A form of vitamin E found in vegetable oils like corn and canola may worsen lung function, while another form typically found in olive oil may protect it, a new study suggests. The findings may help explain why studies of the health effects of the vitamin have had conflicting results.
Vitamin E comes in various forms called tocopherols, commonly found in fats and oils. Supplements of the vitamin may contain a single type of tocopherol, or a mix.
The new research, published in Respiratory Research, found that a form of the vitamin called gamma tocopherol, the kind in corn, canola and soybean oils, was linked to poor lung function in adults. But another form of the vitamin typically found in olive and sunflower oils, called alpha tocopherol, seemed to have a beneficial effect on lungs.
“It’s mind-blowing that there’s this disparity,” said Dr Clifford W Bassett, an allergist and assistant clinical professor of medicine at the New York University School of Medicine. “What’s interesting is that most people taking vitamin E never stop to ask where it’s from.”
Dr Bassett said the findings suggest that consumers who use the vitamin and doctors who recommend it might need to be “more acutely aware” of its source and formulation. That information is sometimes listed on the labels of supplements, but not always.
Vitamin E, considered a powerful antioxidant, is thought to play a role in cardiovascular and neurological health. There is also some evidence that it may help protect against asthma and other respiratory problems. But studies have also suggested that taking vitamin E has no effect on lung health, or even a potentially harmful one.
In research over the years at Northwestern University Feinberg School of Medicine, Joan Cook-Mills, an associate professor, has found that in addition being an antioxidant, vitamin E appears to play a role in inflammation. The vitamin influences a protein that allows white blood cells to exit the bloodstream and enter tissues, including cells in the lung, a critical step in the inflammatory response.
But different forms of the vitamin do not have the same effect. Gamma tocopherol increases the activity of the protein, and alpha tocopherol lowers it.
As a result, the two forms of vitamin E can have a drastically different impact on inflammation, Dr Cook-Mills said. For example, gamma tocopherol can set off “hyper responsiveness” in the airways, a common feature of asthma,