A You can't get too much from foods that naturally contain folate. You should not get more than 1,000 micrograms of folic acid a day, unless your doctor prescribes a higher amount. Too much folic acid can hide signs that you lack vitamin B12, which can cause nerve damage.

A Folate deficiency caused by a lack of dietary folate is more common in people who have a generally unbalanced and unhealthy diet, people who regularly misuse alcohol, and people following a fad diet that does not involve eating good sources of folate.

A Taking folic acid at high doses can hide a vitamin B12 deficiency. So these vitamins are often taken together.