Multivitamin Overuse Linked to Aggressive Prostate Cancer
Large-scale study finds increased risk with excessive use of multivitamins and antioxidants
WEDNESDAY, May 16 (HealthDay News) -- Men who take excessive amounts of multivitamins may have an increased risk of advanced and fatal prostate cancer, according to the results of a study published in the May 16 issue of the Journal of the National Cancer Institute.
Karla Lawson, Ph.D., of the National Cancer Institute in Bethesda, Md., and colleagues studied 295,344 men who were initially free of prostate cancer. After five years, 10,241 men were diagnosed with prostate cancer, 8,765 of whom had localized cancers and 1,476 of whom had advanced cancers.
The researchers found that men who took more than seven multivitamins per week had an increased risk of advanced and fatal prostate cancers compared to never users (relative risks 1.32 and 1.98, respectively). They also found an especially strong association between excessive multivitamin use in men who either had a family history of prostate cancer or who took individual micronutrient supplements such as beta-carotene, selenium or zinc.
"Results of ongoing clinical trials and further studies will be required to extend our knowledge of the impact of antioxidant supplements on health," state the authors of an accompanying editorial. "Is oxidative stress the cause of disease or rather a consequence? Is it wise to artificially modulate the delicate balance between oxidative stress and antioxidants in our cells? Ideally, we should have more data to address these questions."