The Mediterranean Diet (MedDiet) has been utilized for centuries in countries around the Mediterranean basin, such as Crete and Corfu as well as other parts of Greece, Southern Italy, and Spain (1). Over several decades, scientists have been closely studying the health benefits of this eating pattern. In the late 1950s Ancel and Margaret Keys developed the term “Mediterranean Diet” to describe the regional dietary patterns. The diet was not well known until the publication of the Seven Countries Study over fifty years ago. Multiple large observational, epidemiological, and intervention trials have been conducted to ascertain the MedDiet’shealth benefits. The purpose of this article is to explore the dietary components, health benefits, and the associated health-promoting lifestyle.

Dietary Components of the Mediterranean Diet

The MedDiet varies across the region, however some common threads have been identified (1,2):

• Predominance of plant-based foods such as fruits, vegetables, legumes, whole grains, potatoes, nuts and seeds
• Infrequent consumption of red meat (1 – 3 times per month)
• Preferential consumption of chicken, turkey, or rabbit instead of veal, pork, hamburger, or sausage
• Regular consumption of fish or shellfish (> 3 servings a week)
• Regular consumption of small quantities of dairy products, like cheese and yoghurt
• Regular consumption of eggs (as much as 4 per week)
• Infrequent consumption of processed commercial sweets or pastries
• Infrequent consumption of sweetened and/or carbonated beverages
• Use of olive oil as the main source of fat with daily consumption of > 4 tablespoons
• Regular ingestion of moderate amounts of red wine with meals

Health Benefits

The health benefits related to the MedDiet were first identified by the Five Countries Study, which started in 1958 (3). Scientists were astonished to find individuals following a diet with 30 – 40% fat content had a lower incidence of cardiovascular disease than the recommended less than 30% fat in the United States. Consequently, the MedDiet has been studied extensively. In 2010 a systematic review reported 18 studies with a total of 2,190,627 subjects (4). The sample sizes ranged from 161 to 485,044 with a follow-up time of 4 to 20 years. In 2015 another systematic review reported 59 studies conducted from 2008 through 2014 (5). These studies included epidemiological, observational, cohort, and randomized controlled trials. This growing mound of research has consistently found a positive impact of the MedDiet on health benefits such as:

• Longevity
• Cardiovascular disease, including myocardial infarction and stroke
• Various forms of cancer
• Neurodegenerative diseases, like Alzheimer’s and Parkinson’s diseases
• Respiratory conditions, such as asthma control and sleep apnea
• Chronic kidney disease
• Obesity
• Decreased risk of Diabetes Type 2 and Metabolic Syndrome
• Arthritis

No one food or nutrient within the MedDiet has been identified as solely responsible for these health benefits (3, 4). Instead, the advantages are probably the result of synergistic interactions between the major components. The whole diet has anti-inflammatory and anti-oxidant properties (3-9). The monosaturated fatty acids in the olive oil influences fatty acid metabolism decreasing the formation of pro-inflammatory eicosanoids. The whole diet provides a large intake of anti-inflammatory polyphenols. In addition, the plant-based diet offers a high fiber intake.  So, the combined effects are the results of the monosaturated fatty acid, fiber and polyphenol intake.

Health-promoting Lifestyle

As noted in Figure 1, the MedDiet is more than a diet. A health-promoting lifestyle is depicted in the Mediterranean Diet Pyramid including physical activity, adequate rest, conviviality, culinary skills, and socialization (8, 9). Regular physical activity is encouraged as well as rest, such as naps. Convivality suggests the sense of friendliness, affability, and cheerfulness. Meals are typically prepared and eaten in a social setting with family and friends. Consequently, these lifestyle elements must be taken into consideration when assessing the MedDiet’s health benefits.

In conclusion, the MedDiet has a plant based core with an emphasis on fresh fruits, vegetables, and whole grains. Also, the dietary pattern minimizes red meat and sugar intake. Regular consumption of olive oil and wine is included. Health benefits from the whole diet impact a majority of chronic diseases such as cardiovascular and metabolic conditions. The diet has anti-inflammatory and anti-oxidant properties. The MedDiet is not just a list of temporary dietary restrictions. It is a lifestyle.

References:

1. Vasto, S., Barea, A., Rizzo, C., Di Carlo, M., Caruso, C., &Pantopoulos, G. (2014). Mediterranean Diet and longevity: An example of nutraceuticals? Current Vascular Pharmacology, 12, 735-738.
2. Martinez-Gonzalez, M., Salas-Salvado, J., Estruch, R., Corella, D., Fito, M., &Ros, E. (2015). Benefits of the Mediterranean Diet: Insights from the PREDIMED study. Progress in Cardiovascular Diseases, 58, 50-60.
3. Damone, R.B. (2011). Health benefits of the Mediterranean Diet: An east-west approach. Oriental Medicine, 20-24.
4. Sofi, F., Abbate, R., Gensini, G., &Casini, A. (2010). Accruing evidence on the benefits of adherence to the Mediterranean diet on health: An updated systematic review and meta-analysis. American Journal of Clinical Nutrition, 92, 1189-1196.
5. Gotsis, E., Anagnostis, P., Mariolis, A., Vlachou, A., Katsiki, N., &Karagiannis, A. (2015). Health benefits of the Mediterranean diet: An update of research over the last 5 years. Angiology, 66, 304-318.