Protein and amino acid requirements in the elderly

Estimates of protein and amino acid requirements in this paper are proposed for healthy elderly people. The estimate of protein requirement was based on nitrogen (N) balance, as well as functional indicators such as immune function or muscle strength. Data suggest that the protein requirement for nitrogen equilibrium in the elderly, is greater than 0.8 gm/kg body weight/day. There do not appear to be any adverse consequences with protein intakes that are about 1 gm/kg body weight/day. The tentative recommendation in this paper is higher than the current mean recommended intake of protein (FAO/WHO/UNU, 1985). However, because of methodological difficulties, the data does not allow for a confident prediction of what the exact level of protein intake should be. Further studies are needed to come to a firm conclusion on the exact protein requirement. Indispensable amino acid requirements based on nitrogen balance data, in the elderly, are fragmentary and conflicting. These requirements can alternatively be based on obligatory nitrogen loss, for which data is available in the elderly. The overlap of the obligatory nitrogen loss between the young and the elderly, suggest that the amino acid requirement based on this technique is similar in young and elderly individuals. Tracer based techniques measuring amino acid balance at different amino acid intakes, also support the view that there are no differences in the amino acid requirements between young and elderly people. In general, these amino acid requirement studies have been performed in healthy USA subjects, and data is needed to know if these estimates can be extended to populations from other, less-developed countries.