A significant number of vegetable oils available in the market that advertise their health aspect can sometimes provide the opposite impact. Canadian researchers reported in the journal CMAJ that certain vegetable oils which claimed lower cholesterol can pose serious risk to the heart.
Till date, vegetable oils have been considered to be good for the heart as the polyunsaturated fats in them help reduce serum cholesterol levels and thus help protect against risk of heart disease. Citing health benefits, companies have been selling their products by assuring the consumers "a reduced risk of heart disease by lowering blood cholesterol levels."
However, Dr. Richard Bazinet from the University of Toronto and colleagues found that most of the oil companies were not meeting the recommended ratio of two important polyunsaturated fatty acids needed to serve the purpose: omega-6 linoleic acid and omega-3 α-linolenic acid. Some of the oils, like corn and safflower oils, contained high levels of omega-6 acid but had very low levels of omega-3 acid. Such oils cannot provide any health benefits to the heart, said the authors of the study.
To explain the hidden risks associated with such types of vegetable oils, researchers explained a study published in February this year. During the study, participants stopped taking saturated fat and switched to safflower oil or oil margarine. Though the treatment helped reduce the serum cholesterol levels of the participants (up to 8 and 13 percent), mortality rates due to cardiovascular diseases or coronary artery disease shot up considerably.
"When the new results were added to a meta-analysis, the net result was a borderline 33 per cent increase in heart disease risk for oils rich in omega-6 and poor in omega-3, with absolutely no evidence of a benefit as is implied by the health claim," lead author of the study, Bazinet said in a University news release.
Concerned with their findings, the authors recommended the public to be more careful while purchasing vegetable oils. "This is important information for people buying certain foods because of the heart benefits when really, that's not accurate," Bazinet, explained. "While most of these foods are a good choice, there are a few notable exceptions."