To understand if Modern Science influences Mediterranean Diet we can read an article from Michel de Lorgeril (cardiologist and nutritionist at the French National Centre for Scientific Research and the School of Medicine at Grenoble University, France). In the 1990s he proposed a theory to explain the French paradox (low mortality rate from cardiac disease in France compared with UK and USA despite similar risk profiles), and his research group demonstrated that the plant omega-3 fatty acid (alpha-linolenic acid) is cardioprotective. Michel de Lorgeril was the principal investigator on the landmark Lyon Diet Heart Study, the first clinical trial to demonstrate the beneficial effects of the Mediterranean diet in the prevention of ischemic heart disease.
After years of biological and medical research, it is definitely possible to look at the Mediterranean diet as a robust and complex scientific concept. It can be used by any practitioner, provided it is adapted to each specific geographic area and population, and called the modernized Mediterranean diet. The next paragraphs will try to explain the shift from the empiric description of the traditional dietary habits of various Mediterranean populations to modern scientific medicine.
One good example is the dietary fat issue. It cannot be summarized with a single statement about olive oil. Briefly, Mediterranean people use several types of fats, from both plant and animal (including marine) sources. Many different fatty acids make up these fats.
Table 2 shows how to compare the modernized Mediterranean diet with a Western-type diet – grossly defined as the dietary habits of the US and North European (Finland, the Netherlands) populations investigated in the Seven Countries Study. It is important to differentiate oleic acid (the main monounsaturated fatty acid) provided by olive oil and the same chemical provided by animal fat. Oleic acid is indeed one of the main fatty acids of beef and pork fat. When the relations between the intake of oleic acid and any health item are analyzed within a Western cohort, investigators mainly analyze the relations with beef and pork consumption. When they do the same within a Mediterranean cohort, they analyze the relations with olive oil and the results are totally different. This may explain why certain (Western) experts refuse to acknowledge any health benefit from consuming olive oil, as if olive oil and oleic acid are the same things.
On the other hand, while the modernized Mediterranean diet is not a vegetarian diet, it is definitely a plant-based diet. It is, therefore, crucial to identify the main sources of the essential omega-3 and omega-6 polyunsaturated fatty acids. Since olive oil is poor in both omega-6 and omega-3 fatty acids, what are the true sources of omega-3 and omega-6 fatty acids in either the traditional or the modernized Mediterranean diet?
Along the same line, it is crucial to differentiate the main sources of the specific omega-3 fatty acids – those provided by plants and those provided by marine or terrestrial animals – and also the main sources of omega-6 fatty acids from either plants or animals
Finally, in the contemporary world where industrial foods are consumed by more and more people, it would be a mistake to still think that most saturated fats come from animal foods. Actually, saturated fatty acids also come from plants, such as the palm oil and cocoa butter incorporated in industrial foods. In the same way, it is essential to differentiate the (toxic) trans fatty acids produced by the industrial hydrogenation process and the (healthy) trans fatty acids naturally produced by ruminants and found in the dairy products typical of the Mediterranean diet.
Finally, it is noteworthy that wheat, both whole and refined, is a major ingredient of the Mediterranean diet, mainly under the form of bread, but also of other typical Mediterranean diet foods, such as pasta and couscous. The physicians and nutritionists who are aware of the basic principles of the modernized Mediterranean diet recommend eating complex carbohydrates and whole grains, in particular bread and other wheat-based foods. However, the last decades have seen great changes in the prevalence and clinical presentation of two diseases linked to wheat: the celiac gluten-induced enteropathy and non-celiac gluten sensitivity. These changes have taken place as new wheat hybrids were introduced into human foods. This is definitely a critical medical and environmental issue, which needs to be appropriately managed by physicians when their patients report new gastrointestinal or non-gastrointestinal symptoms after adhering to the modernized Mediterranean diet. The worst thing to do would be to deny the reality of these symptoms. There are alternatives to gluten-rich grains, and physicians and nutritionists should be careful to select such alternatives so as to respect the basic principles of the modernized Mediterranean diet. Thus, the gluten/wheat issue illustrates how a dietary pattern is not a static thing, but rather an ongoing change.