Folic acid plays a key role in cell synthesis and repair. Dietary supplementation with folate before conception reduces the risk of neural tube defects such as anencephaly and spina bifida. Most of the published literature suggests that plasma folate levels are inversely associated with the risk of breast cancer. The mechanisms by which folate deficiency contributes to carcinogesis are unclear. On balance most of the scientific evidence suggest that folic acid has a protective role against the development of breast cancer.