Modest increases in calcium intake reduce the risk of colon cancer, which is a malignant growth of cells in the large intestine. In a study, nurses and health professionals in the US, researchers from the Harvard School of Public Health have reported that among people with low-calcium diets, even a modest increase in calcium appeared to offer some protection against cancer. They studied two groups of nearly 88,000 registered nurses and about 47,300 male health professionals in the US that included dentists, pharmacists and veterinarians. Dairy products accounted for most of the calcium in their diets, according to food questionnaires that began in the 1980s and were updated through the 1990s.
Men and women who included more than 700 milligrams to 800 milligrams of calcium in their diets each day had a 40 per cent to 50 percent lower risk of distal, or left-side colon cancer, compared with participants taking less than 500 milligrams of calcium each day. Calcium may slow down epithelial cell growth, a process that can lead to cancer.
The researchers, however, cautioned that there may be a limit to the benefits of calcium. Taking more than 700 milligrams of calcium per day was not associated with any further protection against colon cancer.
Journal of the National Cancer Institute March 2002, Vol. 155(6)