Women who take large amounts of folate, vitamin B2, B6 or B12 supplements may be increasing their risk of uterine cancer, according to research presented at the 16th International Meeting of the European Society of Gynaecological Oncology (ESGO) in Belgrade, Serbia, 11-14 October 2009.

Results from a 20 year follow up of dietary intake in over 23,000 postmenopausal women taking part in the Iowa Women’s Health Study, have shown that women who consumed large amounts of the supplements were twice as likely to get type II uterine cancer than women who had normal intakes, although there was no effect on type I uterine cancer.

Dr S Uccella, from the department of gynaecologic surgery at the Mayo Clinic, Rochester, USA., explained that the results contrasted with the expected protective effects of the supplements and further investigation showed that, while a folate intake of 200-600mcg/day did have a protective effect, taking higher levels nearer 1000mcg/day increased the risk of uterine cancer.

He concluded that the research could have implications for women’s health in countries such as the USA and Canada, where folate and B vitamins are added to foodstuffs, and other countries considering similar action.