A new study reveals that a higher intake of calcium may reduce the overall risk of cancer for women and also reduce the risk of colorectal cancer and other digestive cancers for both men and women. The study appears in the February 23 edition of Archives of Internal Medicine.

Researchers from the National Cancer Institute (NCI) analyzed data from nearly 500,000 people who participated in the National Institutes of Health-AARP Diet and Health Study that began in 1995. Participants between the ages of 50 and 71 filled out a questionnaire reporting how often and in what quantities they consumed dairy products and a wide variety of other foods, and whether they took supplements. Their records were then linked with state cancer registries to identify new cases of cancer.

After an average of seven years of follow up, nearly 50,000 cases of cancer had occurred. Calcium intake was associated with a decrease in the overall risk for all cancers in women and the more calcium women got, the more the risk decreased. Beyond 1,300 milligrams of calcium per day, no further reduction occurred.

While men did not display the same overall reduction in cancer risk, calcium intake was associated with reduced risk of cancers of the digestive system for both men and women. The top 20 percent of men who consumed the most calcium through food and supplements (about 1,530 milligrams per day on average) had a 16 percent lower risk of digestive cancers than the bottom 20 percent who consumed the least calcium (526 milligrams per day).

For women, those in the top 20 percent of calcium consumption (1,881 milligrams per day) had a 23 percent lower risk of these cancers than those in the bottom 20 percent (494 milligrams per day). This risk reduction was particularly pronounced for colorectal cancer. The study found no relationship between calcium and prostate cancer, breast cancer or other cancers.

The researchers believe that calcium may help prevent digestive system cancers by reducing abnormal growth in cells in the gastrointestinal tract or by reducing damage to the mucous membrane in the large intestine.

Calcium has long been known to be associated with bone health and calcium intake is critical in preventing osteoporosis. However, previous research into the role of calcium in cancer prevention has produced mixed results. The present study is one of the largest ever undertaken, but it relied on interviews instead of blood tests and can therefore only estimate the amount of calcium each participant had consumed.

Does this mean you should run out and buy calcium supplements? Perhaps, but the researchers found that the benefits of calcium were mostly associated with calcium-rich foods rather than supplements, although calcium from supplements alone was still effective in reducing colon cancer risk in men. Foods with lots of calcium include dairy products such as milk and yogurt and leafy green vegetables. The recommended daily calcium intake for older people is 1,200 milligrams, while for younger adults it is 1,000mg. Adolescents should get 1,300 milligrams per day of calcium.

For more information about nutrition or dietary supplements, join the Healia Health Community for Diet and Nutrition or the Healia Health Community for Dietary Supplements. Find out more about colorectal cacner at the Healia Health Community for Colorectal Cancer.

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