Mediterranean diet
The Mediterranean diet is a concept first proposed in 1975 by American biologist Ancel Keys and chemist Margaret Keys. It is inspired by the eating habits and traditional foods of Greece, Italy, and the Mediterranean coasts of France and Spain, as observed in the late 1950s to early 1960s. The diet is distinct from Mediterranean cuisine, which encompasses the diverse culinary traditions of Mediterranean countries, and from the Atlantic diet of northwestern Spain and Portugal, albeit with some shared characteristics. The Mediterranean diet is the most well-known and researched dietary pattern in the world.
While based on a specific time and place, the "Mediterranean diet" generically describes an eating pattern that has been refined based on the results of multiple scientific studies. It emphasizes plant-based foods, particularly unprocessed cereals, legumes, vegetables, and fruits; moderate consumption of fish and dairy products ; and low amounts of red meat, refined grains, and sugar. Alcohol intake is limited to wine consumed in low to moderate amounts, usually with meals. Olive oil is the principal source of fat and has been studied as a potential health factor for reducing all-cause mortality and the risk of chronic diseases.
The Mediterranean diet is associated with a reduction in all-cause mortality in observational studies. A 2017 review provided evidence that the Mediterranean diet lowers the risk of heart disease and early death; it may also help with weight loss in obese people. The Mediterranean diet is one of three healthy diets recommended in the 2015–2020 Dietary Guidelines for Americans, along with the DASH diet and vegetarian diet. It is also recognized by the World Health Organization as a healthy eating pattern.
Mediterranean cuisine and its associated traditions and practices were recognized as an Intangible Cultural Heritage of Humanity by UNESCO in 2010 under the name "Mediterranean Diet". The Mediterranean diet is sometimes broadened to include particular lifestyle habits, social behaviors, and cultural values closely associated with certain Mediterranean countries, such as simple but varied cooking methods, communal meals, post-lunch naps, and regular physical activity.
Health effects
Food research
The Mediterranean diet is low in saturated fat with high amounts of monounsaturated fat and dietary fiber. One possible factor is the potential health effects of olive oil in the Mediterranean diet. Olive oil contains monounsaturated fats, most notably oleic acid, which is under clinical research for its potential health benefits. 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 and for the contribution to the maintenance of normal blood LDL-cholesterol levels by replacing saturated fats in the diet with oleic acid. 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.The United States 2015–2020 national guidelines devised a "Healthy Mediterranean-Style Eating Pattern" from the Mediterranean diet patterns and its positive health outcomes. It was designed from the "Healthy U.S.-Style Eating Pattern", but recommends more fruits and seafood, and less dairy. A 2020 review of research on the Mediterranean diet indicated that it may optimize cardiovascular health.
Overall health and disease risk
A 2017 review found evidence that practice of a Mediterranean diet could lead to reduced risk of cardiovascular diseases, overall cancer incidence, neurodegenerative diseases, diabetes, and early death. A 2018 review showed that practice of the Mediterranean diet may improve overall health status, such as reduced risk of non-infectious diseases, may reduce total costs of living, and may reduce costs for national healthcare. A 2016 review found similar weight loss as other diets.Cardiovascular diseases: research through 2017
The Mediterranean diet is included among dietary patterns that may reduce the risk of cardiovascular diseases. A 2013 Cochrane review found limited evidence that a Mediterranean diet favorably affects cardiovascular risk factors. A 2013 meta-analysis 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, while there was limited evidence for an effect of vegetarian diets on glycemic control and lipid levels unrelated to weight loss. A Mediterranean diet was recommended in 2016 as a means of lowering apolipoprotein B.In 2016, the American Heart Association discussed the Mediterranean diet as a healthy dietary pattern that may reduce the risk of cardiovascular diseases.
However, more cautious reviews arose in 2016, raising concerns about the quality of previous systematic reviews examining the impact of a Mediterranean diet on cardiovascular risk factors. These reviews encouraged the need for further standardized research, with one review and meta-analysis concluding that the quantity and quality of the available evidence were highly variable, cautioning that limitations exist about the certainty of possible clinical outcomes from consuming a Mediterranean diet. Other reviews in 2016-17 reached further conclusions about the ability of a Mediterranean diet to improve cardiovascular risk factors, such as lowering the risk for hypertension and other cardiovascular diseases.
Cardiovascular diseases: research since 2019
A 2019 Cochrane review found that uncertainty exists about the effects of a Mediterranean‐style diet on cardiovascular disease occurrence and risk factors in people both with or without extant cardiovascular disease. The review further discussed that research on the diet provided evidence for only modest benefits against cardiovascular disease risk factors, with the research having low to moderate quality.A 2023 review provided evidence for a reduction of mortality and cardiovascular disease risk in women on a Mediterranean-type diet. A 2024 meta-analysis found that adherence to consuming these foods was associated with reduction in cardiovascular disease risk.
Diabetes
In 2014, two meta-analyses found that the Mediterranean diet was associated with a decreased risk of type 2 diabetes, findings similar to those of a 2017 review. The American Diabetes Association and a 2019 review indicated that the Mediterranean diet is a healthy dietary pattern that may reduce the risk of diabetes.Cancer
A meta-analysis in 2008 found that strictly following the Mediterranean diet was correlated with a decreased risk of dying from cancer by 6%. Another 2014 review found that adherence to the Mediterranean diet was associated with a decreased risk of death from cancer. A 2017 review found a decreased rate of cancer, although evidence was weak. An updated review in 2021 found that the Mediterranean diet is associated with a 13% lower risk of cancer mortality in the general population.Weight loss in obesity
Overweight adults who adopt Mediterranean diets may lose weight by consuming fewer calories. A 2019 review found that the Mediterranean diet may help obese people lower the quantity and improve the nutritional quality of food intake, with an overall effect of possibly losing body weight.Cognitive ability
A 2016 systematic review found a relation between greater adherence to a Mediterranean diet and better cognitive performance; it is unclear if the relationship is causal.According to a 2013 systematic review, greater adherence to a Mediterranean diet is correlated with a lower risk of Alzheimer's disease and slower cognitive decline. 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.
Major depressive disorder
studies have found a correlation between adherence to the Mediterranean diet and a lower risk of depression but have not proven that a Mediterranean diet lowers the risk of depression.Gluten
As the Mediterranean diet usually includes products containing gluten, such as pasta and bread, increasing use of the diet may have contributed to the growing rate of gluten-related disorders.Dietary components
There are variations of the "Mediterranean diets" in different countries and among the individual populations of the Mediterranean basin, due to ethnic, cultural, economic and religious diversities. The "Mediterranean diet" as defined by dietitians generally includes the following components, which are not typical of diets in the Mediterranean Basin:- High intakes of olive oil, and a plant-based diet: vegetables, fresh fruits, cereals, nuts, and legumes.
- Moderate intakes of fish and other seafood, poultry, eggs, dairy products, and red wine.
- Low intakes of red meat, processed meat, refined carbohydrates, and sweets.
Some cuisines of the Mediterranean region are not fully consistent with Mediterranean diet guidelines. For instance, olive oil is not the staple fat in the cuisines of all countries which border the Mediterranean: in northern and central Italy, lard and butter are commonly used in cooking, and olive oil is reserved for dressing salads and cooked vegetables; in both North Africa and the Middle East, sheep's tail fat and rendered butter are traditional staple fats.