The Vitamins Involved in One-Carbon Metabolisms are Associated with Reduced Risk of Breast Cancer in Overall and Subtypes.

Background: Some micronutrients like folate, vitamin B12, B6, and B2 are the source of coenzymes, which participate in one-carbon metabolism. Any disruption in this metabolism can interfere with DNA replication, repair and regulation of gene expression and ultimately promote the likelihood of carcinogenesis. This study aimed at investigating the relationship between the intakes of micronutrients involved in one-carbon metabolism with breast cancer (BrCa) and its subtype's odds. Methods: Nutrients' intake from diet and supplements were collected through interviewing 151 cases and 154 controls by a 168-item semiquantitative food frequency questionnaire. Logistic regression was used to determine the relationship between dietary and/or total intake of studied nutrients and odds of BrCa and its subtypes. Results: After adjusting the effects of confounding variables in the models, the odds of BrCa was significantly lower in the highest intake quartile compared with the lowest quartile for total intake of vitamin B2 (OR = 0.17, 95% CI, 0.07-0.39; P _trend  < 0.001), vitamin B6 (OR = 0.11, 95% CI, 0.05-0.27; P _trend  < 0.001), vitamin B12 (OR = 0.20, 95% CI, 0.09-0.43; P _trend  < 0.001) and folate (OR = 0.09, 95% CI, 0.04-0.21; P _trend  < 0.001). Also, those with the highest quartile of vitamin B6, B12, B2 and folate intake compared with the lowest quartile were less likely to develop estrogen receptor (ER)+ and progesterone receptor (PR)+ subtypes, ER- status, PR- and human epidermal growth factor receptor 2 (HER2)+ subtypes and HER2- status. Conclusion: High intakes of vitamins B2, B6 and folate are associated with reduced odds of BrCa in overall and all ER, PR and HER2 subtypes. Also, high intakes of vitamin B12 reduced the odds of all subtypes of BrCa except ER- subtype.