Even in very high amounts, folic acid is nontoxic. Nevertheless, it is recommended that women consume no more than 1,000 micrograms of synthetic folic acid a day. Larger amounts may hide the ability to quickly diagnose a rare vitamin B-12 deficiency. This condition primarily affects the elderly and can lead to neurological damage. Today, doctors can use a simple blood test to check for a vitamin B-12 deficiency.
Smoking interferes with the absorption of folic acid.
It used to be thought that birth control pills interfered with the absorption of folic acid, but now the birth control pills are very low dose and this is no longer the case. Since more than half of pregnancies are unplanned, an effort must be made to get all women of childbearing potential to take a multivitamin every day even if they are not trying to get pregnant. There is a big trend to eliminate processed carbohydrates in order to lose weight and look lean. Other foods containing folic acid include fruit, green leafy vegetables, dried beans and legumes. I've heard that children with spina bifida have learning problems.