There are significant differences between the traditional approach and the modern approach to fighting heart disease. Why is that the case?
This post won’t be a comprehensive account of the history of heart disease research. That would be impractical and unnecessary. Instead I’ll relate a couple of stories that show us that the conventional wisdom on cholesterol has been shaped by both dishonest science, and by problems inherent in all sciences.
Much of the information in this post comes from a speech by Dr. Peter Attila, which you can find here.
Ancel Keys was featured on the cover of Time magazine in January 1961.
Keys was hailed for demonstrating the causal link between dietary fat, cholesterol and heart disease. His most famous output is the graph below:
We can see a clear link between dietary fat and deaths due to heart disease. This result was so comprehensive that it helped to shape policy for decades. Unfortunately, there were were actually 22 countries in the original dataset. Keys cherry-picked the most compelling outcomes. This is data mining – one of the most dishonest and pernicious errors in science. When the full 22 country dataset was displayed the results were less convincing:
The USA consumes the same amount of fat as Norway and the Netherlands, yet the rate of heart disease in the USA is almost 4 times higher. Overall there is still a relationship, but it is not so compelling.
Western Electric Company
In 1957 Oglesby Paul began observing 5,400 employees of the Western Electric Company. After four years they compared the individuals with the highest dietary fat intake to those with the lowest (15% in each case). There were 14 deaths from heart disease in the group with the highest fat intake and 16 in the group with the lowest. Based on this result it is difficult to argue that dietary fat is linked to heart disease.
In 1981 the study was revisited. The researchers concluded that the amount of saturated fat in the diet was not associated with increased risk of heart disease. They commented:
“although most attempts to document the relation of dietary cholesterol, saturated fatty acids and polyunsaturated fatty acids to serum cholesterol concentration in persons who are eating freely have been unsuccessful, positive results have been obtained in [four] investigations…Within the context of the total literature, however, the present observations support the conclusion that the [fat] composition of the diet affects the level of serum cholesterol and the long-term risk of death from CHD”
In other words: “we didn’t find anything but we reckon the hypothesis still holds, and our research supports that”. This is obviously a contradiction. The study showed no relation, and could hardly support the prevailing thesis.
This is what the Washington Post had to say:
“The new report strongly reinforces the view that a high-fat, high-cholesterol diet can clog arteries and cause heart disease”
The study showed no relation WHATSOEVER!! Not even correlation, never mind causation.
But worse was to come.
In 1990 the American Heart Association and the National Heart Lung and Blood Institute produced a report call “The Cholesterol Facts” in which they cited the Western Electric dataset as one of the 7 “epidemiological studies showing the link between diet and CHD[that] have produced particularly impressive results” and “showing a correlation between saturated fatty acids and CHD”.
This is the pathetic and deplorable research on which our dietary guidelines are based.
Finally there are inevitable frictions that slow the process of the latest scientific discoveries becoming general knowledge. After a study is complete it can take years to be reviewed and approved for publication. It takes many more years for the study’s insights to become widely disseminated among the academic community. Then it must be added to undergraduate course material for the next crop of GPs (in the case of medical science) to use it as part of their practice.
Moreover, new research that challenges the prevailing wisdom also challenges the researchers and practitioners whose profession is based on that wisdom. These people can be reticent to welcome the new insight. Hence Planck’s aphorism that science advances one funeral at a time.
So even without the lazy, and outright fraudulent actions described above, the general knowledge will always be 20+ years behind the frontier of science.