Calcium May Reduce Colon Cancer Risk in Men

Source: Tufts University
May 16, 2002 (Reviewed: April 19, 2004)

The search for a link between diet and risk for colon cancer has focused in recent years on the roles that specific nutrients, such as calcium, may play in colon health. More evidence of the cancer-fighting potential of this mineral was recently published in the Journal of the National Cancer Institute.

Looking for a connection

Harvard researchers pooled diet and lifestyle data on more than 100,000 men and women participating in two large US health studies. They were looking for a correlation between calcium intake - from both foods and dietary supplements - and the incidence of colon cancer over a 16-year period.

The women's calcium intake did not seem to have much of an effect on their risk of developing colon cancer. But it was a different story for the men, in whom intakes of at least 700 mg per day were associated with about a 40% lower risk of colon cancer. This effect was not, however, what scientists call a "dose-dependent response," meaning that intakes greater than 700 mg did not appear to afford any additional protection.

How it might work

Scientists think that calcium may inhibit the formation of colon cancer cells by binding with bile acids and fatty acids, both of which can trigger abnormal cell growth within the colon.

The exact association between calcium and colon cancer, however, is still unclear, with some studies, but not others, linking a high-calcium diet with reduced cancer risk.

It's possible that the effect may be due to other nutrients in calcium-rich foods. But in this current study, the use of calcium supplements was associated with a decreased risk, suggesting that it was the calcium itself - and not some other dietary factor - that produced the beneficial effect.

What you can do

The American Institute for Cancer Research points out that colon cancer - the fourth most common type of cancer worldwide - is affected by environmental factors, which means you may be able to reduce your risk through lifestyle changes. There is convincing evidence that regular exercise and a diet that includes plenty of vegetables are protective. Conversely, you may be putting yourself at higher risk if you smoke, are overweight, and consume a diet high in saturated fat and red meat.

Regular screening is also an important tool in lowering your risk of developing or dying from colon cancer, because screening may identify the disease when it's in its earliest and most treatable stages. Talk to your doctor and check the American Cancer Society website (see link below) for current guidelines on which tests are recommended for you.

Source

• Calcium intake and risk of colon cancer in women and men. K. Wu, W. Willett, C. Fuchs,  et al., J Natl Cancer Inst, 2002, vol. 94, pp. 437--446

Related Links
The American Cancer Society website
Another Look at Diet and Colon Cancer
The Cancer Survivors' Bill of Rights
Does Fiber Affect Colon Cancer Risk?
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