EFFECTS OF DIETARY CALCIUM ON CONCENTRATIONS OF LIPIDS, GLUCOSE an‎d INSULIN IN MALE SPRAGUE-DAWELY RATS

INTRODUCTION: A number of experimental studies have shown that dietary calcium may help improve hypercholesterolemia induced by high-cholesterol/high-fat diets through saponifying cholesterol/fat in the intestine. There is little evidence showing the effect of calcium in a low-fat, low-cholesterol diet on the lipid profile. We evaluated the effect of different levels of dietary calcium, in a cholesterol-free/low-fat diet on serum cholesterol, triglyceride, glucose and insulin, as well as fecal excretion of lipids. METHODS: Forty-eight male Sprague-Dawely rats were randomly divided to receive three levels of dietary calcium (0.2, 0.5 and 1.2 % W/W) for 10 weeks. Finally, the rats were decapitated and their truncal blood was sampled for biochemical analysis. Fecal fat excretion, total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, glucose, and serum insulin were measured. Low-density lipoprotein (LDL) cholesterol was calculated using the Friedwald equation. RESULTS: Serum cholesterol and LDL cholesterol of rats receiving a high-calcium diet were significantly lower than those of the other two groups (P<0.05), but serum triglycerides, HDL cholesterol, glucose and insulin and fecal fat excretion were not statistically different in the three groups (P>0.05). CONCLUSIONS: Our findings suggest that, even with a low-fat low-cholesterol diet, calcium has hypocholesterolemic effects, i.e. there may be hypocholesterolemic mechanisms, other than intestinal saponification of cholesterol and/or fatty acids, including endogenous mechanisms for dietary calcium.