Digestibility and Nutritional Value of Cereal Proteins in the Human Subject

Publisher Website
Google Scholar
Abstract
The apparent and ‘true’ digestibility in the human alimentary tract of the proteins of three cereal breakfast foods have been studied, namely, a wheat endosperm product, a so-called ‘whole wheat,’ and a precooked rolled oats. The nutritive value of the proteins was studied by a milk replacement method. This consisted of feeding the cereals in alternate periods with milk, providing 80% of the nitrogen, while 10% in both diets was supplied by cream and 10% by fruit. Alimentary or ‘metabolic’ nitrogen of the feces was determined in an unreported study and was found to be roughly proportional to body weight, total calories being also in that proportion. Apparent and ‘true’ digestibility of the different cereals parallelled each other, and for the most part the digestibility, whether apparent or true, was in the same order for the different subjects. The results confirm those of previous investigators in finding the apparent digestibility of endosperm products distinctly higher than that of whole grain products. ‘True’ digestibility, which undertakes to apportion fecal nitrogen correctly to food residues and alimentary products, gives obviously a higher ranking to all, but does not change notably the relative ranking of the products used. The milk-replacement value of the proteins of the precooked rolled oats and the ‘whole wheat’ were substantially the same numerically as their biological values. That of wheat endosperm was somewhat higher than its biological value. The replacement value method offers distinct advantages for experiments on human subjects because at all times the diet is tolerable and gives separable stools.