Vitamin C in the control of hypercholesterolemia in man.

The activity of the cholesterol 7 alpha-hydroxylating system containing cyto-chrome P-450 is depressed in the liver of guinea-pigs with chronic marginal vitamin C deficiency. Slowing-down of this rate-limiting reaction of cholesterol transformation to bile acids causes cholesterol accumulation in the liver, blood plasma and arteries, increase in the index total: HDL cholesterol, prolongation of plasma cholesterol half-life, increase in the index cholesterol: bile acids in the gall-bladder bile, cholesterol gallstone formation and atheromatous changes on coronary arteries in guinea-pigs with long-lasting marginal vitamin C deficiency. The most effective means for preventing these changes are vitamin C doses ensuring maximal steady-state levels of ascorbate in the tissues. In most of hypercholesterolemic persons with a low vitamin C status, the administration of ascorbic acid in doses 500-1000 mg per day lowers total cholesterol concentration in blood plasma. This effect may be reinforced through a simultaneous administration of bile acids sequestrants, such as cholestyramine or pectin. In every form of hypercholesterolemia therapy (dietary and/or pharmacological), an adequate vitamin C supply should be ensured in doses capable of creating maximal steady-state levels of ascorbate in human tissues.