Only 400 μg per day of vitamin B9, or folic acid, taken prenatally can help the fetus to develop normally, avoiding miscarriage and reducing the risk of birth defects by nearly three fourths. In particular, it helps prevent spina bifida, a condition in which some of the vertebrae that ordinarily cover the spinal cord don’t fully close, leading to physical problems and neurological and cognitive deficits.
However, there are other birth defects that folic acid, which is a part of the cell division process that underlies almost all tissue formation and growth, can help prevent. It helps prevent all neural tube defects, the type of birth defect of which spina bifida is among the most common, and also congenital heart defects, cleft lip, and other conditions.
To be most useful in fetal development, folic acid should be taken early in the pregnancy—the most effective time to up B9 intake is the first four weeks after conception. Most people don’t know they’re pregnant for much of that time, which is why women who might become pregnant are generally advised to get their extra 400 μg daily, in order to be sure they’re ready. However, getting a head start—being sure to get that amount even before conception—has been shown to have benefits for the future fetus.
Moreover, folic acid is beneficial in adults as well, even men. Folic acid can help prevent colorectal cancer as well as cervical cancer. It’s good for the heart, lowering the risk of heart attack and stroke. It’s also good for a large number of other things. People worried about the effects of growing older should know B9 helps slow or prevent Alzheimer’s disease and a kind of progressive vision loss called age-related macular degeneration, as well as other signs of aging. It’s good for depression and sleep problems, nerve and muscle pain, and even AIDS.
Fortunately, folic acid is easy to get. There are supplements, but most people don’t need them. Vitamin B9 is found in leafy green vegetables, asparagus, okra, bananas, beans, oranges, lemons, organ meats, mushrooms and even yeast. By law it’s added to flour as well in the United States. Inadvertently omitting folic acid from the diet would be next to impossible.