January 24, 2011

Nutrition to Blame for Asthma?

(Ivanhoe Newswire) -- Two new studies suggest nutrition may play a role in the development of asthma, but investigators say more research is needed to confirm the link.

Asthma affects as many as 300 million people and is one of the world's most common chronic diseases. Researchers estimate that by 2025, there could be an additional 100 million people living with asthma.

In the first study, a team of researchers from Greece examined the association between salty snack consumption along with TV or videogame viewing and asthma symptoms in young adolescents. They found there was a 4.8-times greater risk of having asthma symptoms when salty snacks were consumed more than three times a week. This link was even stronger in children who watched TV or played videogames more than two hours a day.

The study also showed that children who consumed a "Mediterranean diet" were less likely to have asthma symptoms. The Mediterranean diet consists of a high content of vegetables, fresh fruits, cereals and olive oil. The diet also encourages a high intake of beta-carotene; vitamins C and E; and other protective substances like selenium, flavonoids and polyphenols.

In a second study, investigators from the University of Aberdeen in the United Kingdom reviewed three dietary factors that have been thought to play a role in the increase in asthma. These factors are a changing antioxidant intake, an increasing ratio of n-6 to n-3 polyunsaturated fatty acid (PUFA) consumption, and changing vitamin D status. They also reviewed a small number of studies that suggested modifying one's diet during pregnancy might reduce the incidence of childhood asthma.

"The generally weak observational and very limited intervention data suggest that whilst there are associations between diet and asthma, the nature of the associations (with PUFA, antioxidants, nutrients, food), the timing (antenatal, infancy, childhood, adulthood), and the therapeutic potential of the associations are far from clear," Graham Devereux, M.D., Ph.D. writes. "Future studies should consider the use of dietary intervention to increase the intake of nutrients highlighted by birth cohorts (vitamin E, PUFA, vitamin D, zinc) in order to capture the complexity of dietary nutrient intake."

SOURCE: Journal of the American Dietetic Association, Jan. 2011