Higher dietary intake of vitamin B6 is associated with a reduction in breast cancer risk, particularly among premenopausal women and of estrogen receptor (ER)-negative tumors, a new study among Taiwanese women suggests.
The case-control study included 391 breast cancer cases and 782 control subjects enrolled at the Tri-Service General Hospital in Taipei, Taiwan (1). The authors examined the dietary vitamin B6 intake with overall breast cancer risk and breast cancers stratified by hormone receptor status. They derived the energy adjusted intake of vitamin B6 from a food frequency questionnaire, inquiring how often participants consumed individual food items (frequency of consumption) during either the preceding year (control subjects) or one year before their breast cancer diagnosis (cancer patients). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic progression.
The study was based on the fact that B vitamins, including B6, are coenzymes that are important for DNA integrity and stability, and that deficiencies in B vitamins may promote carcinogenesis. Vitamin B6 plays a crucial role for DNA synthesis, repair, and methylation. Apart from this, it is a cofactor for the synthesis of glutathione from homocysteine. Glutathione is involved protecting cells from DNA damage and vitamin B6 has been shown to reduce oxidative stress as well as cell proliferation and angiogenesis. Conducting the study of the association between dietary intake of vitamin B6 an breast cancer risk, the authors examined this with respect to the hormone receptor status of breast tumors to figure out to what degree low intake of B vitamins is linked to ER-negative and progesterone receptor (PR)-negative breast tumors.
An inverse association was observed between dietary intake of vitamin B6 and significantly lower risk of breast cancer, particularly evident among premenopausal women. The analysis of cases stratified by ER status of breast tumors revealed that the reduction in risk was more pronounced among women with ER-negative breast tumors. The biological plausibility of vitamin B6’s protective effect against breast cancer risk is supported by a solid body of data. Further prospective studies are needed to confirm and elucidate the results.