t a i l s on t h e s tud ies d iscussed can be found i n t h e summary t a b l e s o f t he Appendix. Readers i n t e r e s t e d i n o b t a i n i n g an e d i t e d s e t o f t he papers mentioned can w r i t e d i r e c t l y t o the Unesco N u t r i t i o n Educat ion Programme.

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I. DETERMINANTS O F SCHOOLING

School ing as a fo rma l educat iona l system i s one o f t h e most p o t e n t s o c i a l i z i n g agents t o which many i n d i v i d u a l s a re exposed. It has b e n e f i c i a l e f f e c t s on psycho- s o c i a l development and on t h e a c q u i s i t i o n and u t i l i z a t i o n o f knowledge, c o n t r i b u t i n g t o the economic and s o c i a l development o f i n d i v i d u a l s and soc ie ty , b o t h i n developed and developing count r ies . S i g n i f i c a n t p o s i t i v e assoc ia t ions have been repo r ted between education, persona l income, and occupat iona l l e v e l ( B e i r n , e t . a l . 1972; Simmons andaexander, 1975). Per c a p i t a growth f rom t h e gross n a t i o n a l p roduc t o f a count ry and the pe r cen t o f t h e p o p u l a t i o n o f school age e n r o l l e d i n t h e secondary l e v e l o f educat ion have a l s o been s t a t i s t i c a l l y assoc iated (Razin, 1977). I n f a c t , t he genera l d i r e c t i o n o f t h e a v a i l a b l e in fo rmat ion , desp i te a few c o n t r o v e r s i a l f i nd ings , support the conc lus ion t h a t schoo l ing i s an ins t rument o f i n d i v i d u a l and s o c i a l change, i nc reas ing the p r o b a b i l i t i e s o f genera l wel l -be ing.

There i s a subs tan t ive body o f l i t e r a t u r e on determinants o f school enro l lment , attendance and achievement. W i t h i n t h i s l i t e r a t u r e heavy emphasis has been g i ven t o s o c i a l and economic f a c t o r s i n t h e fam i l y , and t o t h e q u a l i t y o f school ing. I n general , these can be c l a s s i f i e d i n t o endogenous and exogenous determinants t o t h e c h i l d and t h e fam i l y .

N u t r i t i o n i s an endogenous f a c t o r t h a t a f f e c t s l e a r n i n g a b i l i t y and s k i l l s be fo re and a f t e r t h e c h i l d i s i n school. However, b o t h w i t h i n t h e n u t r i t i o n a l and educat iona l l i t e r a t u r e , n u t r i t i o n has rece ived l i t t l e a t t e n t i o n as a determinant o f school progress. Yet, as t h i s monograph w i l l show, the re i s da ta t h a t c l e a r l y shows t h a t m a l n u t r i t i o n i n i n f a n t s and c h i l d r e n i s a p o t e n t c o n t r i b u t o r t o school wastage. Before d iscuss ing t h e s p e c i f i c i ssue o f n u t r i t i o n as a determinant o f school progress a genera l d iscuss ion on school determinants i s presented.

Endogenous f a c t o r s

What a c h i l d can do b o t h p h y s i c a l l y and i n t e l l e c t u a l l y , as a r e s u l t o f n a t i v e endowment and developmental h i s t o r y a re endogenous f a c t o r s g e n e r a l l y c l a s s i f i e d as ap t i tudes . Learn ing a b i l i t y f o r example r e f l e c t s i n p a r t t h e c h i l d ' s s c h o l a s t i c ap t i tude. L ikewise, soc ia l -emot ional c h a r a c t e r i s t i c s r e f l e c t e d i n the c h i l d ' s independence, achievement mot iva t ion , s e l f r e l i a n c e , impulse c o n t r o l , and s t a b i l i t y , among o ther p e r s o n a l i t y c h a r a c t e r i s t i c s a r e endogenous f a c t o r s c l a s s i f i e d as a t t i t u d e s . Ap t i t ude and a t t i t u d e s , however, a re n o t o n l y input o r determinants o f school ing, but outcomes as w e l l . I n t h i s regard, l e a r n i n g how t o l e a r n i s one o f t h e most d i r e c t ways i n which schoo l ing shapes t h e ap t i t udes o f ch i l d ren .

The educat ion o f t h e parents , t he income o f t h e fam i l y , t he c h i l d ' s ca re tak ing arrangement, h i s h e a l t h and d i e t a r y i n take , a r e a l s o endogenous f a c t o r s t h a t determine i n p a r t the c h i l d ' s schoo l ing and performance. D i r e c t e f f e c t s a re dramat ic whenever the f i n a n c i a l s i t u a t i o n o f t h e family, o r t h e c h i l d ' s poor hea l th , impedes h i m con t inu ing school ing. t he ch i1d"s ap t i t udes and a t t i t u d e s rega rd ing school progress and achievement i l l u s - t r a t e i n d i r e c t e f f e c t s .

The f a m i l y ' s r e a r i n g and) s o c i a l i z a t i o n p r a c t i c e s which shape

Genera l ly t h e r e a r e c lose and causa l r e l a t i o n s h i p s among endogenous fac to rs . For instance, i n some s o c i e t i e s the f a m i l y ' s s t r u c t u r e ( i . e . s i z e ) determine the care tak ing arrangements, which i n turn w i l l i n f l u e n c e the c h i l d ' s t ime i n the school, o r even the c h i l d ' s educat iona l achievement. I n some coun t r i es i n A f r i c a and L a t i n America economic investments i n the educat ion o f c h i l d r e n w i t h i n a f a m i l y a re r e l a t e d t o b i r t h order . Parents i n low income segments o f d i f f e r e n t popu la t i ons have been repo r ted t o make l a r g e r f i n a n c i a l investments i n t h e educat ion o f t h e o l d e r s i b l i n g s , w i t h t he expec ta t ion o f e s t a b l i s h i n g a s i b l i n g educat iona l cha in ( O k e i j i d i e t a l .

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1976; B i r d s a l l , 1980). S i m i l a r l y , t h e s i z e o f t h e fami ly , the educat ion o f t he parents , and t h e na tu re o f t h e v e r b a l communication w i t h i n t h e household, determine o p p o r t u n i t i e s f o r learn ing , and t h e development o f achievement o r i e n t a t i o n (Deere, e t a l . 1982). Apt i tudes and a t t i t u d e s are the re fo re shaped, and t h e h i s t o r y o f t h e c h i l d i n school i s p a r t l y s e t by t h e f a m i l y ' s h i s t o r y and the l e a r n i n g environment i t prov ides.

Exogenous f a c t o r s

The q u a l i t y o f school ing, t h e t r a i n i n g o f t he teachers, t h e a v a i l a b i l i t y o f books and o the r educat iona l m a t e r i a l s exempl i fy exogenous f a c t o r s t h a t i n f l u e n c e the q u a l i t y o f t h e fo rmal educat iona l process. They determine t o a l a r g e e x t e n t t h e na tu re o f t h e f i n a l outcome: t h a t i s , t he a b i l i t i e s and a t t i t u d e s t h a t a s tudent w i l l possess i n order t o cope w i t h t h e demands o f t h e s o c i a l system. Decis ions about these key exogenous f a c t o r s , however, genera l l y f a l l ou ts ide the f a m i l y ' s i n f l uence , p a r t i c u l a r l y among low income segments o f t h e popu la t i on i n developing count r ies . Budgetary a l l o c a t i o n s o f r e g i o n a l o r c e n t r a l governments t o t h e educa- t i o n a l sec tor determine t h e q u a l i t y of school ing and s e t l i m i t s t o a s tudent 's academic progress. These a l l o c a t i o n s d e f i n e t h e s o c i a l and educat iona l p o l i c i e s o f governments and represents t h e i r commitment t o the fo rmat ion o f human resources and human c a p i t a l . One element which con t r i bu tes t o determine how such a l l o c a t i o n s meet t h e edua t iona l needs i s t h e a v a i l a b i l i t y o f i n fo rma t ion on t h e determinants o f school ing, and how schoo l ing shapes t h e a b i l i t i e s and s k i l l s r e q u i r e d by t h e s o c i a l system.

Endogenous and exogenous f a c t o r s a re n o t independent o f each other . I n many developing and even developed c o u n t r i e s c h i l d r e n exposed t o f a m i l y cond i t i ons conducive t o s c h o l a s t i c achievement a r e e n r o l l e d i n schools t h a t promote t h e acqui- s i t i o n o f c o g n i t i v e and s o c i a l s k i l l s and a b i l i t i e s which a re needed by, and rewarded economical ly i n soc ie ty . A t t he o the r s ide o f t he s o c i a l spectrum, c h i l d r e n o f paren ts who a re e i t h e r i l l i t e r a t e o r have n o t completed pr imary school ing o f t e n go t o schools where p u p i l s f rom two o r more grades share t h e same room and the same teacher. Books a re genera l l y n o t ava i l ab le , and the teachers have had l i m i t e d pedagogica l t r a i n i n g . These educat iona l experiences lower t h e p r o b a b i l i t i e s o f economic success o f c h i l d r e n i n developing countr ies, p a r t i c u l a r l y among those socie- t i e s undergoing f a s t s o c i a l and economic change.

A d i s t i n c t i o n between endogenous and exogenous f a c t o r s that shape a p t i t u d e and a t t i t u d e be fo re and a f t e r the c h i l d i s e n r o l l e d i n fo rma l educat ion i s a n a l y t i c a l l y use fu l . The pre-school c h i l d develops a r e p e r t o i r e o f behaviours and psycho log ica l t r a i t s t h a t determine i n p a r t t h e i n i t i a l response t o schoo l ing and subsequent academic progress. These t r a i t s r e s u l t f rom n a t i v e a b i l i t y and e a r l y developmental h i s t o r y . For example, exposure t o so-ca l led i n f a n t o r pre-school s t i m u l a t i o n pro- grammes con t r i bu tes t o the c h i l d ' s performance i n pr imary and even secondary schoo l ing (Consortium f o r L o n g i t u d i n a l Studies, 1983; I n t e r n a t i o n a l Development Research Centre, 1983). L ikewise, maternal ca re tak ing behaviours, such as frequency and q u a l i t y o f v e r b a l communication, e f f e c t t he pre-school c h i l d ' s language s k i l l s , which i n turn i n f l u e n c e school performance.

The e f f e c t s o f b o t h endogenous and exogenous f a c t o r s a re a l s o observed a f t e r t h e c h i l d i s e n r o l l e d i n school. There i s , f o r example, subs tan t ive evidence showing how t h e c h a r a c t e r i s t i c s o f t h e f a m i l y , o r t he educat iona l l e v e l o f t he parents, w i l l a f f e c t t h e c h i l d ' s school progress. As a l ready noted, these e f f e c t s a re d i r e c t , such as when they determine the c h i l d ' s e a r l y departure f rom t h e school system, o r i n d i r e c t , l i k e i n those cases where they shape the c h i l d ' s p u r s u i t o f academic achievements ( I r w i n , e t a l . 1978).

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Apt i tudes and a t t i t u d e s a re suscept ib le t o major changes during educat iona l process. There are complex i n t e r a c t i o n s among exogenous and endogenous f a c t o r s t h a t a f f e c t t he c h i l d ' s development during t h e pre-school and school age per iod . Pre-school c h i l d r e n w i t h good i n t e l l e c t u a l endowment and exposed t o f a m i l y env i ron- ments conducive t o l e a r n i n g may be handicapped i f t h e i r schoo l ing i s poor. Conversely, an e f f e c t i v e school system may compensate f o r f a m i l y de f i c ienc ies . By t h e same token, t he re w i l l be an adverse s y n e r g i s t i c i n t e r a c t i o n i n those cases where t h e i n i t i a l developmental experiences o f t he c h i l d a re poor and the school system i s i n e f f e c t i v e .

I n summary, f o r m a l educat ion represents a l o n g and complex process which i s m u l t i f a c t o r i a l l y determined. Enrolment, at tendance and achievement a r e determined by a se r ies o f f a c t o r s t h a t f a l l w i t h i n as w e l l as ou ts ide t h e c h i l d and the f a m i l y system. The i n f l u e n c e o f these f a c t o r s , f rom i n f a n c y through the school-age per iod , f a c i l i t i a t e o r h inde r the development o f n a t i v e a b i l i t i e s and s k i l l s . Moreover, f a c t o r s t h a t i n f l u e n c e t h e educat iona l process i n the same d i r e c t i o n tend t o be associated t o each o ther . Thus, p o v e r t y i n t h e family w i l l be coupled w i t h poor schools which r a r e l y p rov ide t h e l e a r n i n g experiences conducive t o t h e a c q u i s i t i o n o f those menta l a b i l i t i e s and l e a r n i n g s k i l l s necessary w i t h i n soc ie ty .

N u t r i t i o n as a determinant o f schoo l ing

I n comparison t o s tud ies on t h e s o c i a l and econornic determinants o f school ing, t he re i s a s c a r c i t y o f i n f o r m a t i o n on the e f f e c t s t h a t n u t r i t i o n and h e a l t h have on school enrolment and academic progress. Conceivably, t h i s l a c k o f i n f o r m a t i o n has con t r i bu ted t o t h e l i t t l e a t t e n t i o n g i ven by educat iona l p o l i c i e s i n most coun t r i es i n the wor ld t o t h e n u t r i t i o n a l and h e a l t h s t a t u s o f t he students.

I n developed coun t r i es the re genera l l y i s a low prevalence o f u n d e r n u t r i t i o n , o f s p e c i f i c n u t r i t i o n a l de f i c ienc ies , and o f d isease cond i t i ons which p lace a t r i s k the school progress o f c h i l d r e n and a re major causes o f p u b l i c h e a l t h concern. I n developing count r ies - p a r t i c u l a r l y among t h e low income segments o f popu la t i ons - i n f e c t i o n s and m a l n u t r i t i o n a re o f t e n endemic. Among them t h e prevalence of p r o t e i n - energy m a l n u t r i t i o n (PEM), and m i c r o n u t r t e n t d e f i c i e n c i e s ( i n c l u d i n g v i tamins and minerals! , i s genera l l y extremely high ( P e l l e t , 1983). G a s t r o i n t e s t i n a l and upper r e s p i r a t o r y i n f e c t i o n s have high frequency o f occurence, i nc reas ing the r i s k o f m a l n u t r i t i o n and m o r t a l i t y (Ashworth, 1982; Chen & Scrimshaw, 1983). Accord ing ly , i n these coun t r i es m a l n u t r i t i o n , as a r i s k f a c t o r f o r t he educat iona l f u t u r e o f i n f a n t s and ch i l d ren , should be a major concern f o r hea l th , n u t r i t i o n and educat iona l p o l i c i e s .

The high prevalence o f m a l n u t r i t i o n among infan- and young c h i l d r e n has ser ious developmental imp l i ca t i ons , because these age pe r iods a re c r i t i c a l i n the growth and development o f ch i l d ren . Basic ap t i t udes and a t t i t u d e s a r e shaped i n i n f a n c y and e a r l y childhood; moreover, during these developmental pe r iods the re i s a high demand f o r energy t o meet b i o l o g i c a l and s o c i a l chal lenges o f growth and maturat ion. L ike- wise the socio-economic contex t o f m a l n u t r i t i o n becomes p a r t i c u l a r l y r e l e v a n t when i t i s seen i n t h e l i g h t o f what i s c u r r e n t l y known on environmental determinants o f psychob io log ica l development. Ch i l d ren w i t h a h i s t o r y o f m a l n u t r i t i o n a re g e n e r a l l y bo rn i n t o f a m i l i e s w i t h t he lowest income, and w i t h t h e lowest l e v e l s o f educat ion as compared t o o the r f a m i l i e s w i t h i n t he same community. Th i s environmental con tex t can accentuate the adverse e f f e c t s o f t he n u t r i t i o n a l d e f i c i e n c i e s and v i c e versa.

As c h i l d r e n grow o l d e r b i o l o g i c a l ma tu ra t i on tends t o move them - as i n a l l l i v i n g organisms - towards a normal course o f development. I n o the r words, adverse developmental e f f e c t s from e a r l y trauma may be r e v e r s i b l e w i b h matura t ion i f the c h i l d i s exposed t o a s a l u t a r y s o c i a l environment. However, the environmental

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cond i t i ons i n which malnour ished c h i l d r e n genera l l y l i v e may prec lude t h i s process of r e o r i e n t a t i o n . The socio-economic cond i t i ons o f t h e family and the b i o p h y s i c a l environment t o which these c h i l d r e n are exposed i s f a r f rom sa lu ta ry . Moreover, these adverse environmental cond i t i ons genera l l y do n o t undergo any s i g n i f i c a n t change as t h e c h i l d grows o lder . Th i s c o n t i n u i t y works aga ins t re - rou t i ng t h e deve- lopment o f c h i l d r e n w i t h a h i s t o r y o f m a l n u t r i t i o n towards a normal path.

N u t r i t i o n a l d e f i c i e n c i e s

A b r i e f d e s c r i p t i o n o f p r o t e i n - energymalnu t r i t ion , i ron de f i c iency , v i t a m i n A de f i c iency , and i o d i n e d e f i c i e n c y fo l lows. O u t o f these f o u r types o f m a l n u t r i t i o n the f i r s t t h r e e are highly p r e v a l e n t i n many developing count r ies . I o d i n e d e f i c i e n c y e x i s t s throughoutmanyregions i n t h e w o r l d , but has a more r e s t r i c t e d geographica l d i s t r i b u t i o n as compared t o p ro te in -energyma lnu t r i t i on , vitamin A and i r o n de f i c iency . These f o u r types o f m a l n u t r i t i o n can a f f e c t t h e behav ioura l development and adapta- t i o n o f ch i l d ren . However t h e s tud ies reviewed are r e s t r i c t e d t o p r o t e i n - energy m a l n u t r i t i o n , hunger and i r o n de f i c iency . Studies on v i t a m i n A and i o d i n e d e f i c i e n c y have been excluded because o f l a c k o f subs tan t ive i n f o r m a t i o n and the na ture o f t h e i r behav iou ra l e f f e c t s . Severe v i t a m i n A de f i c iency r e s u l t s i n b l indness which may prec lude the c h i l d f rom a t tend ing r e g u l a r school ing. I o d i n e d e f i c i e n c y can r e s u l t i n c r e t i n i s m which i s an extreme form o f menta l re ta rda t i on . The concern i n t h i s rev iew i s more w i t h s p e c i f i c and mild-to-moderate e f f e c t s on c o g n i t i v e development t h a t a f f e c t the c h i l d ' s educat iona l process.

Protein-eneruv m a l n u t r i t i o n :

The n u t r i t i o n a l problem w i t h t he h ighes t prevalence i n developing count r ies i s prote in-energy m a l n u t r i t i o n . I n f a n t s and pre-school ch i l d ren , pregnant and l a c t a - t i n g women a re p a r t i c u l a r l y a t r i s k . Protein-energy m a l n u t r i t i o n i s genera l l y caused by a d e f i c i e n t d i e t w i t h i n a severe ly economical ly impoverished environment. Most c h i l d r e n w i t h prote in-energy m a l n u t r i t i o n a re genera l l y b o r n i n t o , and develop in, an unsan i ta ry environment w i t h few e a r l y oppor tun i t i es f o r l e a r n i n g and psychosocia l s t i m u l a t i o n , and a re cons tan t l y exposed t o agents t h a t w i l l l e a d t o i n f e c t i o u s diseases.

The most severe forms o f prote in-energy m a l n u t r i t i o n are: marasmus, kwashiorkor, and marasmus-kwashiorkor. The f i r s t i s t h e r e s u l t o f a d e f i c i e n t d i e t b o t h i n pro- t e i n and energy as w e l l as o f m u l t i p l e o the r depr iva t ions . Severe growth r e t a r d a t i o n i s c h a r a c t e r i s t i c o f t h e marasmic c h i l d . The e t i o l o g y o f kwashiorkor, on the o the r hand, i s b a s i c a l l y due t o a d e f i c i e n t p r o t e i n in take , a l though i t may be p r e c i p i t a t e d by an i n f e c t i o u s episode. Growth r e t a r d a t i o n i s o f t e n par t o f t h e c l i n i c a l p i c t u r e o f t h e kwashiorkor c h i l d . Marasmus-kwashiorkor i s t he most f requent form o f severe m a l n u t r i t i o n seen and combines t h e symptoms o f t h e marasmic and kwashiorkor c h i l d .

Wasting i s another n u t r i t i o n a l term c u r r e n t l y used t o de f i ne severe m a l n u t r i t i o n among i n f a n t s . I t def ines a c h i l d whose body weight i s s i g n i f i c a n t l y behind what i t should be f o r h i s ch rono log ica l age and f o r h i s he igh t . The f o l l o w i n g t a b l e p resents some est imates o f was t ing repo r ted by UNICEF (1984) on 12 t o 23 month-old i n f a n t s i n coun t r i es w i t h d i f f e r e n t i n f a n t m o r t a l i t y ra tes . Among those count r ies w i t h d i f f e r e n t i n f a n t m o r t a l i t y r a t e s o f 100 o r more p e r 1,000 l i v e - b i r t h s the f i g u r e s o f wast ing a r e impress i ve l y high. O u t o f n ine teen coun t r i es i n twelve o f them, 10 p e r cent o r more o f t h e i r 12 t o 23 month-old i n f a n t s a re c l a s s i f i e d as wasted.

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Percentage o f Wasting A g e d 12-23 M o n t h s , 1975 - 1979

GROUP OF COUNTRIES % OF AGE-GROUP GROUP OF COUNTRIES % OF AGE-GROUP

A. VERY H I G H INFANT MORTALITY COUNTRIES ( IMR OVER 100)

B. H I G H INFANT MORTALITY COUNTRIES ( I M R 60 -100)

U p p e r V o l t a

S i e r r a Leone

Yemen A r a b Republic

M a l a w i

Ben in

Lib e r i a

Nepal

Rwanda

S e n e g a l

Yemen, PDR

Bangladesh

Burundi

Egypt

Pakistan

C a m e r o o n

H a i t i

Lesotho

Togo

Z a i r e

17 B u r m a

26 Ghana

17 Indonesia

3 6 l

17

8

27

26

22

36

53

3g2

3

23

5

18

11

9

10

443

39

26

Papua New G u i n e a 52

Tun i s i a 32

Honduras 1 o4 Nicaragua 24

B o t s w a n a

B r a z i l

13

62

E l S a l v a d o r 6 4

G u a t ame l a 74

C o l o m b i a 25

Kenya 8

D o m i n i can R e p u b 1 i C 7

Jordan 9

A v e r a g e 15.6 R a n g e 50.0

C. MIDDLE INFANT MORTALITY COUNTRIES ( I M R 2 6- 5 O

A v e r a g e 21.2 P h i l i pp ines R a n g e 50.0

Thai land

16

18

S r i Lanka 22

Y u g o s l a v i a

Panama

l1

g4

C o s t a R ica 34

1 x A u s t r i a

A v e r a g e 10.0 Range 21 .o

1. 1969 2. 1974 3. 1970 4. 1967 5. 1980 x L o w Infant M o r t a l i t y C o u n t r y ( I M R 25 and less)

S o u r c e : U n i c e f 1984

M e a n ( T o t a l C o u n t r i e s ) = 17.2 Range ( T o t a l C o u n t r i e s ) = 53 - 1 = 52.

- 12 -

Based on what i s known on the socio-economic contex t o f m a l n u t r i t i o n , i t i s t o be expected t h a t t h e m a j o r i t y o f these c h i l d r e n l a b e l l e d as wasted a re l i v i ng under cond i t i ons o f extreme s o c i a l and economic depr iva t ions . Thus as proposed i n t h i s monograph, i t i s t o be expected that a l a r g e p r o p o r t i o n o f these c h i l d r e n i n these coun t r i es w i l l have ser ious d i f f i c u l t y i n a d j u s t i n g t o fo rma l educat iona l demands.

I r o n d e f i c i e n c y anemia:

Th is i s p robab ly the m i c r o n u t r i e n t d e f i c i e n c y w i t h t he h i g h e s t prevalence i n b o t h developed and developing count r ies . Moreover, i n many p a r t s o f t h e wor ld i t genera l l y coex i s t s w i t h prote in-energy m a l n u t r i t i o n o r w i t h o the r m i c r o n u t r i e n t ( v i t a m i n and minera ls ) d e f i c i t s . I t i s now est imated t h a t t he re a r e about 1.3 b i l l i o n people w i t h i r o n d e f i c i e n c y anemia around the wor ld. The f u n c t i o n a l conse- quences o f i r o n d e f i c i e n c y anemia have n o t y e t been f u l l y establ ished. However, t he re i s conc lus ive evidence t h a t i t has a d e b i l i t a t i n g e f f e c t on worker 's produc- t i v i t y , and, as evidenced i n t h i s monograph, on t h e a t t e n t i o n and l e a r n i n g o f ch i l d ren .

I r o n d e f i c i e n c y a n e m i a i s an extreme form o f t h i s m i c r o n u t r i e n t de f ic iency ; how- ever, there may be d e p l e t i o n i n t h e stoxage o r i n t h e t r a n s p o r t o f i r o n be fore the oxygen c a r r y i n g capac i ty o f b lood i s a f fec ted . I r o n d e f i c i e n c y i s genera l l y caused by a d e f i c i e n t i n t a k e o r absorp t ion o f i r o n . Anemia may a l s o be caused by f o l a t e de f i c iency , p a r t i c u l a r l y among pregnant women and ch i ld ren .

V i tamin A .de f i c iency and xerophthalmia:

V i tamin A d e f i c i e n c y i s p r e v a l e n t among popu la t ions where c h i l d r e n a re weaned t o a d i e t t h a t i nc ludes sma l l amounts o f an imal foods, green l e a f y vegetables and f r u i t s . I t causes s i g n i f i c a n t r e d u c t i o n i n the capac i ty o f t h e organism t o r e s i s t i n f e c t i o n , d i so rde rs i n metabolism, and eye les ions i n t h e cornea t h a t p rog ress i ve l y worsen un t i l b l indness occurs. V i tamin A de f i c iency genera l l y e x i s t s i n con junc t ion w i t h p r o t e i n and energy de f ic iency , which i n turn accentuates t h e e f f e c t s o f t h e vitamin de f i c iency .

Xerophthalmia - a l s o c a l l e d 'd isease o f darkness' - i s f r e q u e n t l y found i n c h i l d r e n younger than f i v e years o ld , and r e s u l t s f rom l e s i o n s t o the cornea. As t h e c o n d i t i o n becomes worse t h e c h i l d becomes bl ind and the l e s i o n i s i r r e v e r s i b l e . O f t h e s u r v i v o r s o f severe xerophthalmia i t i s est imated t h a t 25 p e r cent a re t o t a l l y blind, and 15 t o 25 pe r cent have unimpaired s i g h t . The World Hea l th Organizat ion has est imated tha t t h e r e are about one m i l l i o n c h i l d r e n i n t h e w o r l d who have s u f f e r e d f rom some degree o f v i s u a l impaimnent due t o v i t a m i n A de f ic iency . It i s n o t known, however, how many c h i l d r e n a r e n o t ab le t o go t o school, o r do n o t f u n c t i o n w e l l i n school because o f v i s u a l d isorders secondary t o vitamin def ic iency .

I o d i n e d e f i c i e n c y and g o i t r e :

Severe i o d i n e d e f i c i e n c y r e s u l t s i n hypothyr iodism, a p a t h o l o g i c a l s t a t e charac- t e r i z e d by an impajxment i n syn thes iz ing t h y r o i d hormone. Unless the t h y r o i d gland i s non- func t iona l o r absent, t he impairment i s accompanied by g o i t r e , o r t h y r o i d gland enlargement, which r e s u l t s from hypers t imu la t i on o f t h e t h y r o i ä gland. Severe endemic g o i t r e - which i s genera l l y t he r e s u l t o f a d i e t d e f i c i e n t i n i o d i n e - has been c l e a r l y assoc iated w i t h endemic c r e t i n i s m i n d i f f e r e n t w o r l d reg ions (Clements, 1976). A c r e t i n i s charac ter ized by severe i n t e l l e c t u a l r e t a r d a t i o n , d y s a r t h r i a and p o s s i b l y deafness. W i t h few, if any exceptions, c r e t i n s a re n o t ab le t o a t tend school because of t h e i r severe i n t e l l e c t u a l l i m i t a t i o n s . They represent the most dramat ic example of t h e way a n u t r i t i o n a l d e f i c i e n c y may s top a c h i l d f rom t a k i n g advantage o f t he fo rma l educat iona l system.

- 13 -

REFERENCES

ASHWORTH, A. I n t e r n a t i o n a l d i f f e r e n c e s i n i n f a n t m o r t a l i t y and t h e impact o f mal- n u t r i t i o n : a review. Human N u t r i t i o n : C l i n i c a l N u t r i t i o n . Westport, Conn., 3 6 ~ , 1982, 7-23.

BEIRN, R., KINSEY, D.C., McGINN, N.F., Antecedents and consequences o f e a r l y school learn ing . An a n a l y t i c a l survey o f research a c t i v i t i e s . Occasional papers i n educat ion and development. Cambridge, Massachusetts, Harvard U n i v e r s i t y , 1972, 116 pp.

BIRDSALL, N. A c o s t of s i b l i n g s : c h i l d schoo l i ng i n urban Colombia. Research i n Popu la t i on Economics, Greenwich, Connecticut, 2, 1980, 115-150.

CHEN, L. & SCRIMSHAW, N. Diar rhea and m a l n u t r i t i o n . New York. Plenum Press, 1983, 318 pp.

CLEMENTS, F.W. Endemic g o i t r e . In: N u t r i t i o n i n p r e v e n t i v e medicine, p. 83, BEATON, G. & BENGOA J.M., (eds). Geneva, Switzer land, World Hea l th Organizat ion: 1976.

Consortium f o r l o n g i t u d i n a l s tud ies . As t h e t w i g i s bent.. . L a s t i n g e f f e c t s o f pre-school programmes. New Jersey, Larence Erlbaum Associates, 1983, 494 pp.

I n t e r n a t i o n a l Development Research Centre. Prevent ing schoo l f a i l u r e : t h e r e l a t i o n - s h i p between pre-school and p r imary education. Proceedings o f a workshop on pre-school research h e l d i n Bogota Colombia. 26-29 May, Ottawa, Canada, IDRC P u b l i c a t i o n No. 172 e, 1983, 178 pp.

DEERE, C.D. & de LEAL, M.L., Women i n Andean a g r i c u l t u r e . Switzer land, I n t e r n a t i o n a l Labor Organisat ion, Geneva, Switzer land, 1982, 172 pp.

IRWIN, M., ENGLE, P.M., YARBROUGH, C., KLEAIN, R.E. & TOWNSEND, J. The r e l a t i o n s h i p o f p r io r a b i l i t y and f a m i l y c h a r a c t e r i s t i c s t o schoo l attendance and school achievement i n r u r a l Guatemala. C h i l d Development, Chicago, I l l i n o i s , 49, 1978, 4 15-427.

OKEIJIDI, F.O. CALDWELL, J., CALDWELL, P. & WARE, H. The changing A f r i c a n f a m i l y p r o j e c t : a r e p o r t w i t h s p e c i a l re fe rence t o t h e N i g e r i a n segment. S tud ies on Family Planning, New York, New York, 7, 1976, 126-136.

PELLET, P.L. Changing concepts on w o r l d m a l n u t r i t i o n . Ecology o f Food and N u t r i t i o n . London, England, 13, 1983, 115-125.

RAZIN, A., Economic g r o w t h and education-new evidence. Economic Development and C u l t u r a l Change. Chicago, I l l i n o i s , 25, 1977, 317-324.

SIMMONS, J. & ALEXANDER, L., The determinants o f schoo l achievement i n developing count r ies : a rev iew o f research. Economic Development C u l t u r a l Change. Chicago, I l l i n o i s , 23, 1975, 341-357.

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II. EFFECTS OF MALNUTRITION I N INFANCY AND THE PRE-SCHOOL PERIOD ON SCHOOL ACHIEVEMENT AND INTELLECTUAL FUNCTION

Most s tud ies on t h e e f f e c t s o f p r o t e i n and energy m a l n u t r i t i o n during the i n fancy o r pfe-school p e r i o d on the performance i n i n t e l l i g e n c e t e s t s o r i n school achievement measures i n ch i ldhood and adolescence have been r e s t r i c t e d t o cases w i t h a h i s t o r y o f severe prote in-energy m a l n u t r i t i o n . As a l ready ind ica ted , severe prote in-energy m a l n u t r i t i o n i nc ludes kwashiorkor ( p r o t e i n d e f i c i e n c y ) , marasmus (energy and p r o t e i n d e f i c i e n c y ) , and marasmus-kwashiorkor, which combines s igns and symptoms o f b o t h cond i t ions . Moreover, n o t a l l t h e s tud ies r e p o r t school measures: some a r e r e s t r i c t e d t o i n t e l l i g e n c e o r c o g n i t i v e t e s t scores. The i r i n c l u s i o n i n t h i s rev iew i s based on the assumption that i n t e l l i g e n c e t e s t measures a re rough i n d i c a t o r s o f t h e l e a r n i n g a b i l i t y o f t h e c h i l d . I t i s recognized, however, t h a t IQ o r o the r measures o f c o g n i t i v e f u n c t i o n are n o t p e r f e c t l y c o r r e l a t e d w i t h academic achievement and can o n l y be taken as an i n d i v i d u a l ' s l e a r n i n g p o t e n t i a l .

O u t o f t h e t h i r t e e n s tud ies summarized i n Table 1 o f the Appendix ta rge ted t o measure t h e e f f e c t s o f severe prote in-energy m a l n u t r i t i o n i n in fancy and t h e pre- school p e r i o d on school achievement and i n t e l l e c t u a l func t ion , t e n o f t h e s tud ies r e p o r t t h a t i n comparison t o wel l -nour ished c o n t r o l ch i ld ren , c h i l d r e n w i t h a h i s t o r y o f m a l n u t r i t i o n scored s i g n i f i c a n t l y lower i n i n t e l l i g e n c e t e s t scores and school achievement scores. The magnitude o f the d e f i c i t s however observed i n the malnour ished c h i l d r e n i s n o t un i fo rm across s tud ies. Whi le some r e p o r t severe c o g n i t i v e d e f i c i t s i n t h e undernour ished c h i l d r e n and l a r g e d i f f e r e n c e s i n i n t e l l e c - t u a l f u n c t i o n between these c h i l d r e n and t h e i r con t ro l s , o thers r e p o r t very m i l d e f f e c t s f rom e a r l y undernu t r i t i on . F o r example, on the one hand Stoch and Smythe (1976) i n t h e i r 15 year -o ld fo l low-up o f c h i l d r e n w i t h a h i s t o r y o f severe under- n u t r i t i o n i n i n f a n c y r e p o r t t h a t they had a 25 IQ p o i n t d e f i c i t i n comparison t o t h e i r c o n t r o l group. The mean IQ o f t h e boys w i t h a h i s t o r y o f u n d e r n u t r i t i o n was as low as 55.7. O n t h e ot-her hand, t h e I Q s and school achievement o f c h i l d r e n w i t h a h i s t o r y o f m a l n u t r i t i o n who were p laced f o r adopt ion i n a Korean agency and adopted by f a m i l i e s i n t h e Un i ted States (Winick, e t a l . 1979), were lower than t h a t o f t h e i r con t ro l s . However, t h e i r IQ and school performance were s i m i l a r t o , o r h igher than t h a t o f t h e Un i ted Sta tes standards.

Some impor tan t developmental quest ions i n connect ion w i t h t h e na ture and tude o f t he e f f e c t s o f e a r l y prote in-energy m a l n u t r i t i o n have t o do w i t h t h e o f onset o f t h e m a l n u t r i t i o n , t he type o f m a l n u t r i t i o n and i t s seve r i t y .

Four s tud ies (Hoorweg & S t a n f i e l d , 1979; L ien, e t a l . , 1977; Nwuga, 1977 Richardson, 1980) assessed the r e l a t i o n s h i p between t ime o f h o s p i t a l i z a t i o n adopt ion) and s e v e r i t y o f t h e d e f i c i t i n i n t e l l e c t u a l performance. A reason l o o k i n g a t t h e t ime o f h o s p i t a l i z a t i o n i s because i t i s a crude i n d i c a t o r o f

magni- t ime

o r f o r t h e

onset o f the m a l n u t r i t i o n . Three o f these s tud ies found t h a t age a t h o s p i t a l i z a t i o n was independent o f t h e s e v e r i t y o f t h e d e f i c i t . The f o u r t h s tudy (Lien, e t a l . 1977) assessed the impact o f t ime o f admission t o an adopt ion agency (before and a f t e r 3 years o f age) and t h e performance o f t h e c h i l d r e n a t a l a t e r age on school achieve- ment and i n t e l l e c t u a l func t ion . Th is comparative ana lys i s a l s o y i e l d e d no s t a t i s - t i c a l l y s i g n i f i c a n t e f f e c t s o f age a t admission on school performance o r i n t e l l i g e n c e t e s t i n g . However, an ana lys i s o f t h e r e l a t i o n s h i p between t ime o f adopt ion (before o r a f t e r 4 years o f age) by f a m i l i e s f rom t h e Un i ted States and performance y i e l d s t a t i s t i c a l l y s i g n i f i c a n t e f f e c t s . The mean IQ and school performance o f t h e c h i l d r e n adopted be fo re t h e i r f o u r t h birthday was h igher than t h a t o f those adopted a t an o l d e r age.

The f i n d i n g s f rom t h e f o u r s tud ies reviewed i n connect ion w i t h t he r e l a t i o n s h i p between t ime o f h o s p i t a l i z a t i o n c r enrolment i n adopt ion agency and c o g n i t i v e o r

- 15 -

school achievement d e f i c i t s p rov ide no suppor t f o r t h e hypothes is t h a t t h e t i m i n g o f the m a l n u t r i t i o n may be a c r i t i c a l f a c t o r i n t h e magnitude of t h e d e f i c i t observed a t a l a t e r age. However, t h i s i n t e r p r e t a t i o n must be i n t e r p r e t e d cau t ious l y . There i s no way o f assessing accu ra te l y t h e developmental and n u t r i t i o n a l h i s t o r y o f t h e cases s tud ied because o f t h e r e t r o s p e c t i v e na ture o f t h e s tud ies .

I n con t ras t t o t h e negat ive f i n d i n g s on t h e t i m i n g o f h o s p i t a l i z a t i o n t h e evidence on t h e e f f e c t s o f t h e s e v e r i t y o f u n d e r n u t r i t i o n (measured by t h e degree o f s tun t i ng ) i n d i c a t e t h a t t h i s i s a c r i t i c a l developmental v a r i a b l e . The c h i l d r e n adopted from a Korean agency a f t e r t h e i r th i rd b i r t h d a y , (Lien, e t a l . 19771, were d i v i d e d i n t o th ree groups accord ing t o t h e i r degree o f growth r e t a r d a t i o n a t t h e t ime o f enrolment i n t h e agency. L a t e r i n school t h e r e was a p o s i t i v e a s s o c i a t i o n between school performance and IQ and t h e i r i n i t i a l growth r e t a r d a t i o n . The s tudy o f the c h i l d r e n adopted sometime during t h e i x f i r s t two years o f l i f e had a s i m i l a r f inding (Winick, e t a l . 1979). L ikewise, Hoorweg and co-workers (1979) showed an assoc ia t i on between s e v e r i t y o f u n d e r n u t r i t i o n (as i n d i c a t e d by v a r i e d s igns and symptoms) i n e a r l y l i f e and i n t e l l e c t u a l performance during school age.

A wel l -designed s tudy (Grantham-McGregor, 1982) focus ing on pre-school ch i l d ren , analysed t h e r e l a t i o n s h i p s between t h e degree o f growth r e t a r d a t i o n , and o t h e r chemical s igns associated w i t h severe p r o t e i n d e f i c i e n c y and the s e v e r i t y o f i n t e l l e c t u a l performance among c h i l d r e n r e c e n t l y r e h a b i l i t a t e d from severe m a l n u t r i t i o n . The s t ronges t p r e d i c t o r o f i n t e l l e c t u a l d e f i c i t was the degree o f growth r e t a r d a t i o n .

Conversely, Richardson (1980) f a i l e d t o f ind an assoc ia t i on between t ype and sEver i t y o f m a l n u t r i t i o n and degree o f c o g n i t i v e d e f i c i t i n t h e school age per iod . He igh t and weight measures a t admission t o t h e h o s p i t a l were used t o d e f i n e t h e degree o f undernu t r i t i on . These two measures, and a s o c i a l background measure were then c o r r e l a t e d w i t h l a t e r IQ. A n ana lys i s t o measure t h e e f f e c t o f each v a r i a b l e on t h e outcome v a r i a b l e c o n t r o l l i n g f o r t he e f f e c t s o f t h e others, showed t h a t t h e socio-economic background o f t h e c h i l d r e n was t h e o n l y v a r i a b l e t h a t made a s i g n i - f i c a n t c o n t r i b u t i o n t o IQ.

Although t h e f i n d i n g s f rom t h e s tud ies reviewed above a re n o t fu l l y c o n s i s t e n t w i t h each other , most o f t h e evidence supports t h e hypothes is t h a t t h e s e v e r i t y o f t he n u t r i t i o n a l d e f i c i t i s p o s i t i v e l y assoc iated w i t h t he magnitude o f t h e c o g n i t i v e de f i c iency during school age.

Two s tud ies conducted i n t h e Caribbean assessed t h e school behaviour and per - formance o f c h i l d r e n w i t h a h i s t o r y o f severe m a l n u t r i t i o n . One was c a r r i e d o u t i n the i s l a n d of Barbados (Ga l le r , e t a l . 1983) and t h e o t h e r i n Jamaica (Richardson, 1980). The Barbados s tudy showed t h a t malnour ished c h i l d r e n i n comparison t o c o n t r o l c h i l d r e n (matched by age, sex, and handedness) had more s i g n i f i c a n t problems i n a t l e a s t th ree academic r e l a t e d areas: cogn i t ion , s o c i a l i n t e r a c t i o n , and emot ional s t a b i l i t y ( p a r t i c u l a r l y t he g i r l s ) . The Jamaica s tudy a l s o showed that i n comparison t o c o n t r o l c h i l d r e n the malnour ished c h i l d r e n had lower IQ scores and lower academic achievement.

The remaining two s tud ies (Bar te l , e t a l . 1977; Das & Soysa, 1978) r e p o r t e d no de tec tab le e f f e c t s o f t h e n u t r i t i o n a l h i s t o r y . Both s tud ies found that t h e r e were no d i f f e rences i n IQ o r i n o the r measures o f i n t e l l e c t u a l f u n c t i o n between m a l - nour ished and c o n t r o l ch i l d ren . The f i r s t s tudy compared malnourished, (kwashiorkor o r marasmic-kwashiorkor) b l a c k c h i l d r e n w i t h s i b l i n g s and yardmates c lose i n age who were i n good h e a l t h and t h e second study compared malnour ished c h i l d r e n who had been h o s p i t a l i z e d f o r kwashiorkor and marasmus w i t h wel l -nour ished s i b l i n g s and neighbourhood ch i l d ren . Both s tud ies showed no d i f f e r e n c e s between t h e malnour ished and c o n t r o l c h i l d r e n i n any of t h e i n t e l l i g e n c e t e s t s used that were admin is tered i n ch i ldhood o r e a r l y adolescence.

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E f f e c t s o f f a m i l y environment

Richardson (1980) showed t h a t , as compared t o the f a m i l i e s o f t he c o n t r o l s f t h e f a m i l i e s o f t h e malnour ished c h i l d r e n were more economical ly disadvantaged. Moreover, t h e s o c i a l - f a m i l i a l environment o f t he c h i l d r e n was a b e t t e r p r e d i c t o r o f school achievement than the c h i l d ' s h e i g h t (which i s an i n d i c a t o r o f n u t r i t i o n a l h i s t o r y ) . The b e t t e r t h e f a m i l y s i t u a t i o n , t he h igher the chance o f i n t e l l e c t u a l r e h a b i l i t a t i o n among the malnour ished ch i ld ren . Ana lys is of the i n t e r a c t i o n s between a c h i l d ' s s o c i a l background and c h i l d ' s h e i g h t i n d i c a t e d t h a t those worse o f f were s h o r t and l i v e d among t h e most severe ly depr ived fam i l i es .

The s a l u t a r y e f f e c t s o f a f a m i l y environment on t h e development o f menta l a b i l i t i e s and school competence a re c l e a r l y observed i n t h e two adopt ion s tud ies (Winick e t a l . 1979; L ien , e t a l . 1977). Both i nc luded c h i l d r e n who were severe ly malnour ished i n in fancy , l a t e r housed by an adopt ion agency, and subsequently adopted by f a m i l i e s who met t h e c h i l d r e n ' s p h y s i o l o g i c a l and psychosoc ia l needs. Accordingly, when t h e c h i l d r e n were a t school t he seque la i from t h e i r e a r l y n u t r i t i o n a l trauma was minimal, and they cou ld per fo rm i n the fo rmal educat iona l system up t o the l e v e l o f t h e n a t i o n a l standards.

C r i t i q u e o f t he s tud ies

A c r i t i c a l methodologica l problem shared by a l l t h e s tud ies i nc luded i n t h i s s e c t i o n i s t h e i r use o f a r e t r o s p e c t i v e research design. The i n v e s t i g a t i o n s were conducted once t h e c h i l d r e n were a l ready malnourished, o r f o l l o w i n g n u t r i t i o n r e h a b i l i t a t i o n . Accord ing ly , i t was p r a c t i c a l l y impossib le f o r t he i n v e s t i g a t o r s t o demonstrate accu ra te l y t h a t t h e malnourished and t h e c o n t r o l - c h i l d r e n were developmental ly and s o c i a l l y equ iva len t p r i o r t o t h e onset o f m a l n u t r i t i o n . The malnour ished c h i l d r e n may have been developmental ly handicapped b e f o r e they becane malnourished; thus, t he d i f f e r e n c e s observed between malnour ished and c o n t r o l c h i l d r e n i n t h e i r school performance o r i n measures o f c o g n i t i v e func t ion , may n o t be due t o the d i f f e rences i n t h e i r n u t r i t i o n a l h i s t o r y . by Richardson (1980) the re a re s t rong reasons t o suspect nour ished c h i l d r e n a r e o f t e n more severe ly depr ived than n i t i e s but w i t h w e l l nour ished ch i l d ren .

Moreover, as demonstrated that t h e f a m i l i e s o f mal- those from the same commu-

Conclusions

From a s t r i c t l y s c i e n t i f i c pe rspec t i ve i t must b e concluded tha t , because o f methodologica l l i m i t a t i o n s , t h e da ta f rom the s tud ies reviewed do n o t p rov ide a b a s i s f rom which t o i n f e r t h a t m a l n u t r i t i o n i s a causal r i s k f a c t o r f o r t he c o g n i t i v e development o f ch i l d ren . However, i t must b e recognized t h a t t he re i s an impressive consis tency i n t h e na tu re o f t h e research f ind ings . C lea r l y , t he re i s a t r e n d i n t h e data t h a t suggests t h a t m a l n u t r i t i o n i s a developmental r i s k fac to r , and t h a t i t c o e x i s t s w i t h an a r ray o f o t h e r b i o p h y s i c a l and s o c i a l environmental fac to rs t h a t a r e a l s o hazardous t o t h e psychosoc ia l development o f ch i l d ren . Thus, w h i l e no s tudy stands a lone t o demonstrate t h e l o n g term f u n c t i o n a l consequences o f e a r l y m a l n u t r i t i o n , t he body o f da ta ava i l ab le , p laced i n the contex t o f , o r understanding o f , c h i l d development, de f ines m a l n u t r i t i o n as a r i s k f a c t o r i n t h e fo rmal educa- t i o n a l process.

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REFERENCES

BARTEL, P.R., BURNETT, L.S., GREISEL, R.D., FREIMAN, I., ROSEN, E.U. & GEEFHUSYEN, J. func t i on . Psychologia A f r i cana. Braamfontein, South A f r i c a , 17(2) , 1977,

The e f f e c t s of kwashiorkor on performance on t e s t s o f neuropsychologica l

153- 160.

DAS, J.P. & SOYSA, P. La te e f f e c t s o f m a l n u t r i t i o n on c o g n i t i v e competence. I n t e r - n a t i o n a l Jou rna l o f Psychology, Amsterdam, Nether lands, 13(4) , 1978, 296-302.

GALLER, JR., RAMSEY, F., SOLIMANO, G. & LOWELL, WE. The i n f l u e n c e o f e a r l y malnu- t r i t i o n on subsequent behav iou ra l development. II. Classroom behaviour. j o u r n a l o f t he American Academy o f C h i l d Psychiat ry , New Haven, Connect icut , 22 (1) , 1983, 8-15.

GRAHAM G.G. & ADRIANZEN, B.T. S ta tus i n school o f Peruv ian c h i l d r e n severe ly mal- nour ished i n in fancy . In: Behav ioura l e f f e c t s o f energy and p r o t e i n d e f i c i t s , p. 185, Brozek, J. (ed). Bethesda, Maryland, NIH P u b l i c a t i o n No. 79-1906, 1976.

GRANTHAM-McGREGOR, S. The r e l a t i o n s h i p between developmental l e v e l and d i f f e r e n t types o f m a l n u t r i t i o n i n ch i l d ren . Human N u t r i t i o n : C l i n i c a l N u t r i t i o n , 1982, 36C, 319-320.

HOORWEG, J. & STANFIELD, J.P. I n t e l l e c t u a l a b i l i t i e s and prote in-energy ma ìnu t r i - t i o n : acute m a l n u t r i t i o n versus chron ic u n d e r n u t r i t i o n . Behavioura l E f f e c t s o f energy and p r o t e i n d e f i c i t s . , p. 148, BROZEK, J. (ed.) Bethesda, Maryland, NIH P u b l i c a t i o n No. 79-1906, 1979.

LIEN, N.M., MEYER, K.K. & WINICK, M. E a r l y m a l n u t r i t i o n and ' l a t e ' adoption: a study o f t h e i r e f f e c t s on t h e development o f Korean orphans adopted i n t o American Fami l ies . American Jou rna l o f C l i n i c a l N u t r i t i o n , Bethesda, Maryland, 30, 1977, 1734-1739.

NWUGU, r.c.b., E f f e c t o f severe kwashiorkor on i n t e l l e c t u a l development among N ige r ian ch i ld ren . American Jou rna l o f C l i n i c a l N u t r i t i o n , Bethesda, Maryland, 3 0 , 1977, 1423-1430.

RICHARDSON, S.A. The l o n q range consequences o f m a l n u t r i t i o n i n in fancy : A s tudy o f c h i l d r e n i n Jamaica, -West- I nd ies . - Topics i n Paed ia t r i cs , Kent England, 2 , 1980 , 164-176.

STOCH, M.B. & SMYTHE, P.M., 15 year developmental s tudy on e f f e c t s o f severe under- nu t r i t ion during in fancy on subsequent p h y s i c a l growth and i n t e l l e c t u a l func- t i o n i n g . Arch ives of Disease i n Childhood, London, England, 51, 1976, 327- 331.

WINICK, M., MEYER K.K., HARRIS, R.C., M a i n u t r t t i o n and environmental enrichment by e a r l y adopt ion. Science, Washington, D.C., 190, 1979, 1173-1175.

- 18 - III. NUTRITIONAL STATUS, SCHOOL ACHIEVEMENT AND INTELLECTUAL FUNCTION

Are t h e c o g n i t i v e o r l e a r n i n g a b i l i t i e s o f t he undernour ished o r i r o n d e f i c i e n t anemic c h i l d i n jeopardy? Does i r o n d e f i c i e n c y anemia, o r hunger, a f f e c t a t t e n t i o n , concent ra t ion o r memory i n t h e classroom s e t t i n g ? Th is s e c t i o n focuses on these quest ions r e l e v a n t t o m i l l i o n s o f c h i l d r e n i n the developing world, and o f c r i t i c a l importance f o r educat iona l p o l i c i e s .

Four o f t h e s tud ies reviewed r e l a t e n u t r i t i o n a l s ta tus measures such as growth r e t a r d a t i o n o r i r o n d e f i c i e n c y w i t h school performance and behaviour. A f i f t h study i nc luded i n t h e rev iew focuses on t h e assoc ia t i on between t a k i n g o r n o t t a k i n g break fas t , and problem-solv ing a t lunch t ime.

Growth r e t a r d a t i o n

A s tudy conducted i n Singapore (Chun, 1971) assessed the r e l a t i o n s h i p between t h e physique o f s tudents and success i n pass ing t h e Pr imary V I examination. 12 year o l d c h i l d r e n were c l a s s i f i e d accord ing t o body s i z e i n t o th ree groups: t a l l (90 p e r cent p e r c e n t i l e Hong Kong growth s tandard) , average (10 p e r cent and 90 p e r cent p e r c e n t i l e growth standard) and sma l l (below 10 pe r cent p e r c e n t i l e ) . F ind ings showed a s t a t i s t i c a l l y s i g n i f i c a n t assoc ia t i on between t h e number o f f a i l u r e s in . t he examinat ion and t h e body s i z e group c l a s s i f i c a t i o n . Ch i l d ren i n the t a l l group had a 78 p e r cent chance o f pass ing the examination; those i n the average group a 50 pe r cent chance and those i n t h e sma l l group had o n l y a 25 p e r cent chance o f pass ing the examination.

Some methodologica l problems i n t h i s study must be taken i n t o account be fore drawing conclusions.

The s tudy prov ides no i n f o r m a t i o n on t h e socio-economic s ta tus o f t he ch i l d ren . Th is omission i s un fo r tuna te because i t i s w e l l known t h a t r a t e o f p h y s i c a l growth i s assoc iated w i t h socio-economic s t a t u s which a l s o a f f e c t s t h e development o f l e a r n i n g ap t i t udes and a t t i t u d e s . Thus, i t i s impossiBle t o d i s c r i m i n a t e between those e f f e c t s from n u t r i t i o n a l s t a t u s and those from socio-economic background.

The da ta f rom t h i s s tudy does n o t s u f f i c e t o determine whether the educat ional e f f e c t s a t t r i b u t e d t o n u t r i t i o n a r e r e l a t e d t o p a s t n u t r i t i o n a l h i s t o r y o r t o p resent n u t r i t i o n a l s ta tus . The poor school performance o f t he sma l l group c h i l d r e n cou ld be r e l a t e d t o an i n t e l l e c t u a l d e f i c i t assoc iated w i t h an e a r l y h i s t o r y o f under- n u t r i t i o n . A l t e r n a t i v e l y they cou ld a l s o r e s u l t f rom d e f i c i t s i n a t t e n t i o n and concent ra t ion r e l a t e d t o cu r ren t n u t r i t i o n a l de f i c ienc ies . The l i m i t e d in fo rmat ion repo r ted i n t h e paper prec ludes a conc lus ive in ference.

Another s tudy (Popkin 8, Lin-Ybanez, 1982) on genera l n u t r i t i o n a l s ta tus and school achievement among 12 - 14 year o l d c h i l d r e n conducted i n the P h i l i p p i n e s addressed two quest ions. One d e a l t w i t h t h e r e l a t i o n s h i p between (a) body s i z e (weight /he ight ) and (b) hemoglobin measures t o d e t e c t anemia and performance i n an educat iona l achievement measure.

Low hemoglobin va lues - which i s an i n d i c a t i o n o f anemia - was associated w i t h l o w scores i n a language lean ing t e s t and i n a composite t e s t score. Low hemoglobin va lues were a l s o r e l a t e d t o high absenteeism. L ikewise a smal l body s i z e (weight- f o r -he igh t measure) - which i s i n t e r p r e t e d as an i n d i c a t i o n o f prote in-energy under- n u t r i t i o n - was r e l a t e d t o poor scores i n t e s t s o f mathematics and poor concentka- t i o n . These assoc ia t ions between n u t r i t i o n a l s ta tus measures and school performance remained a f t e r t h e e f f e c t s o f t h e socio-economic s ta tus o f t he c h i l d r e n were con t ro l l ed .

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A l i m i t a t i o n o f t h i s s tudy i s t h a t i t does n o t p rov ide s u f f i c i e n t d e t a i l e d i n f o r m a t i o n on t h e body measures c h a r a c t e r i s t i c s o f t h e students. O n t h e o the r hand the c o r r e l a t i o n repo r ted between hemoglobin and school performance i s most r e v e a l i n g i n t h e l i g h t o f t h e da ta now a v a i l a b l e on i r o n d e f i c i e n c y and cogn i t ion .

I r o n def i c iencv anemia

Two s tud ies i n t h e Un i ted States o f America have assessed t h e r e l a t i o n o f i r o n def ic iencyanemia andschoolperformance (Webb &Osk i , 1973; 1974). Bothwere conducted among12- 14yearo ldp redomina te l yb lack s tudents a t tend ingasecondary school i n an economical ly depr ived urban area. The anemic s tudents had hemoglobin which ranged from 10.1 t o 11.4 grams ( g m / d l ) w h i l e t h a t o f t he c o n t r o l s ranged from 14.0 t o 14.9 grams ( g m / d l ) . The outcome measures used were a composite score o f t h e Iowa Tests o f Basic S k i l l s , Leve ls A-F/Form 3, and a behav iou ra l adjustment sca le which i nc luded i tems on aspects o f p e r s o n a l i t y disturbances, inadequacy-immaturity, and conduct problems.

The composite score i n t h e Iowa Tes t o f t h e anemic s tudents was s i g n i f i c a n t l y lower than t h a t o f t he c o n t r o l students. Moreover, t he lowest l e v e l o f performance was observed among t h e o l d e r anemic ch i l d ren . The adjustment r a t i n g s f a i l e d t o y i e l d any s t a t i s t i c a l l y s i g n i f i c a n t f i n d i n g s . The o n l y finding which suggested a between-group behav ioura l d i f f e r e n c e was the r a t i n g r e l a t e d t o conduct problems. Anemic s tudents tended t o have more severe conduct d is turbances than non-anemic students, regard less o f age.

A c r i t i c a l ques t ion i n these two s tud ies on predominant ly b l a c k adolescents i s whether o r n o t these s tudents were indeed anemic. B lack popu la t ions genera l l y have hemoglobin l e v e l s which a re lower (about0.5 t o 1.0 grams (gm/dl) than t h a t o f Caucasians. Among wel l -nour ished popu la t i ons t h i s d i f f e r e n c e i s n o t r e l a t e d t o d i f f e rences i n t h e i n t a k e o r absorp t ion o f i r o n , but i s l i k e l y t o be r e l a t e d t o genet ic d i f f e rences . Thus, a t i ssue here i s how many o f t h e c h i l d r e n i n t h e two s tud ies were genuine cases o f anemia. Socio-economic d i f f e r e n c e s between groups cou ld w e l l account f o r t h e d i f f e r e n c e s i n achievement measures repor ted.

A w e l l - c o n t r o l l e d exper imenta l s tudy on the r e l a t i o n s h i p between i r o n d e f i c i e n c y anemia and school performance was conducted i n Semarang, Indonesia (Sumantr i &

P o l l i t t , 1984). T h i s s tudy i nc luded 9 t o 12 year o l d c h i l d r e n from th ree r u r a l schools. P r i o r t o the f i r s t behav iou ra l evaluat ion, c h i l d r e n were t r e a t e d f o r p a r a s i t e s t o ensure e f f e c t i v e abso rp t i on o f i r o n supplements. The c h i l d r e n were c l a s s i f i e d as e i t h e r i r o n d e f i c i e n t anemic o r non-anemic and then t e s t e d w i t h an IQ t e s t (Raven Progress ive Ma t r i ces ) , a concent ra t ion task, and an achievement t e s t which i nc luded f o u r sub jec t areas: b i o l o g y , language, a r i t h m e t i c , and s o c i a l s tud ies . The i r o n d e f i c i e n t anemic c h i l d r e n and non-anemic c o n t r o l c h i l d r e n were then randomly assigned t o e i t h e r an i r o n t rea tment group ( r e c e i v i n g i r o n supplements) o r a placebo t reatment group (no i r o n supplements). Three months a f t e r t reatment , t he c h i l d r e n took f o r a second t ime t h e achievement school measures and t h e concent ra t ion task. The i r o n body i n d i c a t o r s (hemoglobin and t r a n s f e r r i n s a t u r a t i o n ) o f t he i r o n d e f i c i e n t c h i l d r e n who had been t r e a t e d w i t h i r o n had s i g n i f i c a n t l y changed, and were a t t he same l e v e l as t h a t o f t he non-anemic c o n t r o l ch i l d ren . I n the f i r s t eva lua t ion , t h e i r o n d e f i c i e n t anemic c h i l d r e n scored s i g n i f i c a n t l y beh ind t h e c o n t r o l c h i l d r e n i n the concent ra t ion task and i n t h e school achievement measure. Fo l l ow ing the i r o n t reatment i n t e r v e n t i o n the re was a s t a t i s t i c a l l y s i g n i f i c a n t improvement i n the school t e s t performance o f t h e i r o n d e f i c i e n t anemic c h i l d r e n r e c e i v i n g i r o n supple- ments. Conversely, t h e mean scores i n a l l t e s t s o f t he o the r t h r e e groups were n o t s i g n i f i c a n t l y d i f f e r e n t between t h e f i r s t and second evaluat ions. Th is s tudy p rov ides some o f t h e most c l e a r exper imenta l evidence c u r r e n t l y a v a i l a b l e o f t he s a l u t a r y e f f e c t s o f i r o n t rea tment on l e a r n i n g cif school-age c h i l d r e n who a r e i r o n d e f i c i e n t .

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One i ssue n o t addressed i n t h i s Indonesian s tudy i s t he ques t ion o f which s p e c i f i c c o g n i t i v e processes, a f f e c t e d by i r o n def ic iency, i n t e r f e r e w i t h learn ing . A t ten t i on , maintenance, s e l e c t i v e a t t e n t i o n , concentrat ion, pe rcep tua l o rgan iza t ion , shor t - term memory, o r conceptual learn ing , a re some o f t he c o g n i t i v e processes t h a t a re l i k e l y t o be a f fec ted , but conc lus ive evidence i n t h i s regard i s n o t y e t ava i l ab le .

Hunger

A r e c e n t l y pub l i shed paper ( P o l l i t t , e t a l . 1983) focused on shor t - term f a s t i n g and i t s e f f e c t s on problem-solv ing among 9 t o 11 year o l d wel l -nour ished middle-class ch i l d ren . The paper i nc ludes t h e r e s u l t s o f two exper imenta l s tud ies that used the s i m i l a r research p r o t o c o l and obta ined s i m i l a r f i nd ings . The c h i l d r e n were brought i n t o a c l i n i c a l research cen t re i n t h e l a t e af ternoon. A complete medica l examina- t i o n was g i ven and t h e c h i l d r e n were f e d d inner . They spent t h e night a t t he centre: i n t h e morning they were e i t h e r f e d b r e a k f a s t o r had t o f a s t up t o noon-time when they a te lunch . problem-solv ing ab i l i t y , i n c i d e n t a l l e a r n i n g and short- term memory. A week l a t e r t h e c h i l d r e n re tu rned t o the cen t re and fo l l owed the same research p ro toco l ; however, a t t h i s second admission the b r e a k f a s t t reatment was reversed. Those c h i l d r e n t h a t a t e b reak fas t i n t h e f i r s t sess ion f a s t e d i n t h e second session, and v i c e versa.

A tnoon,be fore a b a t t e r y o f t e s t s was g i ven t o measure cogni t ivetempo,

I n comparison t o t h e f a s t i n g s t a t e the c h i l d r e n i n the b reak fas t c o n d i t i o n made l e s s e r r a r s i n t h e problem-solv ing s i t u a t i o n . Moreover, t h e c h i l d r e n i n the f a s t i n g s t a t e p a i d more a t t e n t i o n t o t h e s t i m u l i t h a t were i r r e l e v a n t t o the task a t hand; t h a t i s , under t h i s c o n d i t i o n t h e c h i l d r e n were more l i k e l y t o use i n e f f e c t i v e c o g n i t i v e s t r a t e g i e s i n problem-solv ing.

Conversely, an exper imenta l s tudy (D ick ie & Bender, 1982) conducted i n the Un i ted Kingdom, f a i l e d t o show any e f f e c t s o f o m i t t i n g b reak fas t on d i f f e r e n t cogni- t i v e measures. I n a board ing school s tudents were randomly assigned t o two groups and were t e s t e d i n t h e f i r s t week on t h r e e consecut ive days a f t e r t h e i r normal b reak fas t r o u t i n e . The n e x t week s tudents were again t e s t e d on t h r e e consecut ive mornings but the exper imenta l group omi t ted b reak fas t w h i l e the c o n t r o l group a t e b r e a k f a s t as usual . Cogn i t i ve performance was assessed by two shor t - term memory tes ts , a memory search t e s t , a se r ies o f numer ica l a d d i t i o n s and an a t t e n t i o n demand t e s t . The s tudy showed no d i f f e rences i n performance between groups t h a t cou ld be a t t r i - bu ted t o t h e omiss ion o f consumption o f b reak fas t .

C r i t i q u e o f t h e s tud ies

The research s tud ies reviewed i n t h i s sec t i on are n o t f r e e o f methodologica l problems. As i n d i c a t e d before, t h e s tudy i n Singapore (Chun 1971) p rov ides i n s u f - f i c i e n t i n f o r m a t i o n t o d i s c r i m i n a t e c l e a r l y whether the p a s t n u t r i t i o n a l h i s t o r y o f t h e s tudents o r t h e i r c u r r e n t n u t r i t i o n a l s ta tus adverse ly a f f e c t s t h e i r school performance. A s i m i l a r problem e x i s t s i n the s tudy i n the P h i l i p p i n e s (Popkin & L i m - Ybanez, 1982). Both s tud ies a l s o f a i l t o p rov ide s u f f i c i e n t i n f o r m a t i o n on the

socio-economic background o f the sub jec ts . There i s evidence o f a p o s i t i v e r e l a - t i o n s h i p between socio-economic s t a t u s and school achievement even among c h i l d r e n r a i s e d i n r u r a l popu la t ions where m a l n u t r i t i o n i s endemic. Moreover, w i t h i n these popu la t ions t h e r e i s a l s o a r e l a t i o n s h i p between pre-school measures o f i n t e l l e c t u a l competence and subsequent school achievement and enrolment (Irwin, e t a l . 1978).

The two s tud ies (Webb & Oski, 1973; 1974) on i r o n d e f i c i e n c y anemia a l s o face t h e problems o f d iagnos t i c s e n s i t i v i t y and l a c k o f i n fo rma t ion on t h e socio-economic background o f t h e students. A s a l ready noted, some, i f n o t most, o f the c h i l d r e n i nc luded i n these s tud ies were probab ly n o t i r o n d e f i c i e n t anemic as they were l abe l l ed . most economical ly depr ived students w i t h i n t he classroom, and t h e i r poor scho las t i c

It i s p o s s i b l e t h a t t h e s tudents who were c l a s s i f i e d as anemic were the

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performance was due t o t h e i r s o c i a l s t a t u s and n o t t o t h e i r i r o n s ta tus . F i n a l l y , t h e study on hunger ( P o l l i t t , e t a l . 1983) was conducted i n an exper imenta l s i t u a t i o n which i s subs tan t i ve l y d i f f e r e n t f rom t h e con tex t o f a classroom; thus, the ecolo- g i c a l v a l i d i t y o f t h i s s tudy i s quest ionable. The c o g n i t i v e problems i d e n t i f i e d among the c h i l d r e n i n t h e no-breakfast s i t u a t i o n may n o t man i fes t themselves i n t h e school. The s tudent may l e a r n how t o compensate e f f e c t i v e l y i n t h e classroom f o r such c o g n i t i v e l i m i t a t i o n r e l a t e d t o the f a c t t h a t he has n o t eaten f o r t o o many hours.

Conclusion

As i n d i c a t e d above, t h e s tud ies reviewed are n o t f r e e o f methodologica l shor t - comings. They a l l have a c e r t a i n degree o f unce r ta in t y ; there fore , f r o m each one o f them i t i s l e g i t i m a t e o n l y t o draw t e n t a t i v e in ferences, r a t h e r than conc lus ive statements. These u n c e r t a i n t i e s , however, f u l f i l l an impor tan t s c i e n t i f i c f u n c t i o n by r a i s i n g c r i t i c a l quest ions about b a s i c i ssues o f human development.

A t t h e same t ime i t must be recognized that most s tud ies reviewed concur i n suggest ing t h a t t h e n u t r i t i o n a l s t a t u s o f t h e s tudent i s a v a r i a b l e tha t determines i n p a r t educat ional performance. The undernour ished c h i l d , t he anemic c h i l d , o r t he c h i l d who goes t o school w i t h o u t e a t i n g a f t e r an ove rn igh t f a s t , does n o t m a i n t a i n a classroom behaviour conducive t o op t ima l l ea rn ing . T h i s i n fe rence, drawn f rom a number o f s tud ies, c a r r i e s an enormous we igh t when i t i s recognized t h a t t h e nutri- t i o n a l s ta tus o f m i l l i o n s o f s tudents around the wor ld i s f a r f rom s a t i s f a c t o r y .

A c r i t i c a l i ssue faced by pol icy-makers concerned w i t h educat ion i s t h e d i s - t i n c t i o n t h a t needs t o be d r a w n between r i s k assessment and r i s k management. O n t h e one hand, the s c i e n t i s t s have had ser ious l i m i t a t i o n s i n assessing p r e c i s e l y t h e l e v e l o f r i s k associated w i t h m a l n u t r i t i o n . Th i s i s n o t due t o s c i e n t i f i c n e g l i - gence, but t o the complex i ty o f measuring, i n t h e human context , t h e e f f e c t s o f a p a r t i c u l a r v a r i a b l e i n a complex e c o l o g i c a l s e t t i n g . I n the o the r hand, t h i s does n o t negate t h a t t h e a v a i l a b l e da ta a l ready c a l l s for t h e management o f t he r i s k associated w i t h m a l n u t r i t i o n . Al though we may n o t be ab le t o e s t a b l i s h exac t d i f f e r - ences, i t i s a l ready known t h a t t h e wel l -nour ished c h i l d i s more competent i n t h e classroom than t h e undernour ished c h i l d - and t h a t t h i s d i f f e r e n c e i s cumulat ive, o r tends t o increase w i t h t ime.

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REFERENCES

CHUN, F.Y., N u t r i t i o n and educat ion - a study. The Journa l o f t he Singapore P e d i a t r i c Society, Singapore, 13(2) , 1971, 91-96.

DICKIE, N. and BENDER A., Break fas t and Performance on Schoolch i ldren. B r i t i s h Jou rna l o f N u t r i t i o n No. 48: 483 - 487, 1982.

IRWIN, M. ENGLE, P.M., YARBROUGH, C . , KLEIN, R.E. & TOWNSEND, J. The r e l a t i o n s h i p of p r i o r ab i l i t y and f a m i l y c h a r a c t e r i s t i c s t o school attendance and school achievement i n r u r a l Guatemala. C h i l d Development, 1978, 49, 415-427.

POLLITT, E., LEWIS, N.L., GARZA, C. & SHULMAN, R.J., F a s t i n g and c o g n i t i v e func t i on . Jou rna l of P s y c h i a t r i c Research, Elmsford, New York 17(2) , 1983. 169-174.

POPKIN, B. & Lim-Ybanez, M., N u t r i t i o n and school achievement. S o c i a l Science and Medicine, Exeter, Devon, England, 16, 1982, 53-61.

SUMATRI, A. and POLLITT, E., I r o n d e f i c i e n c y and school achievement among Indonesia schoolch i ldren, paper presented a t t h e I n t e r n a t i o n a l N u t r i t i o n a l Anemia Consu l ta t i ve Group, 1984 meet ing B a l i , Indonesia.

WEBB, TE. & OSKI, FA. I r o n d e f i c i e n c y anemia and s c h o l a s t i c achievement i n young adolescents. Jou rna l of P e d i a t r i c s , S t . Louis, Missour i , 82(5), 1973, 827- 830.

WEBB, TE. & OSKI, FA. Behavioura l s ta tus o f young adolescents w i t h i r o n d e f i c i e n c y anemia. Jou rna l o f Spec ia l Education, New York, New York, 8 (2 ) , 1974, 153-157.

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I V . NUTRITION INTERmNTION, SCHOOL ACHIEVEMENT AND INTELLECTUAL FUNCTION

Th is s e c t i o n focuses on t h e e f f e c t s o f n u t r i t i o n a l l y supplementing t h e d i e t o f t h e c h i l d i n e a r l y l i f e and d u r i n g t h e school age per iod , on the c h i l d ' s achieve- ment and performance i n school. I n t h e prev ious s e c t i o n i t was es tab l i shed t h a t n u t r i t i o n a l d e f i c i e n c i e s ( i .e . i r o n d e f i c i e n c y anemia) represent educat iona l r i s k f a c t o r s , and p lace i n jeopardy t h e progress o f c h i l d r e n i n school. Accord ing ly , i t i s reasonable t o assume t h a t t a rge ted n u t r i t i o n i n t e r v e n t i o n s w i l l have p r e v e n t i v e o r therapeut ic e f f e c t s .

Programatic ac t i ons on n u t r i t i o n supplementation t a r g e t e d t o n u t r i t i o n a l l y a t - r i s k people, however, must take i n t o account t h a t these, l i k e any o the r s o c i a l i n t e r v e n t i o n , do n o t operate i n a vacuum. Target s e t t i n g and programme implementat ion does n o t necessa r i l y mean t h a t t h e t a r g e t s o f t h e programme w i l l be reached and t h e goals w i l l be f u l f i l l e d . General ly, t he re a re a number o f confounding fac to rs , i n and ou ts ide t h e programme, t h a t c o n d i t i o n i t s e f fec t i veness and the degree t o which t h e goals of t h e i n t e r v e n t i o n are met. For example, school feed ing programmes a re expected t o r a i s e t h e t o t a l food i n t a k e o f t h e c h i l d supplementing t h e c h i l d ' s household d i e t . However, t h e family may take t h e c h i l d ' s school i n t a k e as savings, and decrease p r o p o r t i o n a t e l y t h e c h i l d ' s food i n t a k e a t home. Thus, a f t e r t h e implementation of t h e school feed ing programme t h e c h i l d ' s t o t a l food i n t a k e w i l l be on l y s l i g h t l y h igher , o r perhaps t h e same, as the c h i l d ' s u s u a l i n t a k e be fo re t h e programme.

E a r l v suwwlementation

I n t h e m i d - s i x t i e s a t l e a s t f i v e ambi t ions l o n g i t u d i n a l exper imenta l s tud ies were s e t up i n d i f f e r e n t p a r t s o f t h e wor ld (Colombia, Guatamala, Mexico, Taiwan, Un i ted States) t o assess whether n u t r i t i o n supplementation t o n u t r i t i o n a l l y a t - r i s k urban and r u r a l popu la t ions had an e f f e c t on t h e c o g n i t i v e development o f i n f a n t s and ch i l d ren . The t a r g e t samples were pregnant and l a c t a t i n g women, and t h e i r o f f s p r i n g . These s tud ies assumed t h e f o l l o w i n g : a) t h a t a n e t inc rease i n t h e d i e t a r y i n t a k e o f pregnant women has a s a l u t a r y e f f e c t on t h e i n t r a u t e r i n e env i ron- ment , p revents f o e t a l m a l n u t r i t i o n , and i s conducive t o t h e normal growth of t h e c e n t r a l nervous system i n t h e o f f s p r i n g ; b) supplementation during l a c t a t i o n increased t h e volume o f maternal m i l k and/or improved i t s b iochemica l p r o f i l e f o s t e r i n g t h e growth and development o f t h e i n f a n t ; c) t h a t d i r e c t supplementation t o t h e i n f a n t and young c h i l d prevented m a l n u t r i t i o n and i t s adverse e f f e c t s on t h e b r a i n , acce le ra ted p h y s i c a l growth, and improved res i s tance t o i n f e c t i o n .

Many o f t h e assumptions from most o f these s tud ies on n u t r i t i o n supplementation have n o t been f u l f i l l e d (Joos & P o l l i t t , 1984). There i s l i t t l e evidence t h a t t h e d i e t a r y supplementation had any subs tan t i ve e f f e c t s on t h e c o g n i t i v e development during the pre-school o r school age per iod . For example, one of these f i v e nutr i- t i o n a l supplementation s tud ies (Wilson, 1981) showed t h a t t h i s e a r l y i n t e r v e n t i o n was n o t d i r e c t l y r e l a t e d t o t h e c h i l d r e n ' s school performance. O n t h e o the r hand, t h e t a l l e s t ch i l d ren , o r p robab ly t h e b e t t e r nour ished i n t h e pre-school pe r iod , obta ined t h e h i g h e s t grades l a t e r i n school.

One study conducted i n Mexico (Chavez & Mart inez, 1981) did show, however,. s t r i k i n g developmental b e n e f i t s from a highly ta rge ted n u t r i t i o n i n t e r v e n t i o n i n a r u r a l Mexican popu la t ion . Supplementation o f .20 mothers began i n e a r l y pregnancy and was cont inued w i t h t h e i r o f f s p r i n g un t i l approx imate ly t h e third month a f t e r birth. Another group o f pregnant mothers from t h e same community who did n o t rece ive food supplementation were fo l l owed throughout t h e study. I n the f i r s t year o f school ing t h e supplemented c h i l d r e n scored s i g n i f i c a n t l y h ighe r than t h e un- supplemented ones i n a l l t h e achievement t e s t s t h e y took. Among t h e l a t t e r group

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about 35 p e r cen t o f t h e c h i l d r e n f a i l e d on t h e end-of-course exams, w h i l e none o f t h e supplemented c h i l d r e n f a i l e d . There were no between group d i f f e rences i n IQ o r i n t h e a b i l i t y o f t h e c h i l d r e n t o read and w r i t e .

A c r i t i c a l i ssue i n connect ion w i t h t h e e f f e c t s o f t h i s n u t r i t i o n a l i n t e r - v e n t i o n i s whether these e f f e c t s were s t r i c t l y due t o nutrition. There were o the r i n t e r v e n i n g v a r i a b l e s t h a t had the p o t e n t i a l o f hav ing an impact on t h e development o f t h e exper imenta l c h i l d r e n confounding t h e e f f e c t s o f t h e n u t r i t i o n i n te rven t ion . The d e l i v e r y o f t he food supplement i s l i k e l y t o have increased t h e s o c i a l con tac ts and i n t e r a c t i o n s o f t h e r e c i p i e n t s . Moreover, t h e supplemented c h i l d r e n were a few ( n o t more than twenty) ' se lec ted ' c h i l d r e n i n the v i l l a g e who rece ived a p a r t i c u l a r t rea tment n o t a v a i l a b l e t o everyone. The p o t e n t i a l e f f e c t s o f t h i s s o c i a l aura cannot be dismissed.

Independent ly f rom t h e na ture o f t h e i n t e r v e n t i o n , t h e s tudy i n Mexico does show conc lus i ve l y t h e developmental importance o f e a r l y experiences. I t d e p i c t s a c l e a r p i c t u r e o f t h e p l a s t i c i t y o f t h e organism i n in fancy and the pre-school per iod . The na tu re o f t h e experiences during these developmental stages shaped t h e course o f t h e i r development and formed i n par t the ap t i t udes and a t t i t u d e s r e l e v a n t t o school. As no ted above, t he re were no d i f f e rences i n IQ between groups; y e t , t h e c h i l d r e n r e c e i v i n g food supplements were h igher achievers as compared t o those who d id n o t rece ive supplementary foods.

M u l t i f o c a l i n t e r v e n t i o n s

The Mexico s tudy (Chavez & Mart inez, 1981) r a i s e s an impor tan t ques t ion i n connect ion w i t h t h e e f fec t i veness o f n u t r i t i o n i n te rven t ions . Are t h e e f f e c t s o f n u t r i t i o n supplementat ion more c l e a r l y apparent when t h e programme inc ludes o the r s o c i a l inpu ts , such as educat ion? The r e s u l t s f rom an i n t e r v e n t i o n study i n C a l i , Colombia a re d i r e c t l y r e l e v a n t t o t h i s issue. (McKay & McKay, 1983)

A paper pub l i shed i n 1978 (McKay, e t a l . 1977) focused on r e s u l t s f rom t h e behav iou ra l t e s t s admin is tered i n t h i s i n t e r v e n t i o n study. A n experiment was conducted which i nc luded groups o f c h i l d r e n e n r o l l e d i n the i n t e r v e n t i o n programme a t d i f f e r e n t ages, w i t h t h e f i r s t group beginning when they were 42 months o ld . E n t r y requirements i nc luded t h e presence o f m i l d t o moderate m a l n u t r i t i o n a t t he t ime t h e s tudy was i n i t i a t e d . A l l cases were se lec ted f rom neighbourhoods i n C a l i which were no ted f o r t h e i r extreme pover ty . Thus, i t al lowed f o r a s tudy o f how the age of enrolment i n t o t h e programme determined t h e magnitude o f t h e e f fec ts Of

t h e t reatment . The i n t e r v e n t i o n was based on a day-care cen t re and inc luded a sys- temat ic educat iona l programme f o r t h e c h i l d r e n p l u s h e a l t h care and d a i l y feeding; t h e programme operated about e i g h t hours a day, f i v e days a week.

There were f o u r d i f f e r e n t t reatment per iods, each o f a d i f f e r e n t d u r a t i o n and each beg inn ing a t a d i f f e r e n t p e r i o d i n t h e development o f t h e ch i l d ren . The f i r s t and longes t t reatment beqan when t h e c h i l d r e n were about 42 months o ld ; t he l a s t and s h o r t e s t t reatment began when t h e mean age o f t h e respec t i ve group was about 74 months. Two o the r groups were a l s o used f o r comparison; one f r o m . t h e same low- income group f rom which t h e t r e a t e d samples were selected, and the o the r f rom a high socio-economic group i n t h e c i t y o f C a l i .

Behavioura l t e s t i n g was conducted be fore and a f t e r t rea tment per iods. The t e s t s t h a t were admin is tered measured d i f f e r e n t aspects o f r e c e p t i v e and ex- p r e s s i v e language, memory, manual d e x t e r i t y and motor con t ro l , concept format ion, and l o g i c a l thinking, However, f o r comparative purposes an aggregate score f rom a l l t e s t s (descr ibed as genera l c o g n i t i v e ab i l i t y ) was used.

- 2 5 - By 87 months o f age the c h i l d r e n w i t h t h e longes t t rea tment had the h ighes t

t e s t performance among the t r e a t e d samples. Another impor tan t finding i s t h a t f o r a l l four groups the i n i t i a l g a i n i n t e s t performance a f t e r t h e i n i t i a t i o n o f t h e t reatment v a r i e d as a f u n c t i o n o f t h e age of t h e ch i ld ren . The younger the c h i l d a t the beginning o f t h e t reatment, t he g rea te r t h e i n i t i a l b e n e f i t s . The r e s u l t s f rom the ana lys i s o f t he c h i l d r e n ' s school performance i n d i c a t e s t h a t t h e number o f school f a i l u r e s f rom year t o year inc reased as t h e du ra t i on o f t ime t h e c h i l d r e n p a r t i c i p a t e d i n t h e programme decreased. S i m i l a r l y , t h e school grades o f t h e c h i l d r e n were n e g a t i v e l y r e l a t e d t o t h e age a t t he t ime o f t h e pre-school programme enrolment. The younger t h e c h i l d r e n en tered i n t o t h e programme (and the longer they stayed), t h e h ighe r t h e grades.

I t i s indeed d i f f i c u l t t o separate t h e c o n t r i b u t i o n s t h a t each o f t he i n p u t s o f t h i s programme had on t h e development o f the ch i ld ren . Yet, some in fe rences re levan t t o s o c i a l and educat iona l p o l i c y a re warranted. Once more t h e r e i s s t rong evidence o f t h e p l a s t i c i t y of t h e organism among young ch i l d ren . The course o f t h e i r growth and development was h e a v i l y determinedby the na tu re o f t h e experiences t h a t t he c h i l d r e n had.

A second in fe rence i s t h a t t h e age o f t h e c h i l d a t t h e t ime o f enrolment and t h e d u r a t i o n o f t h e programme made a d i f f e r e n c e i n terms o f t h e r e s u l t s . Thus, t he youngest c h i l d r e n who were exposed t o t h e programme f o r t h e l onges t p e r i o d o f t ime obta ined t h e h ighes t bene f i t s . ven t i on had s i g n i f i c a n t e f f e c t s on t h e performance and behaviour o f t he c h i l d r e n i n t h e school age period.. F i n a l l y , i t should b e underscored t h a t t h i s programme was comprised o f n u t r i t i o n , h e a l t h and educat ion inputs . It obv ious ly had a h ighe r y i e l d than programmes r e s t r i c t e d t o a s i n g l e input.

A t h i rd in fe rence i s that t h e pre-school i n t e r -

School feedinu Droararnmes

Are monofocal i n te rven t ions , such as school feeding, e f f e c t i v e among school age ch i l d ren? Conceivably, as the c h i l d grows o l d e r and becomes more d i f f e r e n t i a t e d , monofocal programmes may be more success fu l because they can be ta rge ted t o bas i c and s p e c i f i c developmental needs. A t i ssue here, there fore , i s what can be expected form school feed ing programmes ta rge ted t o n u t r i t i o n a l l y a t - r i s k ch i ld ren .

Evaluat ions i n developing coun t r i es o f t h e n u t r i t i o n a l and educat iona l b e n e f i t s o f school f eed ing programmes have been g e n e r a l l y unsuccessfu l (Levinger, 1983). A l a r g e number o f confounding v a r i a b l e s e n t e r i n t o p l a y i n eva lua t ions conducted w i t h i n the school and classroom s e t t i n g , which work aga ins t accurate evaluat ions. Evaluat ions o f t h e educat iona l b e n e f i t s o f school feed ing programmes i n the Un i ted States ( P o l l i t t , e t a l . 1978) have been cha rac te r i zed by an absence of s p e c i f i c hypotheses, ambiguity i n t h e d e f i n i t i o n o f var iab les , a l a c k o f da ta on the v a l i d i t y and r e l i a b i l i t y o f t h e measures used, and a l a c k o f cons ide ra t i on o f r e l e v a n t moderating var iab les . Poo l i ng the da ta f rom d i f f e r e n t s tud ies, however, l e d t o some t e n t a t i v e in ferences. I n connect ion w i t h shor t - term hunger (e.g. l a c k o f b reak fas t ) t h e da ta suggests t h a t t h i s p h y s i o l o g i c a l c o n d i t i o n has adverse e f f e c t s on emot ional behaviour, a r i t h m e t i c and read ing a b i l i t y , and p h y s i c a l work output . These f i n d i n g s agree w i t h those from exper imenta l s tud ies on the e f f e c t s o f shor t - term f a s t i n g on problem-solv ing behaviour. O n t h e o t h e r hand, t h e eva lua t ions o f long-term educa- t i o n a l b e n e f i t s o f school f eed ing have, on t h e average, f a i l e d t o y i e l d s t a t i s t i c a l l y meaningful f i nd ings .

One eva lua t i on on t h e educat iona l b e n e f i t s o f giving a school meal t o a c lass o f c h i l d r e n t h a t deserves p a r t i c u l a r a t t e n t i o n i s a s tudy conducted i n Jamaica (Powell, e t a l . 1983). Th i s study was c a r r i e d o u t i n a government run comprehensive school, s i t u a t e d i n a r u r a l mountainous area i n t h e i s land . came from poor f a r m i n g f a m i l i e s and ranged f rom 11 t o 17 years o f age. G i v i n g

The m a j o r i t y o f s tudents

- 26 -

break fas t t o a c lass o f school c h i l d r e n had a s i g n i f i c a n t e f f e c t on attendance and a r i t h m e t i c scores. These f i n d i n g s a re p a r t i c u l a r l y meaningfu l because t h e evalua- t i o n c o n t r o l l e d f o r t h e soc io-psychologica l va r iab les t h a t genera l l y confound t h i s type o f evaluat ion. The increased a t t e n t i o n which c h i l d r e n rece ive i n n u t r i t i o n a l i n t e r v e n t i o n programmes was r u l e d o u t by i n c l u d i n g a c o n t r o l group which was g i ven a syrup drink.

C r i t i q u e of t h e s tud ies

The s tud ies on t h e e f f e c t s o f e a r l y n u t r i t i o n supplementation on l a t e r beha- v i o u r a l development have faced a ser ious methodologica l d i f f i c u l t y i n measuring the t o t a l n u t r i e n t s i n t a k e o f t h e p a r t i c i p a n t s . o f t h e e x t e n t t o which t h e n u t r i t i o n a l supplement rep laced the u s u a l d i e t o f t h e p a r t i c i p a n t s . Thus, t h e d e f i n i t i o n o f t h e 'supplement' has been genera l l y imprecise.

There have been no accurate assessments

I n one s tudy (Wilson, 1981) t h e measurement o f t he supplement was f u r t h e r compl icated by t h e f a c t t h a t t h e food was d e l i v e r e d i n a feed ing s ta t i on . and c h i l d r e n who rece ived the supplement had t o v i s i t t h e s t a t i o n t o rece ive the supplement. Thus, t he re i s a r i s k o f a s e l f s e l e c t i o n b ias, so t h a t t he people who rece ived t h e supplements a l s o had some s o c i a l and behav ioura l c h a r a c t e r i s t i c s w h i c h made them d i f f e r e n t t o those who decided n o t t o rece ive the supplement. I n another study, (Chavez e t a l . 1981 , t h e i n t e r v e n t i o n probab ly i nc luded a p o t e n t s o c i a l i n t e r v e n t i o n i n a d d i t i o n t o t h e n u t r i t i o n supplementation, a l though t h e former was n o t programmed. The genera l i n t e r v e n t i o n ( s o c i a l and n u t r i t i o n a l ) may have a c t i v a t e d behaviours i n the parents o f t h e exper imental ch i l d ren , and i n o the r members o f t h e community, which i n turn cou ld have produced t h e e f f e c t s a t t r i b u t e d s o l e l y t o t h e n u t r i t i o n supplementation.

Mothers

The C a l i s tuay (McKay, e t al. 1983) had a compl icated research design, which r e q u i r e d l o n g i t u d i n a l comparisons o f d i f f e r e n t groups o f c h i l d r e n exposed t o the i n t e r v e n t i o n a t d i f f e r e n t developmental per iods. Moreover i t inc luded educat ion and h e a l t h serv ices i n a d d i t i o n t o t h e n u t r i t i o n i n te rven t ion . Accordingly, i t has been extremely d i f f i c u l t t o separate t h e e f f e c t s o f the var ious i n p u t s o f t he programme. Th is i n f o r m a t i o n would have s i g n i f i c a n t t h e o r e t i c a l and p r a c t i c a l impoEtance.

Conclusion

Eva lua t i on o f school feed ing programmes (Powell, e t a l . 1983 r' P o l l i t t , e t a l .

Of ten t h e n u t r i t i o n a l c h a r a c t e r i s t i c s o f t he meals p rov ided i n 1978) a re obv ious ly compl icated by t h e na ture o f t he i n t e r v e n t i o n i t s e l f and i t s e c o l o g i c a l context . school do n o t meet the n u t r i t i o n a l needs o f t h e school ch i ld ren . Moreover, i n the school o r classroom s e t t i n g t h e r e a re a number o f v a r i a b l e s associated w i t h b o t h the r e c i p i e n t s and t h e i n s t i t u t i o n s which are l i k e l y t o i n t e r a c t w i t h t he n u t r i t i o n programme and determine i t s outcome. Reviews o f t h e s tud ies on the educat ional and c o g n i t i v e e f f e c t s o f school feed ing programmes ( P o l l i t t , e t a l . 1978; Levinger, 1983) have n o t been ab le t o demonstrate w i thou t any reasonable doubt, t h a t these programmes do indeed b e n e f i t t h e p a r t i c i p a n t s . O n t he o the r hand, i t must be recognized t h a t t h e l ack o f evidence may be due t o t h e i nhe ren t complex i t ies o f t h e evaluat ion, and n o t due t o a genuine l a c k o f e f fec ts .

The s tud ies i n Mexico (Chavez e t a l . 1981) and Ca l i , Colombia (McKay e t a l . 1983) p resent conc lus ive evidence t h a t t h e developmental course o f c h i l d r e n i s shaped by t h e na ture o f t h e developmental experiences they face. Both s tud ies prove t h a t improvements i n t h e q u a l i t y of l i v i n g among n u t r i t i o n a l l y a t - r i s k c h i l d r e n i s conducive t o t h e a c q u i s i t i o n o f a t t i t u d e s and ap t i t udes which a r e necessary i n t h e con tex t o f t h e fo rn ia l educat iona l system. I t i s apparent, h,owever, t h a t nutri- t i o n i n t e r v e n t i o n s p e r se, as monofocal programmes, a re n o t as successfu l as those m u l t i f o c a l i n t e r v e n t i o n s which add educat iona l and h e a l t h serv ices t o a good d i e t .

- 2 7 - Conceivably, more i n t e g r a t i v e approaches t o school feed ing where t h e s p e c i f i c deve- lopmental needs are taken i n t o account may l e a d t o a g rea te r success i n t h i s type o f i n t e r v e n t i o n d i r e c t e d t o ch i l d ren .

- 28 -

REFERENCES

CHAVEZ, A. & MARTINEZ, C., School performance o f supplemented and unsupplemented c h i l d r e n f r o m a poor r u r a l area. In: N u t r i t i o n i n H e a l t h and Disease and I n t e r n a t i o n a l Development; Symposia f r o m t h e X I I I n t e r n a t i o n a l Congress o f N u t r i t i o n . 393-402, New Yoxk, N.Y., A lan R. L i s s , Inc. 1981.

JOOS, S.K. & POLLITT, E. E f f e c t s o f supplementation on k h a v i o u r a l development i n c h i l d r e n up t o t h e age o f t w o years: a comparison o f f o u r s tud ies . In: Brozek, J. & Schurch (Eds.) C r i t i c a l Assessment o f Key Issues i n Research on M a l n u t r i t i o n and Behaviour. The N e s t l e Foundation: Lausanne, Switzer land, 1984.

LEVINGER, B., School f eed ing programmes i n l e s s developed count r ies : an ana lys i s o f a c t u a l and p o t e n t i a l impact. O f f i c e o f Eva lua t ion , Bureau f o r Food and Voluntary A i d , Agency f o r I n t e r n a t i o n a l Development. Washington, D.C. U n i t e d States, 1983.

McKAY A., & McKAY H., Pr imary school progress a f t e r pre-school experience: t roub le - some issues i n t h e conduct o f follow-up research and f i n d i n g s f rom t h e C a l i , Colombia S t u d y . In: Prevent ing school f a i l u r e : t h e r e l a t i o n s h i p between pre-scf iool and p r imary education, Proceedings o f a workshop on pre-school research h e l d i n Bogota Colombia, 26-29 May 1981, 36-41, Ottawa, Canada, I n t e r n a t i o n a l Development Research Centre: IDRC P u b l i c a t i o n No. 172e, 1983.

McKAY, H. SINISTERRA, L., MCKAY, A., GOMEZ, H. & LLOREDA, P. I m p r o v i n g c o g n i t i v e a b i l i t y i n c h r o n i c a l l y dep r i ved ch i l d ren . Science, 1977, 2 0 0 , 270-278.

POLLITT, E., GERSOVITZ, M. & GARGIULO, M. Educat ional b e n e f i t s o f t h e U n i t e d S ta tes schoo l f eed ing programme: a c r i t i c a l rev iew o f t h e l i t e r a t u r e . American J o u r n a l o f P u b l i c Heal th, Washington, D.C. 68(5) , 1978, 477-481.

POWELL, C., GRANTHAN-McGREGOR, S. 8, ELSTON, M., A n e v a l u a t i o n o f giving t h e Jamaican government schoo l meal t o a c lass o f ch i l d ren . Human N u t r i t i o n : C l i n i c a l N u t r i t i o n , Westport, Connect icut , 37C, 1983, 381-388.

WILSON, A.B., L o n g i t u d i n a l a n a l y s i s o f d i e t , p h y s i c a l g r o w t h , v e r b a l development, and schoo l performance. In: Malnourished c h i l d r e n o f t h e r u r a l poor, p. 39. Balderston, J.B., Wilson, A.B., F r e i r e , M.E. & Simonen, M.S. (eds) Boston, Massachusetts, A u b u r n House Pub l ish ing , 1981.

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V. CONCLUS IONS

Throughout t h e develop ing w o r l d 'educat iona l wastage' represents one o f t h e

Educat iona l wastage g e n e r a l l y r e f e r s t o t h e number o f c h i l d r e n who l a r g e s t and most s i g n i f i c a n t educat iona l problems, i n v o l v i n g a high human and c a p i t a l cost . repeat a grade, o r who drop o u t o f school. R e p e t i t i o n i s de f i ned as t h e s tudent who, throughout a g i ven school ye.ar, remains i n t h e same c lass and performs t h e work o f the prev ious year. Dropping o u t i s de f i ned as t h e s tudent l e a v i n g b e f o r e t h e end o f the f i n a l year of t h e educat iona l course i n which he i s enro l led . The g rea tes t problem o f 'wastage' i s found i n A f r i c a , where i n some coun t r i es 30 p e r cent o r more of t h e i r c h i l d r e n (boys and g i r l s ) i n pr imary educat ion a r e de f i ned as repeaters. I n 1980 among Engl ish-speaking coun t r i es i n A f r i c a , t h e average l e v e l o f r e p e t i t i o n was around 6.1 p e r cent; w h i l e f o r French-speaking coun t r i es the average was about 22.6 p e r cent. There are a l s o a l a r g e number o f South and Cen t ra l American coun t r i es where 1 5 p e r cent o r more o f t h e i r p r imary school s tudents a re repeaters ( i .e . Honduras, Guatamala, Dominican Republ ic, Peru, B r a z i l ) (Unesco D i v i s i o n o f S t a t i s t i c s i n Education, 1984).

The f o l l o w i n g t a b l e p resents t h e coverage and median percentage o f r e p e t i t i o n s i n pr imary education.

- ~ ~~~

Coverage and median percentage o f r e p e t i t i o n s i n p r imary educat ion, boys and g i r l s

Coverage' Number o f Percentage Median 1980 coun t r i es v a r i a t i o n i n percentage o f

% number o f repeat e r s repeaters

. ~ ~~

TOTAL

A f r i c a

62.8 121 0.0 - 46.6 10

60.1 42 0.0 - 46.6

L a t i n America and t h e Caribbean 89.4 24 3.6 - 25.8

As ia and Oceania 46.4 3 2 0.0 - 17.8

16

12

8

Europe and USSR 86.6 23 0.0 - 19 2

1. Representativeness of t h e coun t r i es examined w i t h re fe rence t o t o t a l enrolments i n pr imary education.

Ev iden t l y , t h e human and c a p i t a l cos t o f educat iona l wastage v a r i e s accord ing t o a number o f f ac to rs . The educat iona l i m p l i c a t i o n s o f dropping o u t a re s i g n i f i - c a n t l y d i f f e r e n t between those c h i l d r e n who l e a r n t o read and w r i t e be fo re they leave school, f rom those who a re i l l i t e r a t e . L ikewise, t h e occupat iona l fc i ture o f c h i l d r e n who drop o u t a t t h e beg inn ing o r a t t h e end o f t h e pr imary school p e r i o d w i l l a l so be d i f f e r e n t . I n any event, coping with educat iona l wastage r e q u i r e s an in-depth ana lys i s of i t s r o o t s - o f i t s d i s t a l and p rox ima l causa l f a c t o r s - so t h a t r e l e v a n t p o l i c i e s can remediate it, i f n o t p reven t it.

- 3 0 -

A n a d d i t i o n a l s i g n i f i c a n t problem pa r t l y r e l a t e d t o educat iona l wasting, i s t h a t o f c h i l d r e n who never e n r o l l i n the fo rmal educat iona l system. E i t h e r because schoo l ing i s n o t ava i l ab le , o r i t i s t o o f a r , o r because o f economic l i m i t a t i o n s o f t h e fami ly , o r o f c u l t u r a l p r a c t i c e s , some c h i l d r e n (most ly g i r l s ) f a i l t o go t o school a lhogether. Thus, i n these cases, a ser ious obs tac le i s p laced i n f r o n t o f t h e s o c i a l and economic development of those c h i l d r e n even be fo re they have reached adolescence.

A subs tan t ive body o f l i t e r a t u r e has examined t h e determinants u f school per- formance, w i t h a p a r t i c u l a r emphasis on school wastage. As i n d i c a t e d before, these determinants vary, and they tend t o d i f f e r between developed and developing count r ies . I n t h i s l a t t e r case, economic f a c t o r s genera l l y p l a y a s a l i e n t r o l e . W i t h i n t h i s l i t e r a t u r e the re has been a s e l e c t i v e omission o f n u t r i t i o n and h e a l t h as p o t e n t i a l determinants o f school performance and wastage. Th is omission i s s u r p r i s i n g because, i n some cases, the l i m i t a t i o n s imposed by n u t r i t i o n a l f a c t o r s a re dramatic, such as i n vitamin A de f i c iency .

Thismonographreviewed th ree main areas o f t h e r e l a t i o n s h i p between n u t r i t i o n and education: (a) t h e e f f e c t s o f e a r l y u n d e r n u t r i t i o n on subsequent i n t e l l e c t u a l f u n c t i o n and school progress; (b) t h e r e l a t i o n s h i p between t h e n u t r i t i o n a l s t a t u s o f t he s tudent and school progress; ( c ) t he educat ional consequences o f n u t r i t i o n i n t e r v e n t i o n programmes. Most s tud ies reviewed w i t h i n each o f these ca tegor ies have ser ious methodologica l problems; conc lus ive in fe rences on t h e b a s i s o f any one o f these s tud ies i s t he re fo re unwarranted. However, i t i s recognized t h a t t he s tud ies reviewed genera l l y agree o f t h e i r f i nd ings . This convergence o f r e s u l t s d e p i c t s a p i c t u r e t h a t shows n u t r i t i o n as an impor tan t determinant o f educat iona l performance, and as a p o t e n t resource t o decrease 'educat iona l wastage'. The f o l l o w i n g a re conclus ions j u s t i f i e d by t h e da ta c u r r e n t l y ava i lab le .

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The i n t e l l e c t u a l f u n c t i o n during school age, and the educat iona l progress o f c h i l d r e n w i t h a h i s t o r y o f ea r l y , severe and chron ic m a l n u t r i t i o n born i n t o cond i t i ons o f severe s o c i a l and economic d e p r i v a t i o n are a t high r i s k . It i s t o be expected t h a t t he c h i l d r e n w i l l have low school achievement, w i l l t end t o repea t grades, and main ta in a high drop-out r a t e .

The c o n t r i b u t i o n t o educat iona l wastage by undernourished c h i l d r e n w i l l depend on t h e prevalence o f severe m a l n u t r i t i o n i n the country. Th i s r e l a t i o n s h i p w i l l be mainta ined unless the re a re s p e c i f i c compensatory programmes d i r e c t e d t o remediate the e f f e c t s o f u n d e r n u t r i t i o n p r i o r t o t h e enrolment o f c h i l d r e n i n school.

The h ighes t educat iona l r i s k i s found among those c h i l d r e n whose e a r l y , severe and chron ic u n d e r n u t r i t i o n coex is ted w i t h a p h y s i c a l environment conducive t o a high inc idence o f communicable diseases, and a s o c i a l en- v i ronment t h a t f a i l s t o p rov ide oppor tun i t i es f o r l ea rn ing . The lowest r i s k i s found among c h i l d r e n w i t h a s i m i l a r h i s t o r y but subsequently exposed t o a s a l u t a r y environment t h a t stimu1ated.th.e c h i l d ' s e-ducational p o t e n t i a l and meets bas i c soc ia l -emot ional needs. The magnitude o f t he '. c o g n i t i v e d e f i c i t s l i k e l y t o f o l l o w an ea r l y , severe and chronic ma lnu t r i - t i o n cannot be d e f i n i t i v e l y establ ished. E a r l y and chron ic m a l n u t r i t i o n i s n o t a s u f f i c i e n t c o n d i t i o n f o r l a t e r i n t e l l e c t u a l d e f i c i t . Many i n t e r - vening v a r i a b l e s en te r i n t o p l a y (such as the na tu re o f t he s o c i a l environ- ment) t o determine the na tu re o f t he f i n a l developmental and educat ional outcome.

M u l t i f o c a l i n t e r v e n t i o n programmes t h a t combine n u t r i t i o n supplementation, h e a l t h care, and educat ional s t i m u l a t i o n have s i g n i f i c a n t developmental impact. Ch i ld ren w i t h a h i s t o r y o f moderate t o severe ma lnu t r i t i onexposed t o these programmes beg inn ing as l a t e as 42 months o f age have had

- 3 1 -

subs tan t ive improvement i n c o g n i t i v e performance. T h e i r school achievement and progress has a l s o been s i g n i f i c a n t l y h ighe r than c h i l d r e n who were b e t t e r o f f n u t r i t i o n a l l y i n e a r l y l i f e , but were n o t exposed t o t h e i n t e r - v e n t i o n programme. The e a r l i e r t h e i n t e r v e n t i o n and t h e longer the d u r a t i o n o f m u l t i f o c a l programmes, t h e g rea te r t he developmental and educat iona l b e n e f i t s accrued. Thus, i t i s expected t h a t pre-school m u l t i - f a c t o r i a l programmes w i l l have a s i g n i f i c a n t e f f e c t on the decrease o f school wastage among popu la t i ons where m a l n u t r i t i o n i s endemic and the re i s a high inc idence o f communicable diseases.

5. The remedia l o r p reven t i ve e f f e c t s o f monofocal n u t r i t i o n supplementation i n t e r v e n t i o n programmes during e a r l y l i f e on the i n t e l l e c t u a l d e f i c i t s assoc iated w i t h e a r l y chron ic u n d e r n u t r i t i o n a re quest ionable. N u t r i t i o n supplementat ion ta rge ted t o pregnant and l a c t a t i n g women, and t o i n f a n t s and young c h i l d r e n have shown no e f f e c t s on the menta l development o f c h i l d r e n once they reach school age. Accordingly, t h e c o n t r i b u t i o n t h a t t h i s moda l i t y o f i n t e r v e n t i o n w i l l make on educat iona l improvement i s p robab ly n e g l i g i b l e .

6 . I r o n d e f i c i e n c y anemia among school s tudents represents an impediment t o learn ing . Th is evidence has educat iona l i m p l i c a t i o n s which a re dramatic, because o f t he l a r g e number o f c h i l d r e n l i k e l y t o be anemic b o t h i n deve- l o p i n g and developed count r ies . It has been est imated t h a t t he re are about 1.3 b i l l i o n people who a re anemic around t h e wor ld . The e f f e c t s o f i r o n d e f i c i e n c y on c o g n i t i v e f u n c t i o n are r e v e r s i b l e . I r o n r e p l e t i o n therapy among i r o n d e f i c i e n t anemic pre-adolescent c h i l d r e n r e s u l t e d i n s i g n i f i c a n t improvements i n school achievement measures. The under l y ing mechanisms whereby i r o n d e f i c i e n c y a f f e c t s l e a r n i n g a r e n o t known. Impe- diment i n l e a r n i n g does n o t necessa r i l y mean, however, t h a t h ighe r c o g n i t i v e processes have been a f fec ted . I r o n d e f i c i e n c y i s l i k e l y t o a f f e c t t he l e v e l o f a le r tness (arousal ) o f ch i l d ren , which i n turn a f f e c t a t t e n t i o n and, there fore , l ea rn ing .

7 . Among wel l -nour ished c h i l d r e n a n ine teen t o twenty hour f a s t i n g p e r i o d a f f e c t s a t t e n t i o n , and the capac i t y t o so lve problems o f v isua l -perceptua l o rgan iza t ion . There i s a l s o suggest ive evidence f rom eva lua t ions o f school feed ing programmes i n developed coun t r i es t h a t n o t taking b reak fas t a f f e c t e d performance i n read ing and a r i t h m e t i c tes ts .

8. Ch i ld ren w i t h low c a l o r i e i n t a k e over l o n g per iods o f t ime reach a s t a t e o f energy balance through reduc t ions i n a c t i v i t y l e v e l . A c t i v i t y i s a key mechanism whereby c h i l d r e n explore, and r e l a t e t o t h e i r s o c i a l and p h y s i c a l environment. Thus, reduc t ions i n a c t i v i t y represents a l oss o f s i g n i f i c a n t o p p o r t u n i t i e s f o r learn ing . There i s no i n f o r m a t i o n regard ing the cogn i t i ue e f f e c t s t h a t may r e s u l t , among undernour ished ch i l d ren , f rom go ing t o school w i t h o u t hav ing had a meal a f t e r an ove rn igh t f a s t . Compensatory mechanisms may p r o t e c t c o g n i t i v e f u n c t i o n f rom t h e adverse e f f e c t s o f low c a l o r i c i n t a k e during school hours, among c h i l d r e n who a re used t o t h i s type o f feed ing schedule.

9. There i s s t rong suggest ive evidence t h a t school feed ing programmes i n developing coun t r i es r e s u l t i n an increased attendance among r e c i p i e n t s . Th i s inc rease may have s i g n i f i c a n t educat iona l b e n e f i t s i n the l ong run as i t ensures t h e exposure o f t h e s tudent t o the m a t e r i a l s taught i n school There i s no conclus ive i n f o r m a t i o n f rom developing coun t r i es that school feed ing programmes (b reak fas t o r lunch) has s p e c i f i c educat iona l bene f i t s , such as improvements i n achievement measures .or h i g h e r concentrat ion.

- 3 2 -

The evidence presented throughout t h i s monograph, and t h e conclusions t h a t have been advanced i n d i c a t e t h a t i t i s impera t ive t o i n c l u d e n u t r i t i o n as a de ter - minant o f schoo l performance and achievement. E a r l y m a l n u t r i t i o n and poor nutr i- t i o n a l s t a t u s among students can, and w i l l have s i g n i f i c a n t adverse e f f e c t s over school progress, and c o n t r i b u t e s i g n i f i c a n t l y t o school wastage. C h i l d r e n whose l e a r n i n g i s slow and have d i f f i c u l t i e s master ing school m a t e r i a l a r e candidates w i t h high chances o f repea t ing grades and dropping o u t e a r l y from school.

Demands f o r d e f i n i t i o n of t h e s p e c i f i c mechanisms through which e a r l y severe and ch ron ic m a l n u t r i t i o n a f f e c t s subsequent school performance, o r f o r t he d e f i n i t i o n o f t h e process through which i r o n d e f i c i e n c y a f f e c t s a t t e n t i o n cannot be p r e s e n t l y s a t i s f i e d . The i n f o r m a t i o n i s n o t a v a i l a b l e , and the re i s no way a t p resent o f assessing accu ra te l y t h e r i s k s invo lved. However, i t i s necessary n o t t o equate r i s k assessment w i t h r i s k management. The data a v a i l a b l e i s conc lus ive t o demonstrate t h a t t h e p r o t e c t i o n o f t h e c h i l d ' s n u t r i t i o n a l s ta tus d u r i n g h i s e a r l y fo rmat ive years and during t h e school p e r i o d w i l l r e s u l t i n a b e t t e r student, and w i l l s i g n i - f i c a n t l y decrease t h e human and c a p i t a l costs of school wastage.

- 3 3 -

APPENDIX

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