CHAPTER 31:Interaction of Dietary Calcium with Genes of Transporters, Receptors and Enzymes Involved in Cholesterol Metabolism

Dietary calcium has been shown to decrease plasma total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol, particularly in postmenopausal women who have regularly taken calcium supplement for prevention of osteoporosis. Two possible mechanisms are associated with cholesterol-lowering activity of calcium supplement. First, calcium increases the bile-acid excretion due to its binding interaction with bile acids in the intestine. This is companied by upregulation of cholesterol-7α-hydroxylase (CYP7A1), a key enzyme in converting cholesterol to bile acids in the liver. Secondly, calcium supplement increases the cholesterol excretion, possibly mediated by downregulation of intestinal Niemann-Pick C1 like 1 (NPC1L1) and acyl coenzyme A: cholesterol acyltransferase 2 (ACAT-2), both of which are responsible for cholesterol absorption.