Health experts once trumpeted folic acid, but now warn against taking too much of a good thing, the Economist reports. For more than 10 years, aspiring mothers have been told to down double the recommended dose with vitamin pills, and some countries have added folic acid to grain products. It's worked, too: Spina bifida is down in US babies by 31% since 1998. But now experts say excess folic acid could exacerbate certain cancers.
Folic acid, found in foods like spinach and oranges, is converted to folate by the liver, but it can only do so in limited amounts. Sticking to the recommended intake of 0.4 mg is safe, but consuming some cereals can push doses up to 0.8 mg—which has led the EU to halt its grain fortification programs. Pregnant women are still encouraged to take their folic acid pills, but for the rest of us, the Economist says, “the message is clear: eat your spinach.”