HealthNotes

• By Jane Hart, MD

Pregnancy News: Folic Acid Linked to Lower Autism Risk

The amount and timing of folic acid supplementation may both play a role in a pregnant woman’s risk of having a child with autism. A study in The American Journal of Clinical Nutrition found that a child’s autism risk was about 40% lower when their mothers took higher amounts of folic acid in pregnancy, particularly around the time of conception.

A child’s autism risk was about 40% lower when their mothers took higher amounts of folic acid in pregnancy

The importance of timing and amount

In this study, researchers looked at the folic acid intake of 837 mothers of children 2 to 5 years old who were enrolled in the Childhood Autism Risks from Genetics and Environment (CHARGE) study. Specifically, they looked at how much folic acid these women had consumed through supplements and cereals during the three months prior to and throughout pregnancy. The incidence of autism and delayed development were identified in the children of these women.

Results showed that women who took 600 mcg or more of folic acid each day during the first month of pregnancy had about a 40% lower risk of having a child with autism spectrum disorder compared with women who took less than that amount. These findings were strongest for participants with a specific genetic variant that interferes with folate metabolism, which was about 60% of the women.

The study authors comment, “Our findings are consistent with research that indicates folic acid's importance in improving childhood behavioral outcomes.” They add that there is a critical time period during which it is important for women to get enough folic acid and conclude that getting enough around the time of conception was linked to the greatest protective effect.

Folic acid’s healthy effects

Further evidence supports supplementation. Research suggests that folic acid supplementation in women of childbearing age is essential for helping prevent neural tube defects such as spina bifida. Though more research is still needed, preliminary research suggests that getting enough folic acid may be important for preventing behavioral conditions such as autism.

It’s important to get enough folic acid. The study authors point out that more than 95% of women of childbearing age in the United States eat less than 400 mcg of folic acid from foods each day, and they add that “the bioavailability of dietary folate is less than 60% that of folic acid” from supplements. As a result, they suggest that women eating only folate from food would probably be in the lowest category of folic acid intake, making it important that women in their childbearing years follow their doctors’/obstetricians’ advice regarding folic acid supplementation to make sure they are getting enough. Research suggests that it is essential to start supplementation well before becoming pregnant.

A mix of nutrients is important. It’s important to realize that it is not only folic acid that is important for a baby’s health but rather a variety of nutrients that add to their health and development. Taking all prescribed prenatal vitamins and minerals and eating a healthy diet rich in whole foods will help provide the mix of nutrients that are needed.

Talk with a healthcare professional. If you are a woman of childbearing age, talk with a doctor or nutritionist about the importance of folic acid and other prenatal vitamins to help optimize the health of your baby.

(Am J Clin Nutr 2012;96:80–9)