Multivitamins may negatively affect breast cancer risk

April 1, 2010

Older women who take multivitamins may be increasing their risk of developing breast cancer, new research that demonstrates an association between the 2 suggests.

Older women who take multivitamins may be increasing their risk of developing breast cancer, new research demonstrating an association between the 2 suggests. The study was published in the online March 24 edition of American Journal of Clinical Nutrition.

The results are part of a 10-year study involving 35,000 women from Sweden (aged 49 to 83 years) who were free of cancer at study start. After approximately 10 years, 974 women went on to develop breast cancer.

Of the study participants, those women who took multivitamins at study start had a 19% greater chance of developing breast cancer compared with nonusers of multivitamins. This result emerged after accounting for factors such as age, family history of breast cancer, weight, fruit and vegetable consumption, and exercise, smoking, and drinking habits.

However, of the 9,017 women who took multivitamins, just 293 were diagnosed with breast cancer. Further, 681 women of the 26,000 women who did not use multivitamins also went on to develop breast cancer.Researchers note that although the study denotes a marginally greater risk of breast cancer among multivitamin users overall, the risk to individuals is minimal.

Based on the study findings, women are still advised to attain appropriate vitamins and minerals from a balanced diet rather than relying on pills.