Nutrition Study Design Questioned

Abstract

In Reply.— We welcome the interest in our study1 and are pleased to have the opportunity to respond to Dr Wilson's letter. At the initiation of our study, there were two equivocal reports on indices of protein metabolism in full-term infants fed human milk, whey-predominant formula, or cow's milk formula.2-4 Therefore, our objective was to assess whether specific parameters of protein metabolism responded quantitatively to dietary intakes of protein, nitrogen, and amino acids. Our results did confirm that plasma aminograms are elevated with feeding either a whey-predominant or a cow's milk formula3; however, we are the first to report that total protein (total nitrogen) intake is as important as protein quality in determining plasma amino acid response in infants.