Vitamin E Rich Oils Like Canola Trigger Lung Inflammation and Possibly Asthma

Increased consumption of vitamin E rich oils is linked to reduced lung function and possibly asthma, a new study reveals.

Researchers at North-western  Medicine  reveal that vitamin  E in oils like Canola, soybean and corn can cause lung inflammation and in certain cases even asthma.  The study found no such similar link in vitamin E present in olive and sunflower oils. The researchers claim that vitamin E in these two oils enhances the lung function. 

The researchers highlight the fact that the health effects of vitamin E depends largely on its form. The kind of vitamin E seen in soybean, corn and canola oils is called gamma-tocopherol, which has an adverse impact on lung function.  The other form of vitamin E seen in olive and sunflower oils is called the alpha-tocopherol and this boosts the lung function. This is one of the first studies to reveal the strong association between gamma-tocopherol and the reduced lung function.

"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.

In this study the researchers analyzed 4,526 subjects who were a part of the Coronary Artery Risk Development in Young Adults Study (CARDIA). Prior to this, the researchers had conducted a study on mice, which revealed that alpha-tocopherol lowered lung inflammation and offered protection to the lungs and on the other hand gamma-tocopherol elevated the lung inflammation and airway hyper responsiveness, a characteristics of asthma. Based on this test, Cook-Mills was sure that they show similar effects in humans.

To proceed with the study the researchers examined the CARDIA results at four intervals from baseline to 20 years. They also examined the blood plasma at three intervals from baseline to 15 years. This was done for the lung function test. An increased level of gamma-tocopherol was notice; 10 micromolar in the blood plasma was linked with 10-1 percent of reduced lung function. 

"The blood plasma showed how much they had acquired in their tissues," Cook-Mills said. "You get vitamin E from your diet or supplements. A 10 percent reduction in lung function is like an asthmatic condition. People have more trouble breathing. They take in less air, and it's harder to expel. Their lungs have reduced capacity."

Over the last 40 years there has been an uptick in the rate of asthma among Americans.  And this rise coincides with the change made in the diet from lard and butter to soybean, canola and corn oils.

The finding was presented at the Oxidants and Antioxidants in Biology World Congress. It was also published in the journal Respiratory Research.