Vitamin B Complex Studies with Diets Differing in the Level of Protein

Abstract

Summary

Experiments involving the feeding to rats of diets varying in the level of casein were carried out. The following facts were established:

1. In ad libitum feeding the fecal elimination of the B vitamins studied closely paralleled the level of dietary protein. In equalized feeding the fecal elimination of biotin, pantothenic acid, and nicotinic acid was directly proportional to the protein content of the diet.

2. The hepatic storage of the B vitamins studied was correlated directly with the protein content of the diet. This relationship existed both in ad libitum and controlled feeding experiments, The hepatic stores of folic acid, biotin, pantothenic acid, and riboflavin found in rats fed the lower levels of protein were indicative of either frank or incipient deficiencies.

3. Leucopenia and agranulocytosis were induced readily by diets low in protein. Under these conditions the existence of the dyscrasia was correlated with the reduced fecal elimination and hepatic storage of folic acid. When diets more nearly optimal with respect to casein level, but in greatly restricted amounts, were fed, leucopenia and agranulocytosis were encountered despite the existence in many of the animals of adequate stores of folic acid. Reasons were presented for attributing the condition to the ingestion of insufficient protein and, more specifically, of certain essential amino acids.

4. Low hematocrits, hemoglobin values, and red cell counts were observed occasionally in rats ingesting low protein diets or highly purified diets containing succinyl-sulfathiazole (SST).