Vitamin B6 has been associated with reduced risk of breast cancer, with inconsistent results. Now a new study has reported that postmenopausal women in the top fourth of circulating vitamin B6 levels have a lower risk of hormone receptor positive (ER+/PR+) breast cancer than women in the lowest fourth.
Dietary vitamin B6 and risk of breast cancer
All of the recent studies that have been performed regarding consumption of vitamin B6 in the diet have been performed in Chinese populations:
- A case-control study among Chinese women in Guangdong reported that women in the highest fourth of dietary vitamin B6 intake had a 54% lower risk of breast cancer than women in the lowest quartile. The inverse association between vitamin B6 and breast cancer risk did not differ by estrogen receptor (ER) or progesterone receptor (PR) status.
- A Taiwanese case-control study reported that women in the highest third of dietary vitamin B6 intake had a 46% lower risk of breast cancer than women in the lowest tertile. In addition, higher vitamin B6 intake was associated with a significantly lower risk of developing ER- breast tumors.
- A prospective study using data from the Shanghai Women's Health Study reported that dietary intake of most B vitamins, including vitamin B6, was not associated with breast cancer risk.
Supplemental vitamin B6 and risk of breast cancer
U.S. studies typically examine consumption of supplemental or total (diet plus supplements) vitamin B6 in association with breast cancer risk:
- A study within the Supplementation With Folate, Vitamins B6 and B12 and/or Omega-3 Fatty Acids secondary prevention trial investigated the effects of vitamin supplements (including B6) on cancer outcomes among survivors of cardiovascular disease. After 5 years of supplementation, no association was found between cancer risk or mortality and supplementation with B vitamins.
- A study using initially cancer-free participants drawn from the Women's Health Study cohort was designed to investigate the associations between plasma concentration of pyridoxal 5-phosphate (the principal active form of vitamin B6) and risk of breast cancer. Participants provided blood samples at baseline. Plasma concentrations of vitamin B6 were found to be associated with lower risk of postmenopausal breast cancer.
- A U.S. prospective study including postmenopausal women enrolled in the Cancer Prevention Study II Nutrition Cohort reported no association between total vitamin B-6 intake (from both food and supplements) and risk of breast cancer.
Latest research finds high circulating vitamin B6 linked to lower risk
The study referenced at the beginning of this news article was designed to investigate the association of prediagnostic circulating vitamin B6 with risk of breast cancer in postmenopausal women. The study included 706 breast cancer cases and 706 matched cancer-free controls in the Multiethnic Cohort in Hawaii and Southern California. Plasma concentrations of vitamin B6 were assessed with a blood draw at baseline. Circulating vitamin B6 might represent a more accurate assessment of vitamin B6 intake than an estimate based on a food and supplement questionnaire.
Women in the top fourth of vitamin B6 levels were found to have a 30% lower risk of invasive breast cancer than women in the lowest quartile. While the analysis was conducted according to hormone receptor status, the finding appeared to be limited to cases with hormone receptor positive tumors. Also, no association was found when blood was collected more than one year before diagnosis. The authors conclude that higher circulating levels of vitamin B6 are associated with lower risk of postmenopausal breast cancer.
Please see our article on what ER+/PR+ breast cancer patients and survivors should eat for more information.
Selected breast cancer studies
B Vitamin and/or ω-3 Fatty Acid Supplementation and Cancer
Touvier M. B Vitamin and/or ω-3 Fatty Acid Supplementation and Cancer. Archives of Internal Medicine. American Medical Association (AMA); 2012; 172:540 10.1001/archinternmed.2011.1450
Dietary folate, vitamin B6, vitamin B12 and methionine intake and the risk of breast cancer by oestrogen and progesterone receptor status
Zhang C, Ho SC, Chen Y, Lin F, Fu J, Cheng S. Dietary folate, vitamin B6, vitamin B12 and methionine intake and the risk of breast cancer by oestrogen and progesterone receptor status. British Journal of Nutrition. Cambridge University Press (CUP); 2011; 106:936-943 10.1017/s0007114511001140
Dietary B Vitamin and Methionine Intakes and Breast Cancer Risk Among Chinese Women
Shrubsole MJ, Shu XO, Li H, Cai H, Yang G, Gao Y, et al. Dietary B Vitamin and Methionine Intakes and Breast Cancer Risk Among Chinese Women. American Journal of Epidemiology. Oxford University Press (OUP); 2011; 173:1171-1182 10.1093/aje/kwq491
Folate and other one-carbon metabolism–related nutrients and risk of postmenopausal breast cancer in the Cancer Prevention Study II Nutrition Cohort
Stevens VL, McCullough ML, Sun J, Gapstur SM. Folate and other one-carbon metabolism–related nutrients and risk of postmenopausal breast cancer in the Cancer Prevention Study II Nutrition Cohort. The American Journal of Clinical Nutrition. Oxford University Press (OUP); 2010; 91:1708-1715 10.3945/ajcn.2009.28553
Plasma folate, vitamin B-6, vitamin B-12, and risk of breast cancer in women
Lin J, Lee I, Cook NR, Selhub J, Manson JE, Buring JE, et al. Plasma folate, vitamin B-6, vitamin B-12, and risk of breast cancer in women. The American Journal of Clinical Nutrition. Oxford University Press (OUP); 2008; 87:734-743 10.1093/ajcn/87.3.734