Healthy Vegetable Oils Reduced Heart Attack Risk
Consuming omega-3 fatty acids found in some vegetable cooking oils and fish was associated with reduced heart attack risk in a Costa Rican population study, and eating omega-6 fatty acids was linked to lower blood pressure for healthy people in an international study.
The studies were separately published respectively in Circulation: Journal of the American Heart Association and Hypertension: Journal of the American Heart Association.
Both omega-3 fatty acids (alpha-linolenic acids from plant foods, EPA and DHA from some fatty fish) and omega-6 fatty acids (mainly linoleic acid) are polyunsaturated essential fatty acids that must be obtained from food because the body cannot make them sufficiently. Omega-3 fatty acids are found in found in walnuts, soybean, canola and flaxseed oils and in fish such as salmon, tuna and sardines.
Omega-6 is plentiful in soybean, safflower, sunflower, and corn oils, as well as in tofu, nuts and seeds. The American Heart Association recommends eating omega-3 containing fish twice a week and eating your fats from polyunsaturated sources such as nuts, seeds and vegetable oils.
Replacing saturated and trans fatty acids with omega-3 and omega-6 fatty acids may reduce cardiovascular risks, according to previous research.
In the Circulation study led by Hannia Campos, Ph.D., intake of omega-3 from vegetable oils was associated with a 59 percent reduction in heart attack risk. Researchers studied 1,819 residents of Costa Rica who had survived a first heart attack and compared them to a similar group who had not had a heart attack. Participants completed a food and alcohol frequency questionnaire and researchers analyzed body fat samples to determine their alpha-linolenic acid content.
Compared to those with the least amount of alpha-linolenic acid in their body fat samples, those with the highest levels had a 59 percent lower heart attack risk – “a large and significant reduction.”
“Alpha-linolenic acid was associated with a very strong protective effect, and the relationship quickly reached a plateau with most of the effect achieved after just a small intake,” said Campos, senior lecturer in the nutrition department at Harvard School of Public Health in Boston, Mass.
These data suggest that the amount of dietary alpha-linolenic acid required to produce this relationship in this population study corresponded to two teaspoons of soybean oil or canola oil, half a teaspoon of flaxseed oil or six to 10 walnut halves.
If confirmed by further research, it might someday be possible to reduce the prevalence of cardiovascular disease by adding a little of this essential fatty acid to the diet in the many countries where intake of fish containing long-chain omega-3 fatty acids, and vegetable oils containing alpha-linolenic acid is low, as it is in Costa Rica, Campos added.
Compared to the United States, consumption of vegetable oils containing omega-3 and fish is very low in Costa Rica. Residents there also tend to eat tropical white fish, which is much lower in long-chain n-3 fatty acids than the cold-water species such as salmon and mackerel that are commonly eaten in North America, she added.
Fortunately, since the 1980s, the Costa Rican population has decreased consumption of palm oil, a vegetable oil that lacks alpha-linolenic acid and is high in saturated fatty acids. They’ve also increased consumption of other vegetable oils – especially soybean oil – that are rich in alpha-linolenic acid, she said.