Folic acid is a vitamin that best-known for the prevention of neural tube defects in newborn babies, thus many food products are fortified with folic acid in developed countries. Robert Clarke, from the University of Oxford (United Kingdom), and colleagues assessed data collected on 50,000 men and women involved in 13 clinical trials of folic acid supplementation. The team found that those who took daily folic acid for five years or less were not significantly more likely to develop cancer, as compared to those who took placebo. Among those with the highest average intake of folic acid (40 mg per day), no significant increase in overall cancer incident was noted either. The study authors conclude that: “Folic acid supplementation does not substantially increase or decrease incidence of site-specific cancer during the first 5 years of treatment.”