When taken by women before becoming pregnant, folic acid can significantly reduce the risk of neural tube defects in their children. Spina bifida is the most common and well known type of neural tube defect. Unfortunately, past studies have found that the general public does not get enough folic acid in their diet. As a result, the United States and Canada have made it mandatory to add folic acid to grain products including breads, cereals, and rice. In the years after the grain products were fortified with folic acid, both countries saw a decrease in babies born with neural tube defects. Some studies have also indicated that folic acid may have the same protective effect against congenital heart defects in newborns. These defects in the heart can cause serious illness that requires intensive medical care, and in severe cases can make it impossible for the baby to live outside of the uterus.
Researchers from Canada investigated the link between folic acid and congenital heart defects by looking for changes in the rates of births with congenital heart defects before and after the fortification of grain products. Their study, published in the British Medical Journal, found that, like neural tube defects, the rate of congenital birth defects dropped.
The study reviewed the 1,324,440 births in Quebec from 1990 to 2005. During that time 2,083 infants were born with congenital heart defects, confirmed through medical records and death certificates. The mandatory addition of folic acid to flour and pasta did not begin in Canada until 1998. The 15-year period that the study included allowed the researchers to see changes in the rate of congenital heart defects before and after the folic acid addition.
The researchers found that there was a 6% decrease of congenital heart defects per year after the folic acid fortification program was in place.
The design of this study does not make it possible to determine whether the increase in folic acid consumption caused the decrease in the incidence of congenital heart defects. This study was only designed to observe changes in a population. There are other factors that can influence the rates of congenital heart defects that could not be accounted for in this study. However, these results add to mounting evidence that folic acid can help decrease the rates of a variety of birth defects.
Women of childbearing age should aim for 400 mcg (micrograms) per day, pregnant women should aim for 600 mcg per day. Folic acid or folate can be found in foods such as beans and lentils, peas, certain fruit juices, soymilk, nuts, and peanut butter. Cereals, breads, flours, and pasta are also folic acid enriched. Folic acid may also be taken through a multivitamin. If you are planning a pregnancy taking 400 mcg of a folic acid supplement is recommended to help prevent serious birth defects.
March of Dimes
Ionescu-Ittu R, Marelli AJ, Mackie AS, Pilote L. Prevalence of severe congenital heart disease after folic acid fortification of grain products: time trend analysis in Quebec, Canada.BMJ.2009 May 12;338:b1673.
Last reviewed June 2009 by Richard Glickman-Simon, MD