The anti-inflammatory effects of a Mediterranean diet: a review

To present the Mediterranean diet (MD) pyramid: a lifestyle for today. A new graphic representation has been conceived as a simplified main frame to be adapted to the different nutritional and socio-economic contexts of the Mediterranean region. This review gathers updated recommendations considering the lifestyle, dietary, sociocultural, environmental and health challenges that the current Mediterranean populations are facing. Mediterranean region and its populations. Many innovations have arisen since previous graphical representations of the MD. First, the concept of composition of the 'main meals' is introduced to reinforce the plant-based core of the dietary pattern. Second, frugality and moderation is emphasised because of the major public health challenge of obesity. Third, qualitative cultural and lifestyle elements are taken into account, such as conviviality, culinary activities, physical activity and adequate rest, along with proportion and frequency recommendations of food consumption. These innovations are made without omitting other items associated with the production, selection, processing and consumption of foods, such as seasonality, biodiversity, and traditional, local and eco-friendly products. Adopting a healthy lifestyle and preserving cultural elements should be considered in order to acquire all the benefits from the MD and preserve this cultural heritage. Considering the acknowledgment of the MD as an Intangible Cultural Heritage of Humanity by UNESCO (2010), and taking into account its contribution to health and general well-being, we hope to contribute to a much better adherence to this healthy dietary pattern and its way of life with this new graphic representation.

Research has shown that a greater adherence to the Mediterranean diet is associated with a reduced risk of major chronic disease. However, the existing literature leads to debate for different issues, such as the measurement of the adherence to the Mediterranean diet, the use of a wide variety of dietary indices with various food components and the large heterogeneity across the studies. In order to summarise the evidence and evaluate the validity of the association between the adherence to the Mediterranean diet and multiple health outcomes, an umbrella review of the evidence across meta-analyses of observational studies and randomised clinical trials (RCTs) was performed. Thirteen meta-analyses of observational studies and 16 meta-analyses of RCTs investigating the association between the adherence to the Mediterranean diet and 37 different health outcomes, for a total population of over than 12 800 000 subjects, were identified. A robust evidence, supported by a P-value<0.001, a large simple size, and not a considerable heterogeneity between studies, for a greater adherence to the Mediterranean diet and a reduced the risk of overall mortality, cardiovascular diseases, coronary heart disease, myocardial infarction, overall cancer incidence, neurodegenerative diseases and diabetes was found. For most of the site-specific cancers, as well as for inflammatory and metabolic parameters, the evidence was only suggestive or weak and further studies are needed to draw firmer conclusions. No evidence, on the other hand, was reported for bladder, endometrial and ovarian cancers, as well as for LDL (low density lipoprotein)-cholesterol levels.