Asthma “not linked” to vitamin A deficiency

Friday June 24th, 2011

Vitamin A deficiency does not increase the risk of asthma, new research has suggested.

A study published online in the European Respiratory Journal reveals findings that are contrary to previous understanding about the association between vitamin A and the onset of asthma.

Scientists from Nepal and Johns Hopkins University in the USA assessed more than 5,000 people living in a rural area of Nepal, many of whom suffered from chronic malnutrition, to see if taking vitamin A supplements at an early age altered the risk of developing of asthma later in life.

Previous research has shown that vitamin A deficiency harms the development of the lungs.

All the participants were children who had taken part in two different studies. In the first, half the youngsters were given vitamin A supplements during their pre-school years and half received a placebo.

In the second study, one third of the children’s mothers each received vitamin A supplements before, during and after pregnancy, one third received beta-carotene and one third received no supplements.

Between ten and 15 years after the studies were completed, the researchers used questionnaires and a spirometry test to assess lung function to establish if the children had asthma.

There was no difference between the children receiving supplements and those who did not receive them, while spirometry tests results also showed that vitamin A deficiency did not impact upon the risk of wheezing, cough, phlegm and obstructive airways.

Dr William Checkley, lead author from the John Hopkins University, said: "Contrary to what has previously been thought, our findings show that vitamin A deficiency does not lead to an increased risk of asthma. Whilst vitamin A deficiency does affect lung development adversely, we have found no evidence that it is linked with the development of asthma."

Supplementation with vitamin A early in life and subsequent risk of asthma. William Checkley, Keith P West, Robert A Wise, Lee Wu, Steven C LeClerq, Subarna Khatry, Joanne Katz, Parul Christian, James M Tielsch, Alfred Sommer. European Respiratory Journal June 2011 DOI: 10.1183/09031936.00006911

Tags: Allergies & Asthma | Asia | Child Health | North America | Respiratory

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