Soybean protein in human nutrition: An overview

Abstract The nutritional value of processed soy protein in human protein nutrition is reviewed on the basis of growth, nitrogen balance and metabolic studies in infants, children, adolescents and adults. When well processed soy products serve as the major or sole source of the protein intake, their protein value approaches or equals that of foods of animal origin, and they are fully capable of meeting the long term essential amino acid and protein needs of children and adults. The significance of the sulfur amino acid content of soy protein for practical human nutrition is also examined. For young children and adults, under conditions of normal usage of soy protein, it is concluded that methionine supplementation of good quality products is unnecessary and possibly undesirable. For feeding of the newborn, the limited data available suggest that supplementation of soy‐based formulas with methionine may be beneficial. However, the appropriate level of supplementation is considerably less than that suggested from results obtained in rat feeding studies. At total protein intakes that approximate current dietary protein allowances, well processed soy protein products can replace meat and fish proteins without reducing the utilization of dietary nitrogen in adults, and they can serve as nutritionally valuable protein sources in cereal‐based diets for child feeding. The value of long term studies concerned with tolerance to and acceptability of new soy protein products in adults is emphasized, and favorable results with two isolated soy protein products are described. The data indicate that properly processed soy protein foods are well tolerated and of good protein value for humans of all ages.