More and more researchers have realized that the warnings against saturated fat has no scientific support whatsoever, but there are exceptions. Unfortunately some of them are those, who write the Dietary Guidelines for Americans. In the most recent “Presidential-Advisory” they continue to mislead. Here come the worst examples.
´The scientific rationale for decreasing saturated fat in the diet has been and remains based on well-established effects of saturated fat to raise low-density lipoprotein (LDL) cholesterol, a leading cause of atherosclerosis.´
The fact is that there is a total lack of “scientific rationale” that a high intake of saturated fat raises LDL-cholesterol (the “bad” cholesterol). The most striking observation is that although the Masai people probably eat more saturated fat than any other population in the world, their cholesterol is the lowest ever measured in healthy people. There is no evidence either that a high LDL-cholesterol is the cause of atherosclerosis. I have documented that already 15 years ago in Quarterly Journal of Medicine
´Reducing saturated fat and replacing it with polyunsaturated fat in randomized controlled trials has reduced the incidence of CVD. (By polyunsaturated fat they refer to the omega-6-type; present in large amounts in corn oil, soybean oil and sunflower oil).
According to the author, the strongest evidence for that is the following dietary trials.
The Dayton trial. In that trial the control group ate a standard US diet rich in saturate fat whereas the treatment group had exchanged most of it with polyunsaturated soybean oil. Seven years later a slightly smaller number of those who had eaten the soybean diet had died from a heart attack, but the lower number was balanced by a higher number of cancer deaths. Moreover, although blood cholesterol had been lowered in the treatment group, there was no difference between the degree of atherosclerosis in the two groups.
There are at least two explanations to the high cancer mortality: A high intake of omega-6 polyunsaturated fat increases the risk. Together with five colleagues I have documented that in a paper in Mayo Proceedings I have also commented our paper in a short video
The second reason is that LDL, the molecule that transport the “bad” cholesterol in the blood, protects against cancer. Please read our paper.
Another soybean trial. In the 1960s Professor Jeremy Morris and his coworkers in London performed a similar trial including about four hundred middle-aged men with heart disease. But although blood cholesterol had decreased considerably in the treatment group four years later, the number of deaths from heart disease was 25 in each group.
The Oslo trial. Morris and his coauthors compared their result with a similar but unblinded experiment erformed by Paul Leren, a Norwegian researcher from Oslo. They concluded that, even if Dr. Leren had been more successful, the results of the two trials taken together showed that it was not possible to prevent heart attacks by eating more polyunsaturated fat.
The Finnish Mental Hospital Study. About 700 middle-aged male patients were studied at two mental hospitals. At one of them the patients were given a diet low in saturated fat and cholesterol and high in polyunsaturated fat; at the other one they ate the usual hospital diet. Six years later the diets were reversed and the trial continued for another six years. During the trial some of the patients dropped out, and after the first six years the oldest patients in both groups were exchanged with younger patients. In total, less than a third of the patients completed all of this twelve-year long trial.
To distribute the risk factors evenly between the two groups is of course impossible with such a design. Consequently, there were considerably more smokers, more with high blood pressure, and more on drugs in the control groups.
During both periods, there were fewer people in the diet group who died from a heart attack and fewer, who had other heart problems. However, with one exception, the differences were not statistically significant. And how could they know whether the number of heart attacks in the second period was a consequence of the diet the patients had eaten during the previous six years, or whether it was the result of their present diet?
This trial included female patients as well. In that part of the trial there was no benefit at all, although the cholesterol was reduced more. In the report, published four years later the authors admitted that although the results of this trial do not permit firm conclusions, they support the idea that also among female populations the serum-cholesterol-lowering diet exerts a preventive effect on CHD (!).
Do these trials really. prove that saturated fat is bad? Or that polyunsaturated fat is beneficial?
You can read more about the scandalous ways we have been misled by the American “authorities” in my books. I have made my first and most detailed one, (The Cholesterol Myths) for free. You can also buy a Kindle version or a used paperback for less than two dollars on Amazon.