Scientists and dieticians consistently rank The Modern Mediterranean Diet (MED diet) as the diet most recommended. But often people don't know what the MED diet is. This post will define the Med diet.
Critics of the Med Diet
Critics argue that there is no uniform MED diet. They make these assertions based on one of these three arguments:
Heart disease and Diet
Ancel Keys is the scientist most responsible for not only the Med diet but the relationship of heart disease to diet. In the 1950's, heart disease was thought to be a disease of aging, and smoking but not diet or lifestyle.
In the 1950's, much like today, heart disease was the number one cause of death among of middle aged executives. While there was a clear association between smoking and heart disease, there were far more deaths than could be explained from smoking. Then an Italian scientist told Dr. Keys about the low incidence of cardiovascular deaths of men in Naples.
Keys confirmed this claim when he took a sabbatical in Oxford in 1952. Keys found there was a difference of heart disease between the poor and the executives of Italy. He developed the hypothesis that diet might explain difference between the two groups. To confirm this Keys, and his wife, then traveled throughout Europe catalog different diets and rates of heart disease.
In 1955 Keys presented his data to the World Health Organization, concluding that diet played a significant role in heart disease. Many members of the WHO mocked his "diet-heart theory." Keys then organized the seven countries study (click here).
The seven countries study was an observational study looking at biomarkers, lifestyles and their relationship to heart disease. Those countries were Greece, Italy, former Yugoslavia, Finland, The Netherlands, Japan, and the United States. The cohorts were chosen because of diverse diets, lifestyle, and risk factors. Dietary and lifestyle influence on cardiovascular disease was unknown at the time.
The seven country study was to answer the question about dietary influence and heart disease.
Low-carb bloggers accuse the seven country study of leaving out France. They cite the French Paradox, that the French eat a diet high in saturated fat but have a low incidence of heart disease.
However, France was not left out of the study. French investigators were present at the original pilot study in Nicotera Italy, but ultimately decided not to participate in the study. France was recovering from World War 2 and simply didn't have the resources to commit to such a study.
In fact, The French Paradox was "coined" in the 1980s, over twenty years after the start of the seven country study. The investigators didn't have access to that data, or the term. Low-carb bloggers didn't read the seven country study or the French paradox.
Two factors explain the French Paradox.
The high fat diet was not widely adopted by the French prior to the mid 1970's. It takes time for a habit to have an effect on cardiovascular disease. For example, one doesn't develop heart disease after the first cigarette. The primary French diet in the 1950's through 70's was a Mediterranean Diet. Thus, the effect of the high fat diet would not be evident for twenty plus years after it was adopted.
The second explanation is that French physicians consistently underreported heart disease. Of note, Wine consumption has been the most studied aspect of the French Paradox. Red wine sales increased dramatically after the airing of the "French Paradox" on Sixty Minutes. Wine is an important component of the Med diet.
From 1958 to 1970 over 12,000 men were tracked for diet, weight, smoking, physical activity, vital signs, cholesterol, and lung capacity. During that time there were about 2300 deaths, 27% from heart disease. Different countries had different rates of deaths from heart disease: USA 50%, Northern Europe 40%, Southern Europe 17%, Japan 5%. The dietary pattern that was identified in this study became the basis of what Keys would call The Mediterranean Diet. Key's book became a bestseller, describing not only the first version of the Mediterranean Diet, but providing healthy recipes for a country trying to fight the number one killer. Keys even wrote a best selling cookbook with his wife touting the benefit of the diet.
Adopting the Mediterranean Diet
Keys died shortly before his 101'st birthday. There are a number of great articles written about Keys, but the obituary here is one of the finest.
The first scoring system for the Med diet was proposed in 1995 (here). Other studies began to arise to determine the Med diet for cancer, autoimmune diseases, longevity, dementia, and other disease states.
One of the more famous was a meta analysis of twelve studies looking at longevity. Greater adherence in this scale also showed lower incidence of Parkinson's disease, Alzheimer's disease as well as cardiovascular mortality.
This scale gave points for increased consumption of vegetables, fruits, legumes, cereals, fish, and moderate red wine consumption. While those who had "above the median" of red and processed meats and dairy were given zero points. Ultimately this was refined further with the use of monounsaturated fatty acids (olive oil) as the primary fat (60% or greater).
Trichopoulou, and her colleagues began the European Prospective Investigation into Cancer and Nutrition (EPIC) study in 1994 after the pilot study in 1991. The study enrolled more than 521,000 participants from 23 centers in 10 western European countries, detailing diet, lifestyle, medical history, and vital signs.
They used a validated food frequency questionnaire of over 150 foods commonly consumed in Greece. "For this analysis, we focused on nine nutritional variables: vegetables, legumes, fruits and nuts, dairy products, cereals, meat and meat products, fish and seafood, monounsaturated to saturated lipid ratio, and ethanol." (11).
A two point increase in the Mediterranean diet score led to a decrease in mortality of 14%.
Diet pyramids were common in the 1990's . One of the more famous was from Oldways where they developed a pyramid in 1994 to describe the Mediterranean Diet. (12). This pyramid was based primarily on the diet from the Island of Crete and southern Italy from the 1960's.
Diet pyramids are of little use in scientific studies, as they don't quantify the amounts of foods consumed. Some argue that diet pyramids are a useful way to display the data.
The Lyon heart study was a randomized secondary trial testing the Mediterranean Diet against the French Prudent diet. After 46 months there were 1.24 per one hundred patients who had either a cardiac death or nonfatal infarction. This compared to 4.07 per one hundred who had the standard cardiac diet. They also noted that most patients, after a few years, were still following the Mediterranean Diet, showing that adoption and compliance was not difficult.
The Mediterranean Diet is useful not only for disease, but for weight management. The latest drugs for obesity are GLP-1 agonists (Wegovy, Ozempic) there is a clear benefit from polyunsaturated fatty acids (PUFA) and raising GLP-1. While obese patients have lower GLP-1 response to glucose than non-obese, the PUFAs in the Mediterranean diet provide an increase in GLP-1.
Further the polyphenolic compounds of the Mediterranean Diet provide another benefit. People with the highest intake of polyphenols (especially the flavonoids) were associated with...
