A type of vitamin E found in nuts may prevent asthma attacks by reducing airway inflammation.
Sufferers of the common breathing condition taking it as part of a US study were also found to have less sticky mucus in their lungs.
Experts say the findings raise the possibility of asthma being kept under control by changing diet or taking a supplement.
The form of vitamin E that brought these beneficial effects is gamma-tocopherol, which is abundant in nuts such as walnuts and pecans and in the legume peanut, as well as seed oils such as corn, soybean and sesame.
This type has drawn little attention compared with alpha-tocopherol, the form most commonly found in vitamin E supplements.
“We started looking into vitamin E because epidemiologic data suggested that people with high amounts of vitamin E in their diet were less prone to asthma and allergic disease,” said senior study author Professor Michelle Hernandez from the University of North Carolina School of Medicine.
Researchers started looking into vitamin E because previous studies suggested that people with high amounts of vitamin E in their diet were less prone to asthma and allergic disease.
However, they also knew that the alpha isoform seems to be associated with an increased risk for hemorrhagic stroke, they said. So they began looking more closely at gamma tocopherol.
“While the alpha isoform does have antioxidant activities, gamma tocopherol has both an antioxidant and a very unique anti-inflammatory action as well,” said study first author Allison Burbank.
“That anti-inflammatory effect is what we think made the difference in this study.”
Participants in the study were randomized into two groups that received either gamma tocopherol supplement or a placebo for two weeks. At the end, they were asked to cough up sputum.
They also underwent an lipopolysaccharide (LPS) challenge, which involves inhaling a substance that causes inflammation in the lung and then coughing up more sputum.
The results were published in the Journal of Allergy & Clinical Immunology.
Source: The Guardian Newspaper