American Journal of Clinical Nutrition, Vol 10, 142-152, Copyright © 1962 by The American Society for Clinical Nutrition, Inc.

The Nutritive Value of Maize Protein for Man

¹ From the Department of Medicine, University of Cape Town, Cape Town, South Africa

The biologic value of whole maize was measured in four Bantu adults with mental or static physical disabilities under carefully controlled conditions. In one of them the complete, classic method was used and endogenous and metabolic nitrogen were determined on a protein- (and fiber-) free diet. The biologic value was found to be 45 at 9 per cent and 57 at 5 per cent of dietary calories from protein. In the other three subjects, endogenous and metabolic nitrogen were estimated respectively from the surface area and dry weight of the diet. Similar values were obtained. At the higher intake level all the subjects were in positive nitrogen balance, so that the optimal biologic value of maize is probably nearer 57 than 45.

The digestibility of maize protein appeared to vary inversely with the intake. When referred against metabolic fecal nitrogen on a fiber-free diet the true digestibility was 82 per cent at an intake of 1 gm. protein per kg. and 91 per cent at 0.5 gm. protein per kg.

Although, as we have shown, the nutritive value of maize protein for man is not high, in subjects accustomed to eating large amounts of maize it does not appear to be as low as has been thought.