The effect of caloric restriction on glycation and glycoxidation in skin collagen of nonhuman primates.

The accumulation of Maillard reaction products increases with age in long-lived proteins and can be retarded by caloric restriction. Here we determined whether caloric restriction inhibits formation of glycation and glycoxidation products in skin collagen of squirrel and rhesus monkeys between 1990-1997. Restricted monkeys (n = 11, n = 30, respectively) were maintained at 70% of caloric intake of controls (n = 25, n = 32, respectively). Glycation was assessed by furosine and glycoxidation by pentosidine and carboxymethyl-lysine. With age, the rate of furosine formation moderately but nonsignificantly (p >.05) increased in both control monkey groups. It significantly (p =.011) decreased in the caloric-restricted rhesus, but not squirrel monkeys. Caloric restriction did not significantly decrease the pentosidine or carboxymethyl-lysine rates in either species of monkeys. These results suggest that caloric restriction, when maintained long-term in nonhuman primates, tends to decrease glycation, but not glycoxidation.