Women who take a daily multivitamin pill may face a higher risk of breast cancer, a new study has claimed.
In the 10-year study, which followed more than 35,000 women, boffins found that those who regularly took a multi-vitamin pill increased the risk of developing a tumour by 19 per cent, reports News.com.au.
The study, conducted by Sweden's Karolinska Institute, has been published in the American Journal of Clinical Nutrition.
According to researchers, a "biologically plausible" explanation for the effect could be that taking vitamin and mineral supplements significantly increases the density of breast tissue, a strong risk factor for breast cancer. Folic acid, often present in a potent form in multi-vitamins, may also accelerate tumour growth.
"Results from this prospective study suggest that the use of multivitamins may increase the risk of breast cancer," the lead author of the study, Susanna Larrson, said.