Folate and (folic acid) are water soluble B vitamins. Derived from the the Latin word "folium" for leaf, researcher Lucy Wills identified the nutrient nearly 70 years ago as the nutrient needed to prevent the anemia of pregnancy.

Folate is necessary for the production and maintenance of new cells. This is especially important during periods of rapid cell division and growth such as infancy and pregnancy. Because folate is needed to synthesize DNA, a deficiency of folate may result in damage to DNA that may lead to cancer.  

Folate, along with vitamin B6 and vitamin B12, are important for heart health as they help to reduce levels of homocysteine - an amino acid that increases the risk for heart disease and stroke.

Folic acid is very important for all women who may become pregnant. Adequate folate intake during the periconceptual period, the time just before and just after a woman becomes pregnant, protects against a number of congenital malformations including neural tube defects.

References

National Institutes of Health, Office of Dietary Supplements. Van Guelpen B (2007). "Folate in colorectal cancer, prostate cancer and cardiovascular disease". Scand J Clin Lab Invest 67 (5): 459–73. doi:10.1080/00365510601161513. PMID 17763182.