A Canadian study has challenged the use of corn and safflower oils as healthy substitutes for saturated animal fats, saying the oils may increase the risk of heart disease.
In a paper published Monday in the Canadian Medical Assn. Journal, researchers concluded that polyunsaturated vegetable oils that were rich in omega-6 linoleic acid, but relatively poor in omega-3 alpha-linolenic acid, were not associated with beneficial effects on heart health.
Specifically, authors said a review of recent research suggested that though omega-6 linoleic acid lowered serum cholesterol levels, it also seemed to increase the risk of coronary artery diseases.
Study authors Richard Bazinet, a professor of nutrition at the University of Toronto, and Dr. Michael Chu, a heart surgeon at the London Cardiac Institute in Ontario, said it was unclear why the oils increased health risks. However, they said it might have to do with the chemical process known as oxidation.
"The detrimental effects of linoleic acid were seen in participants who were smokers and those who consumed alcohol, people likely to be under increased oxidative stress," the authors wrote.
In Canada, corn and safflower oil are used in foods such as mayonnaise, creamy dressings, margarine and chips.
The federal Food Directorate allows the food industry to label products with corn and safflower oil as healthy replacements for saturated fats. Study authors are now asking the government to reconsider its labeling eligibility.