Dietary carbohydrate decreases 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and cholesterol synthesis in rat liver.

Diets high in carbohydrate and low in fat led to a decrease in the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase in livers of healthy, reverse light-cycled rats. The effect on reductase was due both to a decline in expressed enzyme activity and to a decrease in total number of enzyme molecules. Inhibition of reductase activity was paralleled by a fall in hepatic cholesterolgenesis and by an increase in triglyceride formation. Thus, a reduction in endogenous cholesterol synthesis may explain the serum cholesterol-lowering effect of high carbohydrate, low fat diets in man.