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The Vitamins
David L. Gee, PhDProfessor of Food Science and Nutrition
Central Washington UniversityFCSN 245 - Basic Nutrition
Dietary Supplement Use (USA)
$ 4,300,000,000 for vit/min in 1995$ 1,400,000,000 for herbs35-40% adults regular users
females > males 66% multi-vit/min 37% vitamin C 19% vitamin E Calcium supplements
Dietary Supplement Use: Pros
Supplements dietary deficiencies calcium folic acid
Amounts used in some studies not attainable with dietary sources antioxidants
Relatively low cost
Dietary Supplement Use: ConsFalse sense of security
folic acid and pregnancyDoes not contain all potentially useful chemicals in
foods Example: compounds found in plants that may be health
promoting (phytochemicals)Toxicity almost only due to supplement useCosts significant
low income Heavy users of supplements (athletes) Certain supplements are expensive
Chondroitin sulfate – bone/cartilage: $30-50/moSAMe – depression: $40-50/mo
Exam 3 – Tuesday, March 6
Proteins and Amino Acids (chap 6) EAA, RDA, functions, athletes Genetically modified foods (p 472-480) Vegetarian diets Protein quality Protein deficiency (kwashiorkor/marasmus)
Energy and Weight Loss (chap 9) Energy, TEE, BMR, factors affecting BMR, activity, TEF Calorimeters (bomb, direct, indirect) Weight loss, obesity risks, QOL, prevalence, high risk groups Healthy weight, assessment
Calculate BMI, know cutpoints for blood pressure, sugar, lipids Dietary approaches (Balanced, Lo-Carb, restrained CHO, non-diet Exercise Drugs/Surgery
Vitamin & Mineral Deficiency:A Global Progress Report
UNICEF, 2004
80 developing countries studied Accounts for 80% of world population
1/3rd of world population do not reach their physical and intellectual potential because of vitamin/mineral deficiency
Vitamin & Mineral Deficiency:A Global Progress Report
UNICEF, 2004
Vitamin A deficiency40% of children <5yrs with mild to
severe deficiencyCompromised immune deficiencyblindnessstunted growth
Contributes to 1 million deaths of young children/yr
A Solution: supplementation with beta-carotene, 2x/yr, fortification of foods
Vitamin & Mineral Deficiency:A Global Progress Report
UNICEF, 2004
Iodine deficiencyGoiter: enlarged thyroid gland, lethargy
Cretinism: severe mental and physical retardation in infants of deficient mothersReduces IQ by 10-15 points80% of developing countries have goiter rates
of > 10% A Solution: iodized salt (use declined from
75% to 65% in last decade!)
Myxedematous endemic cretinism in the Democratic Republic of Congo : Four inhabitants aged 15-20 years : a normal male and three females with severe longstanding hypothyroidism with dwarfism, retarded sexual development, puffy features, dry skin and hair and severe mental retardation.
Woman with iodine deficiency resulting In a goiter.
Vitamin & Mineral Deficiency:A Global Progress Report
UNICEF, 2004
Iron deficiencyAnemia: fatigue, apathy in adults, poor
academic performance in children (7-10pt drop in IQ) ~45% of children between 6mo-2 yrs
20 countries over 70% A solution
Supplementation (bad taste, constipation)Fortification
• Salt with iodine and iron• Vitamin/mineral mixes added to foods• Fortified foods
The Discovery of Vitamins
The Germ Theory of Disease Scurvy: Disease
of sailors Beri-Beri:
Disease of poor Asians
The Discovery of Vitamins
The Germ Theory of Disease Rickets: Disease of
poor Northern European children
Pellagra: Disease of poor corn eating cultures
The Discovery of VitaminsThe Vitamin Theory of Disease
Scurvy: Disease of sailorsVitamin C deficiency
Beri-Beri: Disease of poor AsiansThiamin deficiency
Rickets: Disease of poor Northern European childrenVitamin D deficiency
Pellagra: Disease of poor corn eating culturesNiacin deficiency
Vitamins: Definition
Organic compound found in foodsRequired in small amountsRequired in the diet (dietary
essential)Proven to be required for health,
growth, and reproduction deficiency syndrome identified
Vitamin NomenclatureFat soluble “A” & Water soluble “B”“Vital amines”
vitamines = vitaminsVitamin B “complex”
collection of water soluble vitamins that function as enzyme co-factors
Vitamin CVitamins D and EMistaken Vitamins
Fat and Water Soluble Vitamins
Fat Soluble Vitamins (A, D, E, K)
Soluble in lipids and solventsExcess stored and not excretedExcess may be toxicDeficiency slow to develop
Fat and Water Soluble Vitamins
Water Soluble VitaminsB vitamins, CSoluble in waterexcess excreted in urine, little
storedgenerally less toxicdeficiency develops quickly
General Functions of Vitamins
Hormones Vitamin D
calcium homeostasis Vitamin A
cell division and development
General Functions of Vitamins
Non-specific chemical reactions
Vitamin E antioxidant
Vitamin C chemical reducing agent
General Functions of Vitamins
Coenzymes or Cofactors chemicals that assist enzymes to function as catalystsB vitamins Vitamin C, A, K
Vitamin A: types and sources
Retinoids retinol, retinal, retinoic acid animal foods, milk fortification
Carotenoids beta-carotene plants vitamin A precurser
Vitamin A: functions
Visual pigment: rhodopsin “night blindness”
Maintenance of epithelial cells regulation of keratin protein synthesis Xeropthlamia intestinal malabsorption
Bone and Immune System Development
Vitamin A: Deficiency
Common in developing countries 3 million children with severe
deficiencyblindness, poor growth and appetite
275 million children with mild deficiencyimpaired immunity
Vitamin A: Toxicity
10 times RDA chronically100 times RDA acute dosehair loss, joint pain, birth defectscarotenoids are non-toxictoxicity due to vitamin
supplement overdose
Vitamin D: Types and Sources
Dietary sources: animal foods, fortified milk
Human Synthesis of Vitamin DSkin: cholesterol + sunlight
“Sunshine Vitamin” – UV-B rays Vitamin D3
5-10 minutes, arms and legs, mid-day sun
Liver & Kidney for activation 1,25-di-OH-D3
Final Exam – Winter 2007
Tuesday, March 15, noon25% vitamins and minerals
Lecture materials General info on vitamins/mineralsDeveloping world vitamin/mineral deficiencies
Required readingChapter 7 (vitamin C ; vitamin A/carotenoids )Chapter 8 (nutrients involved in bone health)Chapter (iron ; folate & B-12 )
Final Exam – Winter 2006
75% comprehensive “questions that you should know
the answers to one or two years from now.”Study class notesReview old exams
Vitamin D: Functions
Helps regulate blood calcium levels When blood calcium levels are low,
vitamin D (and other hormones):Increases dietary calcium absorptionDecreases urinary calcium excretionIncreases bone calcium mobilization
Vitamin D: Deficiency
Rickets bone deformities in children
Osteomalacia weak bones due to low
calcium content Vitamin D deficiency Calcium deficiency multiple pregnancies
Vitamin D: Toxicity
5 times the RDA chronically calcification of soft tissue toxicity due to excessive vitamin supplementation
Calcium
FunctionsBone Structure (99%)Regulator of Metabolism (1%)
nerve impulse transmission muscle contraction blood clotting etc.
Calcium
Regulation of Blood Calcium 10 mg/dl of blood
hypocalcemia & hypercalcemia abnormal muscle cramping nerve irritation
Controlled by: vitamin D, parathyroid hormone, calcitonin
Calcium RDA
1998 RDA’s (AI) 1300 mg/d : children & teens 1000 mg/d : adults 1200 mg/d : older Americans
Usual intakes are low
Osteoporosis
Brittle, weak bones due to loss of total bone mass (minerals and protein)
Prevalence 11% of > 65 yrs 22% of > 65 yrs in 20 yrs 24 million fractures/yr 200,000 hip fractures, 1/6 fatal
3D Visualization of data obtained by x-ray microtomography of the bone structure of the vertebrae of a 50 year old (left) and a 70 year old (right)
This graph shows rates in the USA in 1984-87, adapted from Jacobsen, SJ in American J Public Health 80:872, 1990.
An illustration of the consequence of osteoporosis on the spinal column.
Elderly woman with dowagers hump, a marked abnormal curving of the spine caused by osteoporosis
Other osteoporosis fact:National Osteoporosis Foundation - 2003
10 million with osteoporosis 18 million with low bone density
1 in 2 women will develop osteoporosis sometime in their life (1 in 8 men)
Osteoporosis
Risk FactorsGenetics
Family History Ethnicity Caucasian > Asian > Blacks
Osteoporosis
Risk FactorsGender
associated with declines in estrogen production
post-menopause anorexia, female athletes
Undertreatment of Osteoporosis in Men with Hip Fracture.
Arch. Int. Med. (Oct. 2002)
10 million Americans with osteoporosis 2 million are men
Of 110 men hospitalized with hip fracture 4.5% received treatment for osteoporosis 1 year mortality was 32% Average age 80 yrs
Of 253 women hospitalized with hip fracture 27% received treatment for osteoporosis 1 year mortality was 17% Average age 81 yrs
Osteoporosis
Risk FactorsChronic Calcium Deficiency
Lack of Exercise
Prevention of Osteoporosis
ExerciseDietary Calcium“Rule of 300”
300 mg/d from plant sources 300 mg/d from each serving of dairy
Prevention of Osteoporosis
Other factors that may increase calcium loss high caffeine intake high protein intake high alcohol intake cigarette smoking
Prevention of Osteoporosis
Calcium SupplementsCalcium carbonate
least expensive Tums poor absorption
Calcium citrate/malate (CCM) expensive, well absorbed
Prevention of Osteoporosis
Adequate amounts of vitamin D avoid excesses
Hormonal replacement in high risk women
http://www.mhhe.com/biosci/ap/mediacentral/nutrition_animations/osteoporosis_final.swf
Folic Acid
DRI (RDA): 1998 400 ug/d (180-200 old RDA) 600 ug/d pregnancy (400)
Typical folate intake: 200 ug/dDietary Sources
foliage: fruits & vegetables
Folic Acid
Functions“single carbon metabolism” DNA synthesis (cell division) other reactions
Folic Acid
DeficiencyMegaloblastic Anemia
large abnormal red blood cellsElevated blood homocysteine
CHD risk factor
Folic Acid
DeficiencyNeural Tube Defects
spina bifida - lower body paralysis
required early in pregnancyGrain fortification (1998)
will add 100-200 ug/d to diet
Vitamin B-12
Cobalamine contains cobaltDRI (1998) : 2.4 ug/d (old 2 ug/d)Dietary sources:
animal foods fortified cereals
Vitamin B-12
Functions“single carbon isomerization” synthesis of DNA (folate interaction)
nerve fiber sheath synthesis
Vitamin B-12
DeficiencyPernicious Anemia
megaloblastic anemia nerve injury peripheral weakness and numbness progressive degeneration to death concern among the elderly
Vitamin B-12
Digestion and AbsorptionRequires functioning stomach “intrinsic factor protein” acid production
B-12 and Folic Acid
Excessive folic acid can mask nerve degeneration of pernicious anemia
FDA regulates dosage of folate supplements
FDA limited amount of folate fortification in grains
Nutritional Antioxidants
Oxidative Tissue InjuryOxygen free radicals
unpaired electrons superoxide O2
-.
hydroxy free radical OH.
hydrogen peroxide
Oxidative Tissue Injury
Causes chain reactive damage to:
Cell membranes (hi PUFA)ProteinsDNA
Oxidative Tissue Injury
Associated with:Coronary Heart Disease
oxidized LDL-cholesterolCarcinogenesisChemical ToxicityAuto-immune dieseasesAging
Sources of Oxygen Free Radicals
Normal energy metabolismnutrient + O2 --> CO2 + H2O + energyElectron transport system
O2 --> H2O + energy
but: O2 --> O2-. --> H2O + energy
Sources of Oxygen Free Radicals
D-amino acid metabolism D-AA --> C-skeleton + ammonia +
H2O2
Metabolism of foreign chemicals drugs, pesticides, toxins, etc...
Ozone, nitrogen oxides, UV light, smoke, radiation, etc...
Cellular Antioxidants
Antioxidant EnzymesCatalase (iron)
removes hydrogen peroxidesSuperoxide Dismutase (Cu,
Zn) removes superoxide radicals
Cellular Antioxidants
Antioxidant EnzymesGlutathione Peroxidase (Se)
removes peroxidesMineral supplements are ineffective and may be toxic
Cellular Antioxidants
Nutritional AntioxidantsVitamin E Carotenoids and other plant phytochemicals
Vitamin C
Vitamin E
TocopherolsDietary sources:
widespread, highest in plant oilsDeficiency:
rare in adults premature infants: hemolytic
anemia
Vitamin E
Function: free radical scavenger in membranes
RDA: 8-10 mg/d“Research dosages”: 400-800 mg/dToxicity: rare, may be non-toxic
below 1000 mg/d
Plant Phytochemicals
Beta-carotene & carotenoidsPlant polyphenols
garlic green tea grape skins cruciferous vegetables
Antioxidants with “specific niches”
Vitamin C
Ascorbic AcidFood Sources
fruits vegetables
Deficiency: Scurvy poor wound healing impaired immune system
Vitamin C Functions
Antioxidant water soluble free radical scavenger
Collagen synthesis connective tissue protein
Synthesis of neurotransmitters, thyroxine, etc.
Aids in absorption of dietary iron
Vitamin C
RDA : 60 mg/dRDA (smokers): 100 mg/dtypical intake 100 mg/d“Effective research dosages” : 100-500 mg/d
Vitamin C
“Toxicity” > 1000 mg/ddiarrheakidney stonespromotes “iron overload” toxicityInterfers with important lab tests
blood in stools (colon cancer) urinary and blood glucose (diabetes)
Iron
Functions:HemoglobinMyoglobinIron enzymes
catalase electron transport system
Iron Deficiency
Iron deficiency anemia fewer, smaller, paler red blood cells fatigue
5-10% of US premenopausal women
up to 40% of population in developing countries
Iron Deficiency CausesBlood loss
menstrual blood loss parasites and bleeding ulcerations
Inadequate dietary intakeRDA men = 10 mg/dRDA women = 15 mg/dUS usual intake 6 mg/1000 Cal
Dietary Sources of IronHeme Iron
meats (Hb & Mb) 20-30% absorbed
Non-heme Iron plants inorganic iron 1-10% absorbed vitamin C increases absorption iron cookware
Iron Overload Toxicity
Children (accidental poisoning) Men and post-menopausal
womenGenetic “defect”
improved iron absorptionExcess iron is a pro-oxidant.
oxidized LDL-C tissue injury
Iron Overload Toxicity
May occur in 10% of menTreatment
avoid iron containing supplements
avoid excess vitamin C supplements
bleeding or blood donation