Taking folic acid supplements for at least a year before conception is associated with reduction in the risk of premature birth, according to a study by Radek Bukowski (from the University of Texas Medical Branch, United States of America) and colleagues.

Although most pregnancies last about 40 weeks, many babies (for example around 12% in the United States) are born before 37 completed weeks of pregnancy. Babies born prematurely are less likely to survive than full-term babies and are more likely to have breathing difficulties and learning or developmental disabilities. Currently, there are no effective methods of prevention or treatment of premature (preterm) birth, but previous studies have suggested that lower concentrations of folate (folic acid) are associated with shorter duration of pregnancy. Bukowski and colleagues therefore tested this idea, by analyzing data collected from a cohort of nearly 35,000 pregnant women.

The results of this study showed that taking folate supplements for at least one year before conception was associated with a 70% reduction in spontaneous premature birth between 20 and 28 weeks (a reduction from 0.27% to 0.04%), and a 50% reduction between 28 and 32 weeks (reduction from 0.38% to 0.18%), as compared to the rate of preterm birth when mothers did not take additional folate supplementation. Folate supplementation for less than a year before conception was not linked to a reduction in the risk of premature birth in this study, and folate supplementation was not associated with any other complications of pregnancy.

Journal reference: Bukowski et al. Preconceptional folate Supplementation and the Risk of Spontaneous Preterm Birth: A Cohort Study. PLoS medicine, 2009; 6 (5): e1000061

Folic acid, or vitamin B9, essential for red blood cell health and long known to reduce the risk of spinal birth defects, may also suppress allergic reactions and lessen the severity of allergy and asthma symptoms, according to new research from the Johns Hopkins Children's Center.

In what is believed to be the first study in humans examining the link between blood levels of folate- the naturally occurring form of folic acid - and allergies, the Hopkins scientists say results add to mounting evidence that folate can help regulate inflammation. Recent studies, including research from Hopkins, have found a link between folate levels and inflammation-mediated diseases, including heart disease. A report on the Hopkins Children's findings appears online ahead of print in the Journal of allergy & Clinical Immunology.

Cautioning that it's far too soon to recommend folic acid supplements to prevent or treat people with asthma and allergies, the researchers emphasize that more research needs to be done to confirm their results, and to establish safe doses and risks.

Reviewing the medical records of more than 8,000 people ages 2 to 85 the investigators tracked the effect of folate levels on respiratory and allergic symptoms and on levels of IgE antibodies, immune system markers that rise in response to an allergen. People with higher blood levels of folate had fewer IgE antibodies, fewer reported allergies, less wheezing and lower likelihood of asthma, researchers report.

"Our findings are a clear indication that folic acid may indeed help regulate immune response to allergens, and may reduce allergy and asthma symptoms," says lead investigator Elizabeth Matsui, M.D. M.H.S., pediatric allergist at Hopkins Children's. "But we still need to figure out the exact mechanism behind it, and to do so we need studies that follow people receiving treatment with folic acid, before we even consider supplementation with folic acid to treat or prevent allergies and asthma."

The current recommendation for daily dietary intake of folic acid is 400 micrograms for healthy men and non-pregnant women. Many cereals and grain products are already fortified with folate, and folate is found naturally in green, leafy vegetables, beans and nuts.