Posted by: Joseph Dixon | May 18, 2014

Science: Unintended Consequences; Ancel Keys, Cholesterol, and the Transition to an Obese Society; Part VII, Ancel Keys’ Career, Part 3: After The Seven Countries Study

After the the Seven Countries study, Ancel Keys had accumulated three very large and significant accomplishments that highlight a remarkable scientific career. These accomplishments were:

  1. Formulating ready to eat meals (called K-rations) for the American armed forces during World War II
  2. Studying starvation with the purpose of learning the best procedures for treating starved individuals
  3. Conceiving and implementing the Seven Countries study that pointed to diet as being an important factor in the development of coronary heart disease (CHD) disease.

In the early 1950s Ancel Keys visited Rome to chair a conference on nutrition for the Food and Agriculture Organization. He heard from Professor Gino Bergami of the University of Naples that men in Naples, Italy were relatively free of CHD. He later visited the region, and established an office and lab, and learned that the men of Naples did, in fact, have less CHD than the men he studied in Minnesota. After observing similar protection against CHD in Madrid, Spain, Dr. Keys developed the hypothesis that it was the diet of these men that protected them from CHD. His later studies, including the Seven Countries study, convinced him that the Mediterranean diet was an important factor in maintaining health. With this knowledge, Dr. Keys and his wife, Margaret, a biochemist, wrote two very popular cook books that would help people eat healthy. These books were Eat Well and Stay Well (1959), and Eat Well and Stay Well the Mediterranean Way (1975). Both books were featured on the New York Times bestseller list. They wrote a third book, “The Benevolent Bean,” and it was also successful.

Interestingly, the success of these books allowed Dr. Keys and his wife to move to the town of Pollica, south of Naples, Italy, to live during their retirement and eat a Mediterranean diet up close and personal all year long.

The cook books that Ancel and Margaret Keys wrote were another major accomplishment In Dr. Keys’ career, because through these books millions of people improved their health by eating a Mediterranean Diet.

In 1995 Dr. Keys wrote an article where he related his thoughts about the Mediterranean diet in a special issue of the American Journal of Clinical Nutrition.  He defined the Mediterranean diet and emphasized the importance of different kinds of leaves in the diet, including “many kinds of lettuce, spinach, Swiss chard, purslane, and plants I cannot identify with an English name such as lettuga, barbabietole, scarola, and rape.” Dr. Keys noted (written in the 1990s) that the Mediterranean diet was changing in many regions such that more meat and milk was being consumed. After these observations, Dr. Keys started a series of clinical studies in Minnesota that studied how different fats affected blood cholesterol concentrations and these studies were published during the 1960s. Later when Ancel and Margaret traveled, they noted that Italian restaurants were steering father away from the Mediterranean diet they had first experienced in the 1950s.

In the last portion of his article in the AJCN, Dr. Keys was ahead of his time when suggested that healthy eating should be taught to school children. This is a suggestion that nutritionists are recommending today to battle the “Obesity Epidemic.” Certainly, the cookbooks he and his wife wrote disseminated the news about a healthy diet to millions of people throughout the world.

Keys A.  Mediterranean diet and public health: personal reflections.  Am J Clin Nutr. 1995 Jun;61(6 Suppl):1321S-1323S.

http://ajcn.nutrition.org.proxy.libraries.rutgers.edu/content/61/6/1321S.full.pdf+html

Ancel Keys followed the participants in the Seven Countries study for several 5 year follow-ups until he retired from the University of Minnesota in 1972. After retiring, Dr. Keys wrote his famous book, “Seven Countries,” which was published in 1980 by Harvard University Press.

In 1999, the 25 year follow-up of the Seven Countries study was published.

Alessandro Menotti, DaanKromhout, Henry Blackburn, FlaminioFidanza, RatkoBuzina & AulikkiNissinens for the Seven Countries Study Research Group. Food intake patterns and 25-year mortality from coronary heart disease: Cross-cultural correlations in the Seven Countries Study.  European Journal of Epidemiology 15: 507-515, 1999

http://www.jstor.org.proxy.libraries.rutgers.edu/stable/view/3581928

The 25-year CHD death rate in the men who were enrolled in the Seven Countries study was, as in the previous updates, highest in East Finland and lowest in Crete, Greece. The next highest death rates were in West Finland; Zutphen, The Netherlands; and the fourth highest was in the US. The next lowest death rates were the two cohorts from Japan. The full table is shown below.

25 year death rates from Seven Countries

The results from the analysis concerning food intake was succinctly described in the discussion of the paper:

“In fact, food patterns associated with high CHD mortality rates were characterized by high consumption of butter, dairy products and other animal products usually rich in saturated fatty acids and cholesterol. Food patterns associated with low or relatively low mortality rates from CHD were those characterized by high consumption of cereals, legumes, vegetable products, fish, oils and wine.“

The apparent negative effects of butter and dairy fats on CHD observed in the 25-year follow-up study are very similar to those presented in the Connor study discussed in the previous chapter.

The 40-year follow-up to the Seven Countries Study was published in 2007 and it is quite amazing that the participants in this study were in the age range 80 to 99 years old. Because the men were getting so old, they were starting to die of diseases associated with extreme aging. This is exemplified in the table of death rates shown below, where the total death rates from the cohorts were approaching the maximal rate. However, when the CHD data from the entire 40 years of the study were analyzed together (See figure 2 below), some interesting patterns were observed for some of the study cohorts. Serbia and Greece had upswings in their CHD death rates that mirrored the observations of Ancel and Margaret Keys that some countries were turning away from the Mediterranean diet because of an increase in their socio-economic status and a merging of rural and urban areas in some of the sub-industrialized countries. Finland and the USA tended to have lower rates further into the study as programs to lower fat intake took effect. The CHD rate in Japan remained consistently low. The 40 year follow-up accentuated the concept that changing the diet could both lower and increase CHD death rates depending upon the direction of the changes in the diet.

Alessandro Menotti, Mariapaola Lanti, Daan Kromhout, Henry Blackburn, Aulikki Nissinen, Anastasios Dontas, Antony Kafatos, Srecko Nedeljkovic, Hisashi Adachi. Forty-year coronary mortality trends and changes in major risk factors in the first 10 years of follow-up in the seven countries study. Eur J Epidemiol (2007) 22:747–754.

http://download.springer.com/static/pdf/384/art%253A10.1007%252Fs10654-007-9176-4.pdf?auth66=1400549883_b64e2b72f547ac24c85e486da66a812e&ext=.pdf

Table 1 - 40 yr CHD death rates

Change in CHD death rates over 40 yrs

 


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