Is coconut oil a metabolism-boosting superfood or an artery-clogging threat to heart health?

That question has fueled a raging debate for many years, and it was reignited in mid-June when the American Heart Association (AHA) issued an advisory reiterating its longstanding recommendation to avoid saturated fats. Attention quickly focused on coconut oil, which has become trendy in natural health circles despite its high saturated fat content.

Proponents of coconut oil say its medium-chain triglycerides are quickly burned for energy, increasing metabolism. Coconut oil fats are also said to be good for the brain, which is made mostly of fat, and help regulate blood sugar and, ironically, cholesterol levels.

But the AHA advisory contends that all saturated fats raise risk of cardiovascular disease.

“Taking into consideration the totality of the scientific evidence…we conclude strongly that lowering intake of saturated fat and replacing it with unsaturated fats, especially polyunsaturated fats, will lower the incidence of cardiovascular disease,” states the advisory.

The AHA researchers specifically advise against using coconut oil, which they note is 82 percent saturated fat and raises “bad” LDL cholesterol levels, “a cause of atherosclerosis.”

But many other scientific reviews in recent years — including one meta-analysis encompassing nearly 350,000 people followed for as long as 23 years — found no link between saturated fat and heart disease.

“Those reviews were much more limited because they didn’t take into consideration what the substitution [for saturated fats in the diet] was,” explains Dr. Alice Lichtenstein, co-author of the AHA advisory. “The better reviews that looked at replacing saturated fat with either carbohydrates or mono- or polyunsaturated fats, show clear differences.”

Many natural health practitioners take exception to the AHA conclusions, including integrative cardiologist Dr. Jack Wolfson. He contends that AHA researchers cherry-picked data from decades-old studies, and that branding all LDL as harmful is outdated science.

“Total LDL numbers are a very poor prognosticator of heart disease,” says Wolfson, a doctor of osteopathy and board-certified cardiologist based in Phoenix, Ariz. “What’s more relevant is LDL particle size and numbers. Small, dense particles are bad for the heart, but studies show that large fluffy particles, like those promoted by coconut oil, cause no harm.”

But Lichtenstein, director of the Cardiovascular Nutrition Laboratory at Tuft University’s Human Nutrition Center on Aging, dismisses the LDL particle size factor, saying, “There’s much more written on the Internet about that than data to support it.”

Wolfson further questions AHA recommendations to use “highly processed” vegetable oils, saying their omega-6 fatty acids can contribute to systematic inflammation. In an AHA newsletter, the advisory’s lead author, Dr. Frank Sacks, suggests that people forsake butter and coconut oil for cooking and use canola, corn, soybean, and extra virgin olive oil instead.

“There’s nothing wrong with deep frying as long as you deep fry in a nice unsaturated vegetable oil,” Sacks adds.

That suggestion may send shudders through natural health practitioners, who widely contend that vegetable oils break down into harmful compounds under high heat.

“Coconut oil has a high smoke point, which makes it more stable for cooking,” explains Wolfson. “Unsaturated vegetable oils oxidize through the cooking process and cause oxidative stress and inflammation in the body.”

Lichtenstein once again cites a lack of data on the adverse effect of cooking with vegetable oils, telling Newsmax Health, “It’s not a concern.”

Wolfson also points out that the evolving science of heart disease seems to be shifting away from cholesterol and more toward inflammation as the primary cause.

“The risk of a cardiovascular event – heart attack, stroke and dying -- is much higher when you have inflammation,” says Wolfson, author of “The Paleo Cardiologist: The Natural Way to Heart Health” and advocate of eating diets similar to our caveman ancestors.

“Coconut oil doesn’t cause inflammation. Sugar, artificial ingredients, pesticide residue in food…these are the types of things that cause inflammation.”

He emphasizes that it’s important to eat healthy saturated fats that are organic and, if animal-based, come from grass-fed pasture-grazers. Wolfson adds that he has history on his side in the debate over whether they are healthy or harmful.

“Our ancestors ate saturated fats for millions of years,” he tells Newsmax Health. “Why would evolution make it plug up our pipes and kill us? People in the South Pacific have diets that are more than 50 percent coconut-based, and they have virtually no heart disease. If we were all on a deserted island eating coconuts, fish and vegetables, and getting plenty of sunshine and sleep, heart disease would be a non-issue.”