Effect of ascorbic acid on copper and cholesterol in adult cynomolgus monkeys fed a diet marginal in copper.

The effects of prolonged consumption of high levels of dietary ascorbic acid on copper metabolism and cholesterol in adult monkeys fed a diet low or marginal in copper were investigated. Small reductions in serum copper and in serum ceruloplasmin levels were observed when high levels of ascorbic acid were fed. During the period of copper depletion there was a gradual but significant (p less than 0.001) increase in serum cholesterol. The level of ascorbic acid supplementation had no effect during this phase. When copper was added back to the diet, serum cholesterol levels leveled off or declined in the monkeys receiving the low (1 mg/day/kg body weight) dose of ascorbic acid. Cholesterol levels continued to increase in the group receiving the higher ascorbic acid supplement (25 mg/day/kg body weight). These data suggest that high levels of ascorbic acid supplementation may make dietary copper relatively unavailable for regulating cholesterol metabolism.