The Biological Value of Corn and Wheat Proteins in the Male Infant, with a Note on the Utilization of D-Tryptophan

Abstract

It has been found that the nitrogen retention and weight gain of infants maintained on a synthetic diet in which tryptophan- and lysine-supplemented commercial zein constituted the principal source of nitrogen were inferior, by reason of the poor digestibility of the zein, to those obtained on a casein diet fed at the same fluid, caloric distribution and nitrogen levels. A diet in which tryptophan- and lysine-reinforced corn gluten provided the major source of protein also proved to be nutritionally inadequate for the infant. In contrast, a lysine-enriched wheat gluten diet supported a nutritional state in the infant comparable to that afforded by an evaporated milk formula. Evidence, albeit inconclusive, is presented which suggests that the inclusion of D-tryptophan in the diet may have an untoward nutritional effect.