Effect of calcium level and source on plasma total and lipoprotein cholesterol in men under controlled dietary conditions

A metabolic study was conducted with 23 men to determine the effects on plasma lipids and lipoproteins of a high calcium intake from two sources compared to a normal level of calcium intake over an eight week controlled feeding period. Three diet treatments were examined: 1) high dietary calcium mainly from dairy sources (1600-1800 mg/day), 2) high dietary calcium supplied by a CaCO₃ supplement (1600-1800 mg/day), and 3) normal dietary calcium intake from mixed sources (600-800 mg/day). Fat, carbohydrate and protein were provided in the ratio of percent kcal as 40:49:11. Nutrient, cholesterol levels (500 mg) and polyunsaturated to saturated (P/S) fatty acid ratio (0.446) were held constant for all diet treatments. There were no significant differences between treatments or across time in plasma TC, LDL, HDL or VLDL-cholesterol. Levels remained similar throughout the controlled diet treatment and the pre- and post-treatment periods. At the level of fat content and P/S ratio tested, there was no hypocholesterolemic effect of elevated calcium intake on plasma lipids.