Approaches to risk assessment for macronutrients and amino acids

Risk assessment is a well-established framework for organizing and evaluating diverse, and sometimes conflicting information, to assess the likelihood that agents in the environment may harm human health under known or expected conditions of exposure. Risk assessments are used by regulatory and public health officials to guide judgments and actions regarding the need for risk reduction and the appropriate means to achieve it. These judgments and actions are called risk management, and are guided by law, historical precedent and public health, economic and social concerns. Those in the nutrition community who have been called upon to make recommendations regarding adequate nutrient intakes have long been engaged in the practice of risk assessment. That is, they have assessed the harmful health effects of inadequate intakes and defined intakes likely to avoid such harm. During the past decade attention has turned to the potential health risks of excessive nutrient and nutritional supplement intakes. A recent study released by a committee of the Institute of Medicine illustrates the difficulties in deriving risk-based upper levels of intake for nutrients and nutritional supplements. Amino acids were the subject of extensive discussions by this committee, but in no case was an upper level of intake recommended. It is clear that the extent of scientific investigation of the harmful effects of amino acids has been highly uneven, and that significant questions remain regarding the appropriate methodologies to study such effects.