this tag includes studies designed to assess the consequences of food or nutrient intake and utilization in the intact organism, including humans, and the metabolic and behavioral mechanisms involved; encompass investigation of nutrient variables at the cellular or subcellular level; includes research designed to elucidate the metabolic role or function of nutrients in both animal models and humans; includes studies concerned with genetic-nutrient-environmental interactions where a nutrient is a variable; includes dietary studies expected to produce significant changes in health status, including the maintenance of health and the treatment of disease; always index at the T level.