Vitamin E in Canola, Soybean Oils Might Lower Lung Function

Researchers at the Northwestern University say that "healthy" oils such as canola, soybean and corn reduce lung function and increase breathing problems in asthma patients.

The study shows that there might be a link between rise of vitamin E-rich oil intake in the U.S and the surge in asthma cases.

According to the researchers, gamma-tocopherol found in soy and canola oil reduces lung function while alpha-tocopherol helps lung perform better. Both gamma and alpha tocopherol are forms of Vitamin E.

Adults require about 15 mg (22.4 IU) of vitamin E per day, according to the Office of Dietary Supplements.

"Considering the rate of affected people we found in this study, there could be 4.5 million individuals in the U.S. with reduced lung function as a result of their high gamma-tocopherol consumption," said senior author Joan Cook-Mills, an associate professor of medicine in allergy/immunology at Northwestern University Feinberg School of Medicine, according to a news release.

Asthma is a chronic, lung condition that narrows the airways, according to the National Heart Lung and Blood Institute. The disease causes chest tightening, wheezing and coughing. In the U.S., about 25 million people suffer from asthma, of which at least 7 million are children.

The level of gamma-tocopherol in blood sample of people living in the U.S. is about four times higher than those living in European countries. According to the researchers, countries with higher levels of alpha tocopherol consumption have lower incidence of asthma.

Previous research by Cook-Mills had found that alpha tocopherols are associated with better lung function in mice. In 2012, she found a mechanism that explained how gamma tocopherol increased inflammation in lungs. Inflammation in lungs makes breathing difficult.

The present study was based on data from 4,526 individuals from the Coronary Artery Risk Development in Young Adults Study (CARDIA). Researchers looked at the levels of gamma tocopherol and lung function of these individuals. The team found that high level of gamma-tocoperol, around 10 micromolar in the blood plasma, was linked to a 10 to 17 percent lower lung function.

The study is published in the journal Respiratory Research.