Say No to Corn Oil: Common Edible Oils May be Linked to Asthma
Not so long ago, scientists thought the natural antioxidant, vitamin E, was a sort of wonder drug. There was a large clinical trial, for example, that looked at men's consumption of supplemental vitamin E and the incidence of prostate cancer. They hoped vitamin E might prevent the disease. But it didn't pan out. Some studies even seemed to suggest that higher consumption of vitamin E is actually linked to worse health outcomes, rather than better ones. At best, results from various trials have been mixed.
It was all a little confusing, and many people pointed in frustration at this latest example of hyped benefits for a particular food, which later proved incorrect. Part of the problem stems from the term vitamin E itself. Vitamin E is not a single substance. Rather, it is a collection of related chemicals; eight different fat-soluble compounds with antioxidant activities. More careful research has differentiated among various forms. Some results suggest that different forms of vitamin E may have distinctly different effects in the body.
Now a large study by Northwestern University researchers shows that certain cooking oils may be linked to an increased risk of the inflammatory lung disease, asthma. Specifically, common cooking oils such as corn, soybean and canola oils all contain high levels of a form of vitamin E known as gamma-tocopherol. This form of vitamin E is linked to decreased lung function.
On the other hand, alpha-tocopherol, found in cooking oils such as olive and sunflower, is associated with better lung function. In other words, if asthma is a concern in your family, you'd do well to switch to olive oil for all your cooking needs. (I've been saying it for years!) And toss the canola or corn oil away. It's not serving your health and may be making your condition worse.
Investigators say this is the first time scientists have shown that the type of vitamin E you consume can affect lung function significantly. The study has important implications for public health. Asthma is on the rise in the United States, and it's one of several inflammatory diseases that have increased in synch with the switch to high consumption of soybean, corn, and canola oils in America. "People in countries that consume olive and sunflower oil have the lowest rate of asthma and those that consume soybean, corn and canola oil have the highest rate of asthma," researcher Joan Cook-Mills said. "When people consume alpha-tocopherol, which is rich in olive oil and sunflower oil, their lung function is better."