All dietary cholesterol is derived from animal products. The major sources of cholesterol in the diet are egg yolks, products containing milk fat, animal fats, and animal meats. Many studies have shown that high intakes of cholesterol will increase the serum cholesterol concentration. Most of this increase occurs in the LDL cholesterol fraction. When cholesterol is ingested, it is incorporated into chylomicrons and makes its way to the liver with chylomicron remnants. There it raises hepatic cholesterol content and suppresses LDL receptor expression. The result is a rise in serum LDL cholesterol concentrations. Excess cholesterol entering the liver is removed from the liver either by direct secretion into bile or by conversion into bile acids; also, dietary cholesterol suppresses hepatic cholesterol synthesis. There is considerable variability in each of these steps in hepatic cholesterol metabolism; for this reason the quantitative effects of dietary cholesterol on serum LDL cholesterol levels vary from one person to another. For every 200 mg of cholesterol per day in the diet, serum LDL cholesterol is increased on average by about 6mgdl-1 (0.155 mmoll-1).
Was this article helpful?