Protein, an essential component of diet, is required for both total amino nitrogen and indispensable amino acids to synthesize body protein and other nitrogen-containing compounds such as peptide hormones and neurotransmitters. Adequacy of dietary protein and amino acids is especially critical in sole-source foods such as infant formulas and enteral foods for the elderly. The role of dietary protein and its interactions with dietary fat and vitamins in reducing many chronic diseases such as cardiovascular disease, hypertension, osteoporosis and certain types of cancer are receiving greater attention. To ensure safety and adequacy of dietary proteins and amino acids, new protein products/fractions (produced through biotechnology or by processing) from animal and/or vegetable sources and associated minor bioactive compounds have to be studied . These include naturally occurring bioactive factors such as phytoestrogens (with potential hormonal effects) in soybean or those formed during processing of proteins such as lysinoalanine (LAL, an unusual potentially toxic amino acid derivative). To address these issues, research studies concerning analysis of proteins in food and determination of their biological effects (safety, nutritional quality and health) and requirements are underway in the Bureau of the Nutritional Sciences of the Food Directorate. These studies are conducted to support Canadian government policy development, standard setting and risk assessment with respect to safety and nutritional quality of dietary proteins and health.