The Effect of a Meal upon the Titratable Alkalinity of Blood.

Abstract

The effect of a meal upon the titratable alkalinity of the blood was studied in 47 subjects by the method of Sumner and Hubbard. 1 Specimen's were obtained after a night's fast and two hours after a meal by which the carbohydate tolerance was tested. 2 The meal consists of 100 gm. carbohydrate, 24 gm. protein, and 25 gm. of fat, fed as oatmeal, milk, sugar, dates, bread, butter, orange, and an egg. The subjects were patients in the sanitarium, in whom it was thought that some abnormality of carbohydrate metabolism might be present. The average blood sugar content, determined by Benedict's copper method, 3 was 93 mg. per 100 cc. before, and 115 mg. after the meal was fed. Of the cases studied 14 showed increases in blood sugar after the meal, greater than 25 mg. per 100 cc.; 5 of these were greater than 100 mg. per 100 cc.

The average values obtained before the meal were 44.7 cc. N/10 alkali per 100 cc. of blood when methyl red was used as an indicator, and 28.4 cc. when thymolphthalein was used. After the meal these values were 46.0 and 30.9 respectively. The distribution of the increases and decreases by the two methods is given in the table. In 6 cases the variation in the titration values by the two methods were of opposite sign, but in 4 of these, one of the methods showed variations of 1.0 cc. N/10 alkali or less. There were 2 cases in which no variation in one titration value was accompanied by a more or less significant variation in the other one. In the remaining 39 cases both titrations showed differences which were parallel.

It is evident from the average values and from the table that the majority of the cases showed an increased amount of titratable alkali after the meal with both indicators, but that the average difference was slight.