An analysis published in the Canadian Medical Association Journal has suggested that allowing health claims for vegetable oils rich in omega-6 linoleic acid but poor in omega-3 a-linolenic acid should be reconsidered as these oils may actually increase the risk of heart disease.
In 2009, Health Canada’s Food Directorate approved a request from the food industry to allow the claim “a reduced risk of heart disease by lowering blood cholesterol levels” on vegetable oils and foods containing these oils.
However, the researchers referred to evidence from a study in which subjects replaced saturated fat with sources of safflower oil or safflower oil margarine which are rich in omega-6 linoleic acid but have almost no omega-3 a-linolenic acid. The results showed that although the group had significantly lowered serum cholesterol levels (down 8%-13%) compared to the baseline and control group, consistent with the health claim, rates of death from all causes of cardiovascular disease and coronary artery disease were significantly higher in the treatment group.
The researchers proposed that the health claim be modified so that foods rich in omega-6 linoleic acid but poor in omega-3 a-linolenic acid are excluded.