Folate is a water-soluble B vitamin that occurs naturally in food. Folic acid is the form of folate that used in supplements and added to some foods.
Folate is an important nutrient for pregnant women and women planning to become pregnant. Folate helps to reduce the risk of birth defects affecting the baby's brain and spinal cord. These are called neural tube defects.
However, folate has benefits for everyone because it:
Americans tend to assume that if a little bit of something is good, then more must be better. However, there are risks to getting too much folate, whether you are a healthy adult or a woman who is pregnant.
Find out how much folate you need, how to avoid getting too much, and which foods are the best sources.
How Much Folate Do I Need?
The recommended dietary allowances (RDAs) for folate are based on age.
How Much Is Too Much?
Eating foods fortified with folic acid and taking supplements is a good way to get enough folate. There doesn't appear to be any harm to getting lots of folate naturally from foods. However, too much folic acid may be harmful to healthy adults and women who are pregnant.
Folic acid was added to the food supply in 1998. As a result, Americans increased their folic acid intake by more than 200 micrograms a day.
If you are pregnant:
Folic acid reduces the incidence of neural tube birth defects when taken during the first 8 weeks of pregnancy. But, many women do not know that they are pregnant until later than 8 weeks. That is why all women of reproductive age are advised to take 400 micrograms of folic acid a day, in addition to eating a balanced diet. Only 500 micrograms a day are needed to reduce the risk of neural tube defects.
Women in their second and third trimesters also benefit from folic acid supplements to help with increased cell growth. It takes just 450 micrograms of folate a day to maintain normal folate levels during the second trimester. This can come from a combination of dietary folate and folic acid.
If folic acid is so important during pregnancy, why not get as much as possible? Extra folic acid in your body during pregnancy may affect your baby after birth. Recent studies have suggested that too much folic acid during pregnancy could have some effects on your baby's health during childhood and into adulthood. The question of how much is too much is still being debated.
If you are a healthy adult:
The upper level of tolerance (UL) for folic acid is 1,000 micrograms a day for adults. This is because high folic acid levels with low vitamin B12 levels may lead to mental impairment.
Excess folic acid intake may also increase the risk of some cancers. For example:
Food Sources of Folate
Folate is found in fruits, vegetables and many foods that are a good source of protein. It must be broken down in the gut before it can be absorbed.
Sources: USDA Nutrient Database, release 18; NIH Dietary Supplement Fact Sheet, 2009
Many foods are fortified with folic acid. It was added to all enriched grain foods in 1998 to help reduce the incidence of neural tube defects. It is digested and absorbed more easily than folate. It takes only 0.6 micrograms of folic acid to equal 1 microgram of folate.
The Bottom Line -- Go Natural
Eat foods that are high in naturally-occurring folate. If you choose to take a folic acid-supplement, choose one that has no more than 400 micrograms a day unless your doctor advises you otherwise. Also, consider limiting your intake of foods fortified with 100% Daily Value (DV) of folic acid to avoid getting too much.
Although folic acid was added to our food supply to target reproductive-age women, Americans are getting an average of 200 micrograms a day through fortified foods. You can easily meet your needs with a balanced diet that has only naturally occurring folate.
Melissa Lumish is a dietetic intern at Brigham and Women's Hospital. She graduated with a B.S. in Human Biology, Health & Society and a concentration in dietetics from Cornell University.
Category: Food for Thought
© 2014 Aetna Inc.