Calcium is an essential and the most abundant mineral in the body. It is a major constituent of bone and teeth and crucial for muscle contraction, nerve conduction, beating of the heart, blood coagulation and maintenance of immune function. Vitamin D helps calcium absorption from the small intestine. Deficiency may cause osteoporosis. Rich sources are milk products, vegetable greens, tofu, and sardines (bones included). Adequate intake for adults is 1000-1200 milligrams/day. (For more detailed information, please visit ISM’s searchable database: Nutraceutical Search.)
Increased intake of dairy products may reduce the risk of developing breast cancer by at least 45 per cent. Amongst pre-menopausal women the benefits of dairy consumption were calculated to be even greater, with highest average dairy intake associated with a 65 per cent reduction in breast cancer risk. [Kesse-Guyot, E et al. Dairy products, calcium and the risk of breast cancer: Results of the French SU.VI.MAX Prospective Study. Annals of Nutrition and Metabolism, 51, 139-45.]
Dietary calcium and/or some other components in dairy products may modestly reduce risk of postmenopausal breast cancer. [Cancer Epidemiol Biomarkers Prev. 2005 Dec; 14(12): 2898-904.]
Women (n= 73,314: average age 55.5) who had the highest daily calcium intake had a 40% reduced risk of cancer of the colon or rectum than women with the lowest daily intake. The potential mechanism was not evaluated in this study, but the researchers note that previous research has linked calcium to a range of cancer inhibiting effects, including binding to carcinogenic bile acids, and promoting the differentiation and stopping the growth of cells in the colon. [International Journal of Cancer 2006 Vol. 119, pp. 2938-2942]
Women who have the most calcium in their diet had 25-45% less risk of colon cancer. [Cancer Epidemiology, Biomarkers & Prevention 2005]
People with colon polyps removed and given 1,200mg of Ca/day had 14% less risk of developing new colon polyps. [Journal of the National Cancer Institute 2003]
High risk colon patients have high rate of cell division in colons. After taking Ca for 2-3 months, the rate of cell division returned to normal. [Manolagus, Anticancer Research (1987) 7:625-38]
Low calcium intake increases risk of colon cancer. [Sorenson, (1988) Nutr. Cancer, vol 11 p 135]
Most population studies suggest that high intake of dietary or supplemental calcium seems to reduce the risk of adenoma recurrence and colorectal cancer. [Baron, Calcium Polyp Prev Study Group. N Engl J Med (1999) ;340:101-7]
High intake of dietary or supplemental calcium reduces the risk of adenoma recurrence and colorectal cancer. [Weingarten, Cochrane Database Syst Rev (2004);(1)]
Increased intakes of calcium from the diet and supplements may reduce the risk of colorectal cancer by up to 23 per cent in women. The highest average intakes of calcium (1,881 mg/d) were associated with a 23 per cent lower risk of such cancers, compared to women with the lowest average intakes (494 mg/d). [Park, Y, Leitzmann, MF, Subar, AF, Hollenbeck, A, & Schatzkin, A (2009). Dairy food, calcium, and risk of cancer in the NIH-AARP Diet and Health Study. Arch Intern Med, 169(4), 391-401.]
The potential protective effects of calcium supplements against colorectal cancer may carry on for five years after people stop taking the supplements. [Grau, MV et al Prolonged effect of calcium supplementation on risk of colorectal adenomas in a randomized trial. Journal of the National Cancer Institute, 99, 129-36.]
Calcium can reduce the risk of kidney cancer in women. [Cancer Causes and Control 2003]
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