The nutritive value of Brazilian soy products tested in malnourished children.

The nutritive value of a soya milk and soya protein isolate available in Brazil was tested in formulas fed to 30 malnourished children during a period of 25 days. The chemical composition of all formulas was similar, including their energy and protein content. The protein (1.5 g/100 ml) was supplied by either cow's milk, unfortified soy milk, unfortified soy protein isolate, and methionine-enriched soy milk or methionine-enriched soy isolate. Methionine was added at the level of 1.5 g/100 g of protein. The trials included clinical, biochemical and nitrogen balance studies, and results indicated that these soy products formulas did not have the same nutritive value of cow's milk. However, the nutritional quality of soy milk was improved by methionine supplementation, but the soy protein isolate was not affected by the addition of the same amino acid. Average nitrogen retention as percent of intake ranged from 31.8 to 34.7 in the children fed cow's milk. Those that received soy milk retained 10.5 to 15.3%, and when methionine was added the average retention increased from 17.2 to 24.8%. When the isolated soy protein was fed, the average retention values were 14.7 to 16.5% without methionine, and 11.0% when the methionine-supplemented formula was used. Factors that could influence the results and the importance of the subject are discussed.