[Reprinted from The Medical News, December 30, 1893.]

THE ROLE OF LACTIC ACID IN GASTRICDIGESTIOA

ALLEN A. JONES, M.D.,CLINICAL INSTRUCTOR IN MEDICINE AND INSTRUCTOR IN PRACTICE,

MEDICAL DEPARTMENT, UNIVERSITY OF BUFFALO.

Lactic acid is present in the stomach under nor-mal conditions from thirty to forty minutes aftera test-meal composed of a roll and water or ofchopped lean beef, dry bread, and water. At theexpiration of that time lactic acid should entirelydisappear from the stomach-contentsand free hydro-chloric acid alone should prevail. During the firstthirty or forty minutes after meals the digestion ofstarches and albuminoids progresses quite rapidly,as may be proved by finding the middle-productsand end-products of gastric digestion present, sothat the presence of free lactic acid does not pro-hibit digestion.

As soon as food enters the healthy stomach thesecretion of hydrochloric acid is excited and itincreases in amount until the production of lacticacid is checked. The exact origin of lactic acid inthe healthy stomach is still a matter of debate. Itmay arise wholly from fermentation, or from thecombination of some food-product with a secretion

1 Read before the Buffalo Academy of Medicine, Novemberx 4) 1893.

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from the gastric glandules, or from the gastricmucosa as a distinct secretion, although electricstimulation of the gastric glandules excites the se-cretion of hydrochloric acid and not of lactic acid.I think it arises largely from fermentation of thefood, as its amount is usually proportionate to theamount of starchy, saccharine, and milk foodstaken.

I have, however, many times found lactic acidpresent in the stomach-contents two, three, or morehours after the ingestion of lean meat alone, insome cases the patient having been on a meat-dietfor several days; under such circumstances I havefollowed the usual custom of calling it sarcolacticacid.

If after a test-meal consisting of albuminoids andstarches, lactic acid is found in the stomach-con-tents at the expiration of one hour or longer, itmay be called abnormal. I have found during thepast few years that lactic acid very frequently existsin large quantities in the stomach during the latehours of digestion, and that it is persistently presentin some cases, without regard to the character ofthe food or to the period of digestion. Indeed, Ihave cases on record in which lactic acid was pres-ent in excess during the whole period of gastricdigestion, and as many of these cases had dimin-ished peristalsis, their stomachs were free from lacticacid only a few hours during the twenty-four.

When hydrochloric acid exists in the stomach inproportions over from 0.2 to 0.4 of 1 per cent., wedignify the defect in gastric chemistry by the namehyperchlorhydria, or an excess of hydrochloric acid.

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But such a state is not more definite, nor is it moresusceptible of detection, study, and treatment, thanlactic-acid excess; nor are the etiologic factors moredefinite in the former than in the latter. I there-fore think it reasonable to recognize the conditionas an entity, and so consider it.

Lactic acid in abnormal quantity is found in thestomach in many cases having a deficiency ofhydrochloric acid. It is difficult to determine inthese cases whether the lactic-acid excess is thecause or the consequence of the diminished amountof hydrochloric acid. If, however, upon the with-drawal of all starches and milk-foods from the dietfree hydrochloric acid appears in normal amount, itis probable that the excess of lactic acid dependsupon improper diet rather than upon primarilydiminished secretion of hydrochloric acid. If, onthe other hand, free hydrochloric acid does notappear in the gastric contents after stopping starchyand milk foods, it is probable that its secretion isreally deficient and therefore lactic-acid fermenta-tion is rendered easy.

A very common cause of lactic-acid excess isfound in impaired motility of the stomach, whichallows too long retention of its contents, with theover-production of lactic acid by fermentation.With insufficient peristalsis poor absorption oftenexists, and it is in such conditions that I have fre-quently been able to demonstrate an excessive totalacidity of the gastric contents, owing to the pres-ence of both hydrochloric and lactic acids. Thusin gastrectasia of the Germain-See type, the stom-ach contains not only an excess of hydrochloric

4acid, but usually also an excess of lactic acid, andthe gastric mucous membrane is incessantly sub-jected to the action of highly irritating contents.When dilatation is associated with stenosis of thepylorus from a malignant growth, hydrochloric acidis present in small amounts only, or is entirelyabsent. In some of these cases I have found verylarge quantities of lactic acid, usually with otherorganic acids, making a total acidity far in excess,while other cases were characterized by a very smallamount of lactic acid and a faint total acidity.

Chronic catarrhal gastritis, resulting from what-ever cause or causes, renders lactic-acid excess liable.In cases of atrophy of the gastric glandules and aconsequent absence of gastric juice we would ex-pect to find lactic-acid fermentation at its height,but such is not the case. In four cases of thisnature that I reported 1 the gastric contents werealmost invariably neutral in reaction unless acidfoods had been taken. In other cases, as yet unre-ported, lactic acid was found in moderate amounts,and the total acidity was always subnormal.

Of all the factors entering into the productionof lactic-acid excess, none is so potent as improperdiet. The ingestion of mixed starchy milk pud-dings at the end of a hearty meal results in theformation of so much lactic acid that its fermenta-tion is perpetuated throughout the entire period ofdigestion, to the hindrance of proper change of thealbuminoids and starches. The common customof eating pastries, sweetmeats, ice-cream, cakes,

1 New York Medical Journal, May 27, 1893.

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and cheese after having eaten thick soups, meats,fish with various sauces, entrees made with cream,salads and salad-dressings, is to blame for manydigestive disorders.

Drinking milk at meals and between meals, ox-living on milk alone, not uncommonly lights upthe lactic-acid habit in the stomach, and cases ofthis habit illustrate the baneful effects of persistencein a diet that is not regulated by the condition ofthe gastric chemistry.

I cannot emphasize sufficiently the importance oflowered general health in the establishment of agastric state in which the over-production of lacticacid is made easy. When the blood is reduced andthe nervous and muscular systems are very muchenfeebled, the functions of the stomach are imper-fectly performed, because the organ is supplied byimpoverished blood, its innervation is disturbed,and its musculature is weak. Therefore under themany indiscretions in diet that are inevitable as theaverage individual lives and as the average cookingprevails, with all its death-dealing virulence, gastricchemistry is necessarily disturbed.