Determination of First Limiting Nitrogenous Factor in Corn Protein for Nitrogen Retention in Human Adults

Abstract

Nitrogen retention of adult men fed isocaloric diets was significantly greater when white corn meal provided 8.0 g nitrogen/subject/day than when either 4.0 or 6.0 g nitrogen were supplied from corn protein. When a suboptimal intake of corn meal was fed (6.0 g nitrogen/subject/day), the optimal nitrogen retention level was re-established by the addition of 2.0 g nitrogen from any of several purified essential amino acids or other purified sources of nitrogen, or from both. Therefore, “nonspecific” nitrogen, that is, nitrogen from any metabolically usable, non-toxic source, is the first limiting nitrogenous factor in corn protein for nitrogen retention in adult men.