Canadian Cancer Society Recommends Vitamin D to Reduce Cancer Risk

After reviewing a growing body of evidence suggesting a strong link between Vitamin D and lowered risk for various cancers, the Canadian Cancer Society has announced the first ever Vitamin D supplement advisory as a cancer preventive measure.

Mounting Evidence on Vitamin D's role in cancer prevention

We are not surprised by the Canadian Cancer Society's recommendation. Indeed, mounting evidence has suggested daily intake of vitamin D should be raised from 400 IU to 1000 IU.

In December 2005, we reported a Vitamin D review study. Researchers from the University of California found that oral intake of 1000 IU vitamin D can reduce the risk of colon, breast, and ovarian cancers by as much as 50 percent. Since it is difficult to obtain 1000 IU of Vitamin D daily from food sources alone, the author recommended taking 1000 IU of the active form Vitamin D (D3 supplement) daily.

Another study published in the Journal of the National Cancer Institute in April 2006 conducted by the Harvard School of Public Health examined cancer incidence and Vitamin D exposure in over 47,000 men. Researchers found that a high level of Vitamin D (~1500 IU daily) was associated with a 17 percent reduction in all cancer incidences. The benefit of 1500 IU of Vitamin D was even greater in digestive cancers, with a 45 percent reduction of deaths from digestive cancers.

A recent study published in The American Journal of Clinical Nutrition in June 2007 found that taking Vitamin D supplements (1100 IU) and calcium substantially reduces risk of all cancers in post-menopausal women.

What about the Sun?

The Canadian Cancer Society does not recommends relying on the sun to obtain Vitamin D. In their press release, Heather Logan, Director, Cancer Control Policy of the Society said, "It's possible that just a few minutes of unprotected sun exposure every day could increase skin cancer risk for some people." Using sunscreen with SPF 15 or higher is recommended at all times.

The Bottom Line:

It is rather difficult to reach the recommended 1000 IU of Vitamin D solely through food. Therefore we recommend Vitamin D supplements, particularly D3 supplements. However, it is wise to start including more Vitamin D-rich foods in your diet. One glass of milk contains 100 IU of Vitamin D. Other food source includes fatty fish and egg yolks. Also look for Vitamin D fortified products such as yogurt and breakfast cereals.