Folic Acid Intake and Risk of Breast Cancer

Breast cancer is the most common invasive cancer in women, and also the most common cause of death from cancer and accounts for 25.2% of all newly diagnosed cancers in the world. Breast cancer is a multifactorial disease, and in addition to hereditary and environmental conditions, nutritional status and nutritional factors such as folate, vitamin B6 and B12, and alcohol may also be related to it. In this study, with the use of search engines PubMed, Proquest, Scopus, Science Direct, and Web of Science, and the keywords of breast cancer, breast neoplasms, folic acid and vitamin B9 were searched, on 13 case-control, 10 cohort, and 1 case series studies were found during the years 2007-2018. Findings: Studies have shown that a diet rich in folate is not associated with a reduced risk of breast cancer. The effect of folate on breast cancer is contradictory; folate consumption may lead to the prevention of breast cancer in the premenopausal age, and would mainly affect the negative receptor type. However, the difference in sample size, study area, study design, and evaluation methods may lead to heterogeneity in the results of the studies. The relationship between folate and breast cancer is ambiguous, and requires further studies to consider the state of menopause and hormone receptor in order to achieve clearer results in this regard.