The Facts About Folic Acid Supplementation and Asthma

Folic acid's role in prenatal nutrition has been clear for many decades, as pregnancy increases the need for folic acid up to 76%. Adequate folic acid supplementation reduces the risk of spina bifida in the infant.

Recently, experimental animal interventions have suggested that folic acid intake that exceeds the recommended dose may increase risk of respiratory disease in offspring. Some (but not all) studies have also found adverse relationships in humans. This has created a concern that excess folic acid supplementation may cause asthma.

Researchers from the University of California at Los Angeles have conducted a study to assess the use of folic acid supplementation in a population of Hispanic women residing in the Los Angeles area. They examined early and late initiation of folic acid supplementation and its potential relationship to respiratory disease in children in the first 3 years of their lives. Their findings are encouraging.

This topic is of importance because approximately 40% of American women who become pregnant consume less than the recommended daily intake of folic acid.

Out of 1200 women who participated in the study, the researchers noted no association between the timing of supplementation initiation and adverse respiratory outcomes in children.

Their findings indicate that in women who have atopic triad, early prenatal supplementation may prevent wheeze in their children. When these women waited to start folic acid until late in their pregnancies, their offspring's risk of developing wheeze was 1.7 to 1.9 times the risk of children whose atopic mothers started folic acid early. These findings are tempered by the fact that only 17 atopic women started folic acid late, representing a small portion of participants.

Additionally, in participants who did not initiate folic acid supplementation in the first trimester of pregnancy, the risk for wheeze during the first 3 years of life was increased.

The researchers reported that their findings contradict studies in other nations that have associated folic acid supplementation with increased asthma risk. Their findings do align with some studies that have not associated folic acid supplementation with asthma or wheeze.

This article appears in Maternal and Child Health Journal.

Reference

Alfonso VH, Bandoli G, von Ehrenstein O, et al. Early Folic Acid Supplement Initiation and Risk of Adverse Early Childhood Respiratory Health: A Population-based Study. Matern Child Health J. 2017 Sep 8. doi: 10.1007/s10995-017-2360-6. [Epub ahead of print]