Possible link between folic acid and childhood asthma

Friday September 19th, 2008

Pregnant women may be influencing their children's risk of developing asthma and allergy by taking folic acid supplements, researchers warned today.

The findings shed new light on the policy of encouraging folic acid supplements during pregnancy.

The vitamins are taken to prevent diseases such as spina bifida - but the price of preventing this disease may be a risk of asthma, according to the research.

A team from the National Jewish Medical and Research Center, Denver, Colorado, USA, gave pregnant laboratory animals a range of different diets and supplements.

A higher rate of asthma was seen in the offspring of animals given folic acid supplements and foods containing similar substances than others. The offspring had "more severe allergic airway disease", the researchers report.

Findings are published in the Journal of Clinical Investigation. They indicate that a mother's diet can affect the development of the baby's immune system predisposing it to allergic airway disease, says researcher Dr David Schwartz.

"It also suggests the dramatic increase in asthma during the past two decades may be related in part to recent changes in dietary supplementation among women of childbearing age," he said.

Asthma has nearly doubled in the US over the past 25 years, now affecting about 11 per cent of the population. Co-author Dr John Hollingsworth of Duke University School of Medicine, Durham, North Carolina, USA, says this rise is largely unexplained.

But, "there seems to be a crucial stage, during development in utero, when a young mouse is susceptible to epigenetic changes that can alter its immune system," he said.

In 1992, the US Public Health Service recommended that all women of childbearing age take folic acid every day to reduce the risk of birth defects, and in 1996 it was added to flours, breads and other grains.

The experts do not advise any change to the recommendations at present because of the benefits of folic acid in preventing birth defects.

Schwartz, D., Hollingsworth, J. et al. The Journal of Clinical Investigation, published online September 18, 2008, and in the October print issue.

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Tags: Allergies & Asthma | Child & Adolescent Health | Women’s Health & Gynaecology

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