Forget what you heard about bad fats and heart disease and go indulge in that burger and fries combo you've been craving for lunch. New research reveals that being "good" by substituting saturated fats with vegetable oil doesn't actually do any good for your heart, and may actually increase your risk of dying from cardiovascular complications.
It's true that replacing saturated fats with vegetable oils lowers blood cholesterol, but new research from the National Institutes of Health (NIH) and the University of North Carolina revealed that substituting saturated fats with vegetables oils rich in linoleic acid, a polyunsaturated omega-6 fatty acid, doesn't lower the risk of developing heart disease.
Lead researcher Christopher Ramsden and his colleagues said the latest findings go against the traditionally held assumption that vegetable oil containing high levels of linoleic acid can reduce cardiovascular conditions by cutting cholesterol levels.
Ramsden and his team noticed that previous studies supporting the "diet-heart hypothesis" never casually demonstrated in randomized controlled trials the heart benefits of vegetable oils rich in linoleic acid.
For the latest study, researchers looked at data from a previous study called the Minnesota Coronary Experiment, which involved following 9,423 participants for up to four and a half years. After analyzing links between participant diet, heart disease risk and blood cholesterol levels, researchers found that participants assigned to a diet enriched with linoleic acid had significantly lower cholesterol levels. However, lower cholesterol levels did not help improve participant survival and was actually linked to higher risk of death.
Researchers said the latest study matches findings from their previous study that explained data from the Sydney Diet Heart Study, which revealed that people who replaced saturated fat with vegetable oil rich in linoleic acid actually had a significantly higher risk of dying from coronary heart disease.
Researchers said that current studies "do not provide support for the central diet-heart tenet that the serum cholesterol lowering effects of replacing saturated fat with linoleic acid translate to reduced risks of coronary heart disease and death," according to a journal release.
They noted that the recent revaluation of findings from the unpublished Minnesota Coronary Experiment "add to growing evidence that incomplete publication has contributed to overestimation of the benefits of replacing saturated fat with vegetable oils rich in linoleic acid."
"The benefits of choosing polyunsaturated fat over saturated fat seem a little less certain than we thought," wrote Lennert Veerman, senior lecturer at the University of Queensland, in an accompanying editorial. "While we wait for further clarification, we should continue to eat (and to advise others to eat) more fish, fruits, vegetables and whole grains. We should avoid salt, sugar, industrial trans fats and avoid over eating."
The findings were published in the journal BMJ.
