Saturated fats are often pegged as a main culprit behind heart disease, but a new study suggests that might not be the case.
Researchers reviewed 72 different studies on more than 600,000 people from around the globe, and found little evidence to support medical guidelines that recommend people limit their consumption of saturated fats in order to prevent heart disease.
"These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines," study author Dr. Rajiv Chowdhury, a public health researcher at the University of Cambridge in the U.K., said in a statement. "With so many affected by this illness, it is critical to have appropriate prevention guidelines which are informed by the best available scientific evidence."
Interestingly, the study found saturated dairy fats, specifically margaric acid, significantly reduced the risk of heart disease. They did find "weak" associations between two specific types of saturated fats -- ones found in palm oils and animal fats -- and an increased risk of heart disease, but not enough to support the current dietary recommendations.
Heart disease is the number one killer in the United States and worldwide.
The American Heart Association has said eating foods that are high in saturated fats raise levels of cholesterol in the blood, which could clog arteries and in turn raise risk for heart disease and stroke. The fats are found typically in meat and dairy products, but also in many baked goods and fried foods.
The AHA recommends limiting the amount of saturated fats in a diet to no more than 16 grams per day for a person eating the standard 2,000 calories per day. Instead, the organization suggests using monounsaturated (found in vegetable oils) or polyunsaturated fats, the latter including omega-6 and omega-3 fatty acids, which can reduce cholesterol levels in blood and lower heart disease risk, says AHA.
But the new study also found insufficient evidence that those "better" fats reduced heart disease risk.
They did find some limited evidence that some chains of omega-3's and 6's might reduce heart risks, but not enough to support high consumption of them.
The study was published March 18 in the Annals of Internal Medicine.
Experts said the new research raised questions, but should not change previous recommendations.
The American Heart Association wrote in a blog post on its website that it has concerns "that the study's conclusion could be deceptive for some people as they decide what to put on their plates."
"The study published Monday doesn't change the American Heart Association recommendation of a diet that's rich in fruits and vegetables, whole grains, nuts, fish and unsaturated fats," said the AHA.
Registered dietician Dana White, an assistant clinical professor at Quinnipiac University in Conn., told CBS News in an email that there have been studies suggesting saturated fat is less devastating to heart health than previously thought, but there is still a substantial amount of research supporting the idea that a diet high in butter and fatty meats can be "detrimental."
"At this point I am not ready to tell patients and students to start increasing the amount of saturated fat in their diets," she said.
Dr. Christopher Ochner, an assistant professor of pediatrics, adolescent medicine and psychiatry at the Icahn School of Medicine at Mount Sinai, said this is the first convincing evidence he has seen that suggests saturated fats may be "unfairly vilified" in terms of heart disease risk.
"To be clear, this by no means indicates that saturated fats are safe or that intake of saturated fats does not need to be monitored," he said in an email.
The research does raise questions that need to be experimented further, to determine whether dietary recommendations need to be reconfigured, Ochner added.
"At this point, individuals should still make sure fats and sugar are consumed in moderation, maintain a healthy body weight, remain physically active, not smoke and have regular medical examinations in order to minimize the risk of cardiovascular disease," he said.