Apart from increasing bone mineral density, decreasing bone loss, and reducing osteoporosis risk, calcium also confers protection against colorectal cancers, reduces cardiovascular disease risk, and improves management of body weight (Office of Dietary Supplements, 2016).
Epidemiological studies have shown that in individuals consuming 700 to 1200 milligrams of calcium per day, colon cancer risk was reduced by 31 to 45 percent as compared to those with lower daily calcium intake. Randomized clinical experiments have also demonstrated that in subjects taking 1200 to 2000 milligrams of elemental calcium per day, the risk of adenomas, which are precursors of colorectal tumors, was significantly lower as compared to that in the placebo group. It is suggested that calcium may bind to fatty and bile acids in the GI tract to reduce their adverse effects on the colorectal lining and promote cell multiplication. Calcium may also induce differentiation of colon cells, kill cancer-causing cells, and enhance cell signaling, all of which prevent tumor formation (National Cancer Institute, 2009).
The Iowa Women’s Health Study has shown that calcium decreases mortality due to ischemic heart disease as has been observed in postmenopausal women, and stroke, although a cohort study in older women from Sweden reports the opposite. It is hypothesized that calcium confers cardioprotective effects by reducing intestinal lipid absorption, boosting excretion of lipids, increasing movement of calcium within cells, and by reducing serum cholesterol levels (Office of Dietary Supplements, 2016).
Calcium is thought to help in weight management both when a diet rich in calories is consumed excessively and when calorie consumption is restricted. When calorie-rich diets are consumed, calcium attenuates weight gain by reducing lipid accumulation in the adipocytes (Zemel, 2004). It is proposed that calcium confers this effect by reducing the production of parathyroid hormone and vitamin D (Office of Dietary Supplements, 2016). When calorie consumption is restricted, calcium maintains thermogenesis and boosts lipolysis to hasten the loss of body weight (Zemel, 2004).
Higher dietary calcium, particularly that obtained from dairy sources prevents lipogenesis, binds to the fat obtained from food to decrease intestinal lipid absorption (Office of Dietary Supplements, 2016), and enhances lipid oxidation as has been shown in mice. Epidemiological studies observe that in obese individuals consuming more than 3 servings of milk-based products daily there is a decrease in the mass of the adipose tissue as compared to individuals consuming lesser amount of such products (Zemel, 2004), leading to a decrease in the body weight.
References
Office of Dietary Supplements (2016, Feb. 11) Calcium: Fact sheet for health professions. Retrieved from https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/
National Cancer Institute (2009, May 4) Calcium and cancer prevention: Strengths and limits of evidence. Retrieved from http://www.cancer.gov/about-cancer/causes-prevention/risk/diet/calcium-fact-sheet
Zemel, M.B. (2004) Role of calcium and dairy products in energy partitioning and weight management. American Journal of Clinical Nutrition, 79 (5): 9075- 9125. http://ajcn.nutrition.org/content/79/5/907S.full
.
