Mediterranean diet

The Mediterranean diet is a modern nutritional recommendation originally inspired by the dietary patterns of Greece, Southern Italy, and Spain in the 1940s and 1950s.^[1] The principal aspects of this diet include proportionally high consumption of olive oil, legumes, unrefined cereals, fruits, and vegetables, moderate to high consumption of fish, moderate consumption of dairy products (mostly as cheese and yogurt), moderate wine consumption, and low consumption of non-fish meat products.^[2]

There is tentative evidence that the Mediterranean diet lowers the risk of heart disease and early death.^[3][4] Olive oil may be the main health-promoting component of the diet.^[5] There is preliminary evidence that regular consumption of olive oil may lower all-cause mortality and the risk of cancer, cardiovascular disease, neurodegeneration, and several chronic diseases.^[5][6][7][8]

Health effects

A 2016 review found similar weight loss as other diets.^[9]

Dietary factors may be only part of the reason for health benefits gained by certain Mediterranean cultures. Physically active lifestyle, lower body mass index, cessation of smoking and moderate alcohol consumption also may contribute.^[10]

Heart disease

A 2011 systematic review found that a Mediterranean diet appeared to be more effective than a low-fat diet in bringing about long-term changes to cardiovascular risk factors, such as lowering cholesterol level and blood pressure.^[11] A 2013 Cochrane review found limited evidence that a Mediterranean diet favorably affects cardiovascular risk factors.^[3] A meta-analysis in 2013 compared Mediterranean, vegan, vegetarian, low-glycemic index, low-carbohydrate, high-fiber, and high-protein diets with control diets. The research concluded that Mediterranean, low-carbohydrate, low-glycemic index, and high-protein diets are effective in improving markers of risk for cardiovascular disease and diabetes.^[12] However, concerns have been raised about the quality of previously performed systematic reviews and meta-analyses examining the impact of a Mediterranean diet on cardiovascular risk factors.^[13] Newer reviews have reached similar conclusions about the ability of a Mediterranean diet to improve cardiovascular risk factors such as high blood pressure.^[14]

The Mediterranean diet often is cited as beneficial for being low in saturated fat and high in monounsaturated fat and dietary fiber. One of the main explanations is thought to be the health effects of olive oil included in the Mediterranean diet. Olive oil contains monounsaturated fats, most notably oleic acid, which is under clinical research for its potential health benefits.^[6] The European Food Safety Authority Panel on Dietetic Products, Nutrition and Allergies approved health claims on olive oil, for protection by its polyphenols against oxidation of blood lipids^[15] and for the contribution to the maintenance of normal blood LDL-cholesterol levels by replacing saturated fats in the diet with oleic acid^[16] (Commission Regulation (EU) 432/2012 of 16 May 2012).^[17] A 2014 meta-analysis concluded that an elevated consumption of olive oil is associated with reduced risk of all-cause mortality, cardiovascular events and stroke, while monounsaturated fatty acids of mixed animal and plant origin showed no significant effects.^[7]

Diabetes

In 2014, two meta-analyses found that the Mediterranean diet was associated with a decreased risk of type 2 diabetes.^[18][19]

Cancer

A meta-analysis in 2008 found that strictly following the Mediterranean diet reduced the risk of dying from cancer by 6%.^[4]

Another 2014 systematic review and meta-analysis found that adherence to the Mediterranean diet was associated with a decreased risk of death from cancer.^[20] There is preliminary evidence that regular consumption of olive oil may lower the risk of developing cancer.^[8]

Cognitive ability

According to a 2013 systematic review, greater adherence to a Mediterranean diet is associated with a lower risk of Alzheimer's disease and slower cognitive decline.^[21] Another 2013 systematic review reached similar conclusions, and also found a negative association with the risk of progressing from mild cognitive impairment to Alzheimer's, but acknowledged that only a small number of studies had been done on the topic.^[22] The decreased risk has been estimated at 13%.^[4] It may also decrease other neurological disorders such as Parkinson's disease.^[4]

Gluten

As the Mediterranean diet usually includes products containing gluten like pasta and bread, increasing use of the diet may have contributed to the growing rate of gluten-related disorders.^[23][24]

Dietary components

Mediterranean roasted vegetables

Although there are many different “Mediterranean diets” among different countries and populations of the Mediterranean basin, because of ethnical, cultural, economical and religious diversities, the distinct Mediterranean diets generally include the same key components, in addition to regular physical activity:^[25][26][27]

• High intakes of extra virgin olive oil (as the principal source of fat), vegetables (including leafy green vegetables), fresh fruits (consumed as desserts or snacks), cereals (mostly wholegrains), nuts and legumes.
• Moderate intakes of fish (especially marine blue species), seafood, poultry, dairy products (principally cheese and yogurt) and red wine (with the exception of Muslim populations).
• Low intakes of eggs, red meat, processed meat and sweets.

Total fat in this diet is 25% to 35% of calories, with saturated fat at 8% or less of calories.^[27]

In Northern Italy lard and butter are commonly used in cooking, and olive oil is reserved for dressing salads and cooked vegetables.^[28] In both North Africa and the Middle East, sheep's tail fat and rendered butter (samna) are traditional staple fats.^[29]

History

The concept of a Mediterranean diet was developed to reflect "food patterns typical of Crete, much of the rest of Greece, and southern Italy in the early 1960s".^[27] Although it was first publicized in 1975 by the American biologist Ancel Keys and chemist Margaret Keys (his wife and collaborator),^[30] the Mediterranean diet failed to gain widespread recognition until the 1990s. Objective data showing that Mediterranean diet is healthful originated from results of epidemiological studies in Naples and Madrid ^[31] confirmed later by the Seven Countries Study, with first publication in 1970,^[32] and a book-length report in 1980.^[33] The most commonly understood version of the Mediterranean diet was presented, among others, by Walter Willett of Harvard University's School of Public Health from the mid-1990s on.^{[34][35][36][37][38]}

The Mediterranean diet is based on what from the point of view of mainstream nutrition is considered a paradox: although the people living in Mediterranean countries tend to consume relatively high amounts of fat, they have far lower rates of cardiovascular disease than in countries like the United States, where similar levels of fat consumption are found. A parallel phenomenon is known as the French Paradox.^[39]

A diet rich in salads was promoted in England during the early Renaissance period by Giacomo Castelvetro in A Brief Account of the Fruits, Herbs, and Vegetables of Italy.^[40]

In 2013, UNESCO added the Mediterranean diet to the Representative List of the Intangible Cultural Heritage of Humanity of Italy (promoter), Morocco, Spain, Portugal, Greece, Cyprus, and Croatia.^[41][42] It was chosen because "The Mediterranean diet involves a set of skills, knowledge, rituals, symbols and traditions concerning crops, harvesting, fishing, animal husbandry, conservation, processing, cooking, and particularly the sharing and consumption of food." ^[43]

Portugal

When Ancel Keys and his team of researchers studied and characterized the Mediterranean diet and compared it with the eating habits of the US and the most developed countries during that period, some identified it as the "Diet of the Poor". According to the famed Portuguese gastronomist Maria de Lourdes Modesto who met with Keys, Portugal was included in their observations and studies, and Keys considered Portugal had the most pure "Mediterranean" diet. However, Salazar, the dictator of Portugal, did not want the name of Portugal included in the diet of the poor.^[44]

Still today the name of the diet is not consensual among Portuguese gastronomists. After the Mediterranean diet became well-known, some studies evaluated the health benefits of the so-called "Atlantic diet", which is similar to Keys' "Mediterranean" diet, but with more fish, seafood, and fresh greens. Virgílio Gomes, a Portuguese professor and researcher on food history and gastronomy says, Portuguese cuisine is really an "Atlantic cuisine".^[44]

See also

• Cretan diet
• Cuisine of the Mediterranean
• Mediterranean Diet Foundation
• Health effects of wine
• Sustainable diet

References

External links

Media related to Mediterranean Diet at Wikimedia Commons