Vegetable Oils Aren't All Healthy: Increased Risk of Heart Disease

Not all vegetable oils are as healthy as you might think. Scientists have discovered that some vegetable oils may actually increase the risk of heart disease. The findings reveal it's more important than ever to assess foods that claim to be "healthy" but are, in reality, quite the opposite.

Replacing saturated animal fats with polyunsaturated vegetable oils has become a common practice in the food industry. It can reduce serum cholesterol levels and prevent heart disease. In order to assess these vegetable oils, though, Health Canada's Food Directorate decided to conduct a study to see if these oils did indeed lower blood cholesterol oils.

So what's the verdict? It turns out that corn and safflower oil, which are rich in omega-6 linoleic acid but contain almost no omega-3 a-linolenic acid, are not associated with beneficial effects on heart health. In fact, a recent study revealed that an intervention group that replaced saturated fat with sources of safflower oil or safflower oil margarine had increased rates of death from all causes of cardiovascular disease and coronary artery disease.

"Careful evaluation of recent evidence, however, suggests that allowing a health claim for vegetable oils rich in omega-6 linoleic acide but relatively poor in omega-3 a-linolenic acid may not be warranted," said Richard Bazinet, one of the researchers, in a news release.

Omega-6 linoleic acid is found in corn and safflower oils as well as foods such as mayonnaise, margarine, chips and nuts. Canola and soybean oils contain both linoleic and a-linolenic acids and are the most common forms of oil in the Canadian diet.

What is perhaps more intriguing is the fact that while the rates of disease increased, the control group had serum cholesterol levels that were significantly decreased--by about 8 to 13 percent. This seems to indicate that what the oil is made out of is key. Food rich in omega-6 linoleic acid but poor in omega-3 a-linoleic oil are probably not beneficial in the long run.

The findings reveal a little bit more about these vegetable oils and show that, in fact, the types of oils we consume greatly impact our health.

The findings are published in the Canadian Medical Association Journal.