Sunflower, grapeseed and corn oil may actually be better for our health than olive oil, a study has found
For years, we've been told to guzzle olive oil to protect our hearts.
Now, however, a study has found we should be cooking with sunflower, grapeseed or corn oil instead.
People with higher levels of linoleic acid in their blood, which is prevalent in these oils, had leaner bodies and less fat around their vital organs, researchers found.
Having a leaner body lengthens a person's lifespan as it allows them to remain active for longer, researchers said.
Those with higher blood levels of linoleic acid also lowered their risk of type 2 diabetes and heart disease, they added.
The team compare linoleic acid found in oils from nuts and seeds to oleic acid, which is found in olive oils, as the latter has been long recommended for heart health.
Linoleic acid is a polyunsaturated omega-6 fatty acid abundant in many nuts and fatty seeds, including oils such as grapeseed, safflower, poppyseed, sunflower, hemp, corn, sesame and walnut.
Oleic acid is a monounsaturated omega-9 fatty acid found in olive, canola, peanut oil, macadamia and sunflower oil.
Both polyunsaturated and monounsaturated fats are known as 'essential' fatty acids as the body cannot produce them itself, therefore they must be consumed as part of our diet.
They are considered 'healthy fats' when compared with the trans fats found in vegetable oils, as these increase harmful levels of cholesterol in the body.
The study by The Ohio State University compared the effects of these two types of polyunsaturated and monounsaturated fats as well as another healthy type - the long-chain omega-3 fatty acids found in fish such as salmon and tuna.
It found inflammation decreased as levels of all these fatty acids rose in the blood.
But higher levels of oleic acid or long-chain omega-3s did not appear to be linked to a person's body fat levels.
It also did not reduce the risk of type 2 diabetes, despite longstanding recommendations that people eat more olive oil and fatty fish - a finding the researchers said were extremely surprising.
Lead author Professor Martha Belury, of The Ohio State University, said: 'It really kind of popped out and surprised us.'
Previous research has found just a teaspoon and a half a day of linoleic acid increased lean body mass and lowered fat around the middle.
The new study was the first to examine the link between levels of linoleic acid in the blood, body fat and other markers of health in people who hadn’t been given supplements or prescriptive diets.
The new finding backs up previous research showing cardiovascular benefits of linoleic acid.
Because of these past studies, the American Heart Association recommended people take in at least 5 to 10 per cent of their energy in the form of omega-6 fatty acids, which includes linoleic acid, in 2009.
However, a shift away from trans fats means many low-cost cooking oils rich in linoleic acid are disappearing from shops.
When linoleic acid is made solid for processed foods, it is more likely to convert to trans fat than its oleic cousin.
Therefore, food manufacturers began to genetically modify oils to make them higher in oleic acid.
Professor Belury said: 'Vegetable oils have changed. They’re no longer high in linoleic acid.'
So oils, notably safflower, sunflower and soybean, now routinely contain less linoleic acid than they did years ago.
For now, grapeseed oil for now remains an excellent source of linoleic acid, and corn oil is also a decent source, Professor Belury said.
The study was published in the journal Molecular Nutrition & Food Research.
People who had high levels of linoleic acid, which is found in sunflower, grapeseed and corn oil, also had leaner bodies and less fat around their vital organs, researchers found (file photo)
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