The Recommended Dietary Allowances (RDAs) are a set of nutrient and energy standards developed by the Food and Nutrition Board of the National Academy of Sciences. Periodically, a group of nutritional experts meet to review the latest science to help develop nutritional allowances for maintenance of good health. RDAs are defined as the levels of intake of essential nutrients judged to be adequate to meet the known nutrient needs of healthy persons. However, RDAs are not designed to determine optimal intake, and they do not consider the health benefits of non-essential nutrients.