www.healthyjunkie.com Vitamin B supplements have no effect in preventing cancer in women, a U.S. study suggests.In Wednesday's issue of the Journal of the American Medical Association, Dr. Shumin Zhang of Brigham and Women's Hospital and Harvard Medical School in Boston and her colleagues studied 5,442 U.S. female health professionals with an average age of 63.
"This study shows that supplementation with the combined B vitamins provided no beneficial effect and no harmful effect," said Zhang."So in terms of cancer risk, this may not be an effective approach."In the study, researchers randomly assigned women with cardiovascular disease or risk factors such as high blood pressure to take a daily supplement of vitamins B6, B12 and folic acid or a placebo between April 1998 and July 2005.
"A total of 379 women developed invasive cancer (187 in the active treatment group and 192 in the placebo group)," the study's authors wrote."Compared with placebo, women receiving the active treatment had similar risk of developing total invasive cancer, breast cancer, or any cancer death."
Leafy greens for folate
Among women 65 and older, those taking B vitamins daily were 25 per cent less likely to develop cancer and 38 per cent less likely to get breast cancer.It's not clear whether the effect was simply due to chance, Zhang said, noting the study was not designed to look at age differences. More research is needed to determine whether B vitamins help in cancer prevention among older women.
Other studies suggest that people who eat foods rich in folate may lower their cancer risk, said Dr. JoAnn Manson of Brigham and Women's Hospital, who also took part in the study.Folate, also known as vitamin B9, is used to make healthy new cells. It is found naturally in leafy green vegetables such as spinach, citrus fruits and beans. Squash is another source of B vitamins and folate, said Andrea Holwegner, a registered dietician in Calgary.
Dietary supplements offer the vitamin in the synthetic form of folic acid.Folate deficiency has also been linked to neural tube defects, in which the central nervous system fails to develop fully in the fetus, leading to defects such as spina bifida.The Canadian government introduced mandatory fortification of whole-grain breads, cereals, flour, cornmeal and pasta with folic acid in 1998. Since then, the rate of birth defects such as spina bifida has declined, according to Health Canada.