In 1947 scientists synthesized folic acid, a synthetic compound. In 1998, The FDA mandated that all enriched wheat flour was to be fortified with folic acid. This unilateral decision has turned into one of the worst health fiasco's in the history of our country.
It was based on data showing that low "folate" (found in green vegetables) status caused neural tube birth defects, which only affects approximately 1,500 US infants per year.
However, "folate" is not folic acid, and 30% to 40% of the US population lack the MTHFR enzyme to metabolize folic acid into folate, while 70% have a reduction of this enzyme—causing excess folic acid intake.
Human clinical trials have shown that folic acid fortification has resulted in population wide increases breast, prostate and colorectal cancers.