Health Effects of Mediterranean Diet

Table of Contents:

• Cardiovascular diseases
• Diabetes
• Cancer
• Weight loss in obesity
• Cognitive ability
• Major depressive disorder
• Gluten
• Ageing
• Dietary components

The Mediterranean diet draws inspiration from the dietary practices of Italy and Greece during the 1960s. Key features of this diet include a high intake of olive oil, legumes, unprocessed grains, fruits, and vegetables, along with moderate to high fish consumption. It also involves moderate levels of dairy intake, primarily through cheese and yogurt, as well as moderate wine drinking, and low consumption of meats other than fish. Olive oil, in particular, has been researched for its potential health benefits, including lowering the risk of chronic diseases and reducing overall mortality.

The Mediterranean Diet ranked #1 in Best Diets Overall. 41 diets were evaluated with input from a panel of health experts.

A review from 2017 identified that following a Mediterranean diet can reduce the risk of cardiovascular diseases, overall cancer rates, neurodegenerative diseases, diabetes, and premature mortality. Research in 2018 indicated that adhering to the Mediterranean diet could enhance overall health by lowering the risk of non-communicable diseases, decreasing overall living expenses, and reducing national healthcare costs. Additionally, a 2016 review found that the weight loss achieved with the Mediterranean diet was comparable to that of other diets.

The 2015-2020 national guidelines in the US introduced a “Healthy Mediterranean-Style Eating Pattern,” based on the traditional Mediterranean diet and its beneficial health effects. This pattern was adapted from the “Healthy U.S.-Style Eating Pattern” and modified to include more fruits and seafood while reducing dairy content.

Cardiovascular diseases

The Mediterranean diet is recognized as one of the dietary patterns that could potentially reduce the risk of cardiovascular diseases. A 2013 Cochrane review found only limited evidence supporting the Mediterranean diet’s beneficial impact on cardiovascular risk factors. Additionally, a 2013 meta-analysis, which also reviewed diets like vegan, vegetarian, low-glycemic index, low-carbohydrate, high-fiber, and high-protein, concluded that Mediterranean, low-carbohydrate, low-glycemic index, and high-protein diets effectively improve markers of cardiovascular disease and diabetes risk. However, the evidence for vegetarian diets affecting glycemic control and lipid levels without weight loss was limited. Subsequent reviews from early 2016 expressed concerns about the quality of earlier research and called for more standardized studies, noting that evidence supporting the Mediterranean diet’s role in preventing vascular disease was inconsistent and highly variable. Reviews from 2016-17 similarly noted the Mediterranean diet’s potential to improve cardiovascular risk factors, including lowering the risk of hypertension and other cardiovascular conditions.

The Mediterranean diet is characterized by low levels of saturated fat and high levels of monounsaturated fat and dietary fiber. A key component is olive oil, rich in monounsaturated fats like oleic acid, which is currently being studied for its potential health benefits. The European Food Safety Authority has endorsed health claims for olive oil, recognizing its polyphenols for protecting against oxidation of blood lipids and its role in maintaining normal LDL-cholesterol levels by substituting saturated fats with oleic acid, as per EU Commission Regulation (EU) 432/2012 issued on May 16, 2012. A 2014 meta-analysis found that increased olive oil consumption correlates with lower risks of all-cause mortality, cardiovascular events, and strokes. In contrast, monounsaturated fats from both animal and plant sources did not show significant effects. The American Heart Association promotes the Mediterranean diet as a beneficial dietary pattern for reducing the risk of cardiovascular diseases.

Diabetes

In 2014, two meta-analyses revealed that adopting a Mediterranean diet could lower the risk of type 2 diabetes, a finding echoed by a 2017 review. Further endorsements came from the American Diabetes Association and a 2019 review, both supporting the Mediterranean diet as a beneficial dietary pattern that could potentially reduce diabetes risk.

Cancer

A 2008 meta-analysis indicated that adherence to the Mediterranean diet reduced the risk of cancer mortality by 6%. A subsequent review in 2014 also linked following this diet closely with lower cancer death rates. However, a 2017 review observed a reduced cancer rate associated with the diet, though the evidence supporting this finding was considered weak.

Weight loss in obesity

A 2019 review explored the Mediterranean diet as a dietary strategy that could assist obese individuals in reducing and enhancing the nutritional quality of their food consumption, potentially leading to weight loss.

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

There is a link between following the Mediterranean diet and a reduced risk of depression. However, the studies establishing these links are observational and do not confirm causation.

Gluten

The growing prevalence of gluten-related disorders may be influenced by the rising popularity of the Mediterranean diet, which typically incorporates gluten-containing products such as pasta and bread.

Ageing

Greater adherence to the Mediterranean diet may be linked to longer telomeres, according to some evidence.

Dietary components

The Mediterranean Diet Pyramid outlines the eating habits typical of this diet.

Further information: Mediterranean Cuisine

The “Mediterranean diets” vary across different countries and even among communities within the Mediterranean basin, reflecting ethnic, cultural, economic, and religious differences. The “Mediterranean diet” as identified by dietitians usually comprises components that are not necessarily common to diets found in the Mediterranean basin:

High intakes of olive oil (as the principal source of fat), vegetables (including leafy green vegetables, onions, garlic, tomatoes and peppers), fresh fruits (consumed as desserts or snacks), cereals (mostly whole grains), nuts and legumes.
Moderate intakes of fish and other seafood, poultry, eggs, dairy products (principally cheese and yogurt) and red wine.
Low intakes of red meat, processed meat, refined carbohydrates and sweets.
These pro­por­tions are some­times rep­re­sented in the Mediter­ranean Diet Pyra­mid. In a diet with roughly this com­po­si­tion, the fat con­tent ac­counts for 25% to 35% of the total in­take of calo­ries, while the amount of sat­u­rated fat is, at most, 8% of the calo­rie content.

In con­trast to the di­etary rec­om­men­da­tion, olive oil is not the sta­ple fat in much of the Mediter­ranean basin: 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 (samna) are tra­di­tional sta­ple fats.