Multivitamin, Breast Cancer Link SeenApr 2, 2010 | Parker Waichman LLP
The researchers pointed out that the study results do not prove that the supplements directly contribute to the disease. For example, it is possible that factors the study did not measure could explain the association between multivitamins and breast cancer. However, the researchers said the matter warrants further research.
The study authors recommend that until more is known about the possible association between multivitamins and breast cancer, women would be best served if they get vitamins and minerals from a well-balanced diet rather than pills.
The study involved 35,000 Swedish women aged 49 to 83. Just over a quarter said they took multivitamins. Overall, those women were 19 percent more likely to develop breast cancer. During about 10 years of follow-up, 974 women were diagnosed with breast cancer, and 293 of these diagnoses occurred among the 9,017 women who reported using multivitamins, WebMD said.
The women in the study did not provide information on what brands of vitamins they took. Other factors, like age, family history of breast cancer, weight, fruit and vegetable intake, and exercise, smoking and drinking habits, were taken into account.
According to a Reuters report, there are some plausible explanations for why multi-vitamin use would be associated with higher breast cancer rates. For example, other research has found that women who take multivitamins have increased breast density, which is linked to a relatively higher risk of breast cancer. However, Reuters said it is not clear if multivitamins actually cause the higher density.
Animal studies have also linked breast cancer to the B vitamin folic acid, Reuters said, though human studies have found varying results.