Coconut Research Center

New Study Proves Saturated Fat DoesNotCause Heart Disease

Saturated fat has proven to be relatively benign while sugar poses a greater risk for heart disease

For many years the prevailing thought among the majority of health care professionals was that saturated fats promoted, if not caused, heart disease. We have been fed this line now for the past five decades. We’ve heard it so many times that we just assume that there is a mountain of evidence to back it up. However, the evidence has been sorely lacking. In fact, many studies have refuted this theory, but since these studies go contrary to the popular medical belief, they are generally ignored and forgotten. Only those studies that seem to support the saturated fat-heart disease hypothesis are given any recognition or publicity. However, a growing body of research challenging the saturated fat-heart disease connection is starting to convince many doctors to reconsider how they look at fats and heart disease.

A new study published this week in the journalAnnals of Internal Medicineshowed beyond a reasonable doubt that saturated fats do not cause heart attacks and other cardiac events. The researchers discovered that saturated fats do not cause heart disease while so-called “healthy” polyunsaturated fats do not prevent cardiovascular problems. In contrast with decades old nutritional advice, researchers at Cambridge University have found that giving up fatty meat, cream, or butter is unlikely to improve health. They are calling for guidelines to be changed to reflect a growing body of evidence suggesting there is no overall association between saturated fat consumption and heart disease.

“My take on this would be that it’s not saturated fat that we should worry about” in our diets, said Dr. Rajiv Chowdhury, the lead author of the new study and a cardiovascular epidemiologist in the department of public health and primary care at Cambridge University.

In the new research, Dr. Chowdhury and his colleagues sought to evaluate the best evidence to date. They conducted a “meta-analysis” of data from 72 studies involving more than 600,000 participants from 18 countries. The scientists also reviewed evidence from 27 randomized controlled trials – the gold standard in scientific research – that assessed whether taking polyunsaturated fat supplements like fish oil promoted heart health. The key finding was that total saturated fat, whether measured in the diet or the bloodstream, showed no association with heart disease. In addition, levels of so-called healthy polyunsaturated fats such as omega-3 and omega-6 had no general effect on heart disease risk. There was no less disease in those eating higher amounts unsaturated fat, including monounsaturated fat like olive oil or polyunsaturated fat like corn oil. Only omega-3 fatty acids found in fish was linked to a lower risk of heart disease. However, popular omega-3 and omega-6 supplements appeared to have no benefit.

The researchers did find a link between trans fats, produced when vegetables oils are hydrogenated. Partially hydrogenated vegetables oils and are commonly found in processed foods. But they found no evidence of dangers from saturated fat, or benefits from other kinds of fats.

The primary reason saturated fat has historically had a bad reputation is that it increases low-density lipoprotein cholesterol, or LDL, the kind that has been assumed to raise the risk for heart attacks. But the relationship between saturated fat and LDL is complex, said Dr. Chowdhury. In addition to raising LDL cholesterol, saturated fat also increases high-density lipoprotein, or HDL, the so-called good cholesterol that has shown to protect against heart disease. And the LDL that it raises is a subtype of big, fluffy particles that are generally benign.

The smallest and densest form of LDL is more dangerous. These particles are easily oxidized and are more likely to set off inflammation and contribute to the buildup of artery-narrowing plaque. An LDL profile that consists mostly of these particles usually coincides with high triglycerides and low levels of HDL, both risk factors for heart attacks and stroke.

The smaller, more artery-clogging particles are increased not by saturated fat, but by sugar, sugary foods, and an excess of carbohydrates, Dr. Chowdhury said. “It’s the high carbohydrate or sugary diet that should be the focus of dietary guidelines,” he said. “If anything is driving your low-density lipoproteins in a more adverse way, it’s carbohydrates.”

While the new research showed no relationship overall between saturated or polyunsaturated fat intake and cardiac events, there are numerous unique fatty acids within these two groups, and there was some indication that they are not all equal.

When the researchers looked at fatty acids in the bloodstream, for example, they found that margaric acid, a saturated fat in milk and dairy products, was associated with lower cardiovascular risk. Two types of omega-3 fatty acids, the polyunsaturated fats found in fish, were also protective. But a number of the omega-6 polyunsaturated fatty acids, commonly found in corn, soybean, and other vegetable oils and processed foods, may pose risks, the findings suggested.

The researchers then looked at data from the randomized trials to see if taking supplements like fish oil produced any cardiovascular benefits. It did not.

But Dr. Chowdhury said there might be a good explanation for this discrepancy. The supplement trials mostly involved people who had pre-existing heart disease or were at high risk of developing it, while the other studies involved generally healthy populations.

So it is possible that the benefits of omega-3 fatty acids lie in preventing heart disease, rather than treating or reversing it. At least two large clinical trials designed to see if this is the case are currently underway.

Despite the clear evidence presented in this and many other studies, it will take a long time before doctors change their way of thinking. Most are so entrenched with the belief that saturated fats are harmful that they will continue to stick with the old beliefs.

Dr. Frank Hu, a professor at the Harvard School of Public Health, who was not involved in the study, said the findings should not be taken as “a green light” to eat more steak, butter, and other foods rich in saturated fat. In other words, we should not abandon old ways simply because new science proves otherwise. In like manner, Bruce Griffin, professor of nutritional metabolism at the University of Surrey, who also was not involved in the study, cautions against taking this study to literally, “To suggest that the theory relating saturated fat to increased total cholesterol is flawed, is nonsense, and contradicts 50 years of evidence based medicine.” What he is inferring is that we should ignore new evidence because it contradicts a generally accepted and loved theory. Note that the saturated fat-heart disease connection is just atheory. After 50 years of research no one has yet to prove it, but many studies have disproven it, including the current study.

Alice H. Lichtenstein, a nutritional biochemist at Tufts University, agreed that “it would be unfortunate if these results were interpreted to suggest that people can go back to eating butter and cheese with abandon.” Dr. Lichtenstein, who also was not involved in the latest study, was the lead author of the American Heart Association’s (AHA) dietary guidelines, which recommend that people restrict saturated fat to as little as 5 percent of their daily calories, or roughly two tablespoons of butter or two ounces of cheddar cheese for the typical person eating about 2,000 calories a day. The heart association states that restricting saturated fat and eating more unsaturated fat, beans and vegetables can protect against heart disease by lowering LDL cholesterol. However, according to this new study Dr. Lichtenstein and the AHA are wrong. Saturated fat increases HDL (the good) cholesterol and the large (benign) LDL. It does not increase the small (harmful) LDL, that’s what sugar does. This is not the first time that the AHA policies have clashed with science. It makes one wonder whose interests the AHA represents—the people, or the pharmaceutical industry who make billions of dollars selling drugs to treat high cholesterol, telling us to avoid saturated fat but eating sugar is okay. The AHA will continue to sell its outdated theory of heart disease and caution against the use of saturated fats despite this and similar studies. Your doctor, unfortunately, will continue to be misled and confused about the issue.■