helpful and should be mandatory when nonspecific failure to thrive with unexplained deterioration in nutritional status is evident.7
An assessment of dietary intake is another useful but often neglected tool for determining the nutritional status of the aging. Dietary status indices provide information that helps a clinician make the differential diagnosis between primary malnutrition owing to inadequate dietary intake and malnutrition resulting from other causes. They can also offer some estimate of the patient's habitual diet, foodways, and abilities to purchase, prepare, serve, and clean up after meals, as well as any special restrictions or food prohibitions. Once these data have been collected, dietary intake is then assessed against some standard for nutrition, which, in the United States, is most commonly the Recommended Dietary Allowances (RDAs). The RDAs are commonly agreed upon standards for planning and assessing nutrient intake at various ages that are published periodically by the National Research Council. At present, there are no separate recommendations for those over 55 years of age for most nutrients, owing to the absence of evidence on nutrient requirements among older individuals; however, there is some information on useful alterations in nutrient recommendations for older individuals, and these data have recently been summarized.106 The most striking alteration in nutrient requirements for those over the age of 50 is the reduction in energy needs, which decreases by 6 percent from ages 51 to 75 and another 6 percent after 74 years of age. There are strong data to support the recommendations for decreased energy needs;13,83,95,113 what is not so clear is whether the decreases in lean body mass that account for much of this decrease are inevitable with advancing age or simply an artifact of inactivity. Exercise programs and more physically active lives among those over 50 might preserve lean body mass and thereby increase resting metabolic rates (and consequent energy needs). Increasing physical activity also increases energy expenditures in discretionary physical activity, further increasing energy outputs.
Additional standards have been developed by a large number of expert bodies, including the National Research Council (NRC) for other substances in food such as cholesterol or dietary fiber that are not dealt with in the RDAs. One NRC committee recently published an authoritative report on diet and health that makes recommendations regarding a number of dietary constituents for which the RDAs