Questions surrounding multivitamin use

A study recently appeared online in the American Journal of Clinical Nutrition that raised some eyebrows. The Swedish study followed approximately 35,000 women (aged 49 to 83 when the study began in 1997). After 10 years, women who reported using multivitamins were 19 percent more likely to develop breast cancer than women who did not take multivitamins. The study authors controlled for factors like alcohol use, body weight, family history, smoking and others.

Questions linger

This is only the latest study to show that the role of supplements in cancer risk is anything but clear-cut.

Although researchers like to study the effect of promising nutrients in isolation, it’s unclear whether a given vitamin or mineral behaves the same way when it’s consumed as a supplement as when it’s consumed in a whole food.

Because of such complexities and lingering questions, the American Institute for Cancer Research (AICR) recommends looking to the whole diet to get the vitamins, minerals and phytochemicals that potentially help protect against cancer.

In fact, our expert report specifically recommends against relying on dietary supplements to protect against cancer.

The bottom line

This one new study is not, in itself, a reason to throw out your one-a-day vitamin. But it is a reason to redouble your efforts to eat a varied and healthful diet full of vegetables, fruits, whole grains and beans and low in red meat. That’s the overall pattern of eating that has been consistently associated with lower risk for cancer.

Some individuals who have nutrient deficiencies could benefit from a daily multivitamin. That’s why it’s vital to discuss all supplements you take – including a seemingly innocuous one-a-day multivitamin – with your doctor.

(Source: American Institute for Cancer Research: April 2010)