Posted by: Joseph Dixon | July 28, 2014

Science: Unintended Consequences; Ancel Keys, Cholesterol, and the Transition to an Obese Society; Part XXIII, The Genius of Ancel Keys; What We Know About the Mediterranean Diet Today?

The Genius of Ancel Keys

If you read How to Eat Well and Stay Well the Mediterranean Way, published in 1975 and a New York Times Best Seller, you will recognize that Dr. Ancel Keys and Margaret Keys wrote an expansive review of diet and health that quite frankly cannot be surpassed by later books.   The vast amount of information in the book is staggering, and the recipes are real and every one of them was tested by the Keys family in their own kitchen.

The misinformation concerning Dr. Keys and his views on nutrition and health that are promulgated by some media personalities today is hard to explain. One wonders whether they have taken the time to read Dr. Keys’ books, including Seven Countries and the three cookbooks he and Margaret Keys wrote.

Dr. Keys spent most of his career studying nutrition and health.  And during a very long career, he made many discoveries, including these major accomplishments that had a great impact on the American people:

1. He formulated ready to eat meals (called K-rations) for the American armed forces during World War II.  These turned out to be a technical success and are immortalized in hundreds of movies and books about World War II.

2. He led a major study during World War II on starvation that provided important information on how to treat starved individuals

3. He conceived and implemented the Seven Countries study and identified important dietary factors that protected against coronary heart disease.

But in my opinion, the true genius of Dr. Keys was displayed when he and Margaret Keys wrote the 470 page cookbook, How to Eat Well and Stay Well the Mediterranean Way.   This book clearly explained the effects of diet on health and disease, and then they went on to show how to prepare healthy Mediterranean meals through the tested recipes in the book.  It was their attempt to disseminate their knowledge directly to the American public.

However, the problem in all this was that, although the book was on the New York Times Best Sellers list, the message did not get out to everyone.  And when the book went out of print, it was no longer available to provide guidance to Americans.

Quite honestly, I never heard of How to Eat Well and Stay Well the Mediterranean Way before I started to write about Ancel Keys. In fact, as I discussed earlier, it was difficult to find the book.  And when I read it, I was absolutely amazed at the vast amount of information that it conveyed. The most surprising observations in the entire book were that Dr. Keys stated conclusively that cholesterol intake and total fat intake were not important factors in the development of coronary heart disease.  On the contrary, it was clearly written that the type of dietary fat was the most important factor in the development of CHD.  This conclusion came from the observation that although the total fat kcal consumed on Crete was very high, there was very little coronary heart disease on the island. Dr. Keys scoured the island and could not find any patients with CHD in hospitals or being treated by doctors. This was especially important in convincing Dr. Keys that total fat was not the main culprit in CHD. How to Eat Well and Stay Well the Mediterranean Way was published in 1975 and Seven Countries was published in 1980, and, unfortunately, there was very little overlap in the background material that was presented in each book.

This may have been a mistake, because anyone who did not read How to Eat Well and Stay Well the Mediterranean Way because it was a cookbook, missed out on a wealth of information that it conveyed.  But some how the messages that Dr. Keys and Margaret wrote about were short lived, and because of this, some of the conclusions reached by Dr. Keys were needlessly debated by researchers in the cardiovascular field for many years afterward.

But the news about the Mediterranean diet is being spread by a whole new crop of researchers and physicians.  Even recently, a study on the Mediterranean diet that supported the observations of Dr. Keys was published in 2013.  This study on the protective effects of the Mediterranean diet on CHD was conducted by Dr. Ramon Estruch of the University of Barcelona, and was contributed to by other researchers from around Spain. It was a dietary intervention trial that was designed to have three groups, a control group that was instructed on how to eat a conventional low fat diet, and two groups that were instructed on how to eat a Mediterranean diet, with increased olive oil intake in one group and increased intake of a mixture of nuts in the the other group. When the study was published in the New England Journal of Medicine in April 2013, it was hailed by experts as a breakthrough and a successful study based on its experimental design.

The most important observation made in the study was that even when participants (with no cardiovascular disease at enrollment) were recruited quite late in life (men – 55 to 80 years of age; and women – 60 to 80 years of age), a traditional Mediterranean diet with either ample intake of olive oil or ample intake of nuts was protective (a relative risk reduction of approximately 30%) against acute myocardial infarction, stroke, or death from cardiovascular causes versus the conventional low fat diet was consumed by the control group.

But there was something missing in the discussion section of the Estruch study, and this was the acknowledgment that the results largely supported the observations that Dr. Keys and his colleagues made in the Seven Countries study, and which Dr. Keys reported on in numerous scientific articles and in his two books, How to Eat Well and Stay Well the Mediterranean Way (1975) and Seven Countries (1980).

However, the editors of the New England Journal of Medicine asked Dr. Sarah Tracy to write an editorial to connect the current paper to earlier work by Dr. Keys and others.

Sarah W. Tracy, Ph.D. Something New under the Sun? The Mediterranean Diet and Cardiovascular Health N Engl J Med 368;14 p1274, April 4, 2013

Dr. Tracy wrote, “The first epidemiologic data supporting the Mediterranean diet came from the Seven Countries Study (SCS), a prospective investigation of diet and other cardiovascular-disease risk factors in 16 cohorts totaling nearly 13,000 men in the United States, Italy, Greece, Yugoslavia, Finland, the Netherlands, and Japan, which began in 1958…..The PREDIMED results would come as little surprise to the man behind the SCS, American physiologist and epidemiologist Ancel Keys, who advanced the low-fat diet and the low-saturated fat Mediterranean diet for the primary and secondary prevention of heart disease. Keys “discovered” the Mediterranean diet’s health benefits in the early 1950s, when visiting the region as a medical scientist concerned about the widely reported increase in heart attacks in the United States.”

In my mind, the Estruch study was an important study because it was carefully designed and strictly carried out under difficult, modern-day circumstances.  The most amazing outcome of the study was that the protective effects of the Mediterranean diet were observed in such an older population after only approximately five years of implementation. In fact, the study was stopped after a median follow-up of 4.8 years because the results were so persuasive, and the authors thought it was not ethical to continue the control population, which had higher rates of cardiovascular disease, on the conventional low fat diet.

Interestingly, there was one major difference between the results observed in Dr. Estruch’s study compared to the earlier results observed by Dr. Keys. This was that in the Estruch study, there were no differences in the rates of total deaths from all causes between the populations consuming the Mediterranean diet and the Control population that was consuming a standard low fat diet (Death from any cause 0.82 (0.64–1.07); 0.97 (0.74–1.26); 1.00 (control); p values were 0.15 and 0.82).  In contrast, at the time of Ancel Keys’ study, there were in fact lower total death rates (from all causes) in populations who consumed a Mediterranean diet compared to the participants in the U.S.A. and northern Europe, who consumed a classic “Western” style diet (See figures below). The differences in this important outcome were probably due to the fact that at the time of Keys’ investigations, the populations had been on the Mediterranean diet for most of their lives and they had received more comprehensive protective effects.  Also, the populations in other regions were consuming a higher fat diet.

In 2010 a meta analysis involving a total of more than 2 million subjects investigated the role of the Mediterranean diet in enhancing heath showed that that a 2-point increase in adherence to the Mediterranean diet was associated with a 8% reduction of death from all causes, a 10% reduction in incidence of cardio- and cerebrovascular diseases, a 6% reduction in the incidence of neoplastic diseases, and a 13% reduction in the incidence of neurodegenerative diseases. At first reading these reductions do not seem that significant, but one has to remember that people in many Mediterranean areas are subject to factors that promote a more “Western” lifestyle.

When discussing the utility of the Mediterranean diet today, the most important question would be the one that Dr. Ancel Keys would ask first, Is the Mediterranean diet that is being proposed today the same Mediterranean diet that he studied in the 1950s, when the coronary heart disease rates were extremely low to non-existent?  One problem with more modern studies of the health promoting effects of the Mediterranean diet are that the participants are greatly affected and influenced by the Western lifestyle.  However, the Estruch’s study and the 2010 meta analysis show that the positive effects of the Mediterranean diet can still be observed today.

Therefore, a general conclusion is that populations that consume a Mediterranean diet for their entire lives, not only exhibit lower rates of cardiovascular disease, but they also live a longer life, too, compared to populations eating a “Western” style diet.

Deaths fr All Causes 1967 Ancel Keys

Deaths fr CHD 1967 Ancel Keys

 


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