METABOLIC EFFECTS OF ARGININE IN A HEALTHY ELDERLY POPULATION

Recently there has been much interest in the use of arginine to stimul ate immune responses and to promote wound healing. In the present stud y, the effect of an oral supplementation with arginine on the metaboli sm of 45 healthy, nonsmoking, elderly volunteers was investigated. Sub jects were divided into two groups that received either arginine aspar tate (17 g free arginine) (n = 30) or a placebo (n = 15). The suppleme nts were taken for a period of 14 days. Dietary intake of food was not controlled. Blood chemistry, lipid profiles, and as an index of nutri tional status, serum insulin-like growth factor-1 levels and nitrogen balance were compared before and after supplementation. Two weeks of a rginine supplementation led to a significant elevation of serum insuli n-like growth factor concentrations and an improved and positive nitro gen balance (2.0 +/- 0.41 g N) when compared with controls (0.11 +/- 0 .47 g N; p = 0.0114). In addition the arginine-supplemented group demo nstrated a decreased total serum cholesterol with a reduction in the l ow-density lipoprotein but not the high-density lipoprotein fraction r esulting in a increase in the ratio of low- to high-density lipoprotei n fraction. No adverse effects were observed at this dosage of arginin e. The data suggest that oral arginine supplementation may be used saf ely in elderly humans.