Is gastric secretion or digestion impaired by a mixture of carbohydrate and protein in the diet?

Summary and Conclusions

Five people, free of any organic gastro-intestinal disease, were studied by repeated fractional gastric analysis following meals of distilled water, a pure carbohydrate, a pure protein, and mixtures of the two. Four had a normal gastric acid response and one was an achlorhydric. The studies were done in order to test the validity of the claims made that mixtures of protein and carbohydrate interfere with proper gastric digestion. The gastric secretory studies included the usual titration of acidity to Topfer’s and to phenolphthalein, hydrogen ion determinations, total chlorides, and quantitative pepsin. Gastric digestion was followed by quantitative determinations of reducing substances and amino-nitrogen in the separate fractions. More than 6,000 determinations were made on over 900 fractional specimens in the course of the studies. The results showed that:

(1) Mixtures of carbohydrate and protein in the test meal do not, in any way, interfere with gastric secretion.

(2) Not only do these mixtures not interfere with gastric digestion,but that carbohydrate digestion in the stomach is prolonged and encouraged by its mixture with protein. This is probably brought about by the more favorable reaction for continued ptyalin activity in the stomach as a result of the acid combining power of the protein. The same would be true following any regurgitation of pancreatic amylase from the duodenum.