What is the Mediterranean diet?

The Mediterranean diet is an eating model based on the dietary patterns of countries surrounding the Mediterranean Sea including Crete, Greece, Southern Italy, Spain, France, Lebanon, Morocco, Portugal, Syria, Tunisia, and Turkey.^1,2 First described by Ancel Keys in his Seven Countries Study, the Mediterranean diet refers to eating patterns that developed in olive-growing areas of the Mediterranean region before and during the 1960s.^3-5 Its key components are its high monounsaturated/saturated fat ratio and high intake of plant-based foods. The Mediterranean diet is an eating pattern characterized by high consumption of vegetables, legumes, and cereals, low to moderate consumption of fish, dairy, and poultry, and low consumption of red meat.² Another defining feature is that olive oil is the primary source of fat. Wine is often a component of the diet, consumed in low to moderate amounts with meals.

The 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease specifically mentions the Mediterranean diet as a heart-healthy eating pattern.⁶ Numerous studies on the Mediterranean diet have been performed and require that the authors explicitly create criteria for adherence and offer more specific descriptions of the diet.^1,7-9 The landmark study,^7,10 Primary Prevention of Cardiovascular Disease with a Mediterranean Diet, defined a Mediterranean diet by the following rules:

1. use of olive oil for cooking and dressing dishes
2. vegetables ≥2 daily servings with at least one of them as fresh vegetables in a salad, not including side dishes
3. fresh fruits ≥2-3 daily servings (including natural juices)
4. legumes ≥3 weekly servings
5. fish or seafood ≥3 weekly servings with at least one serving of fatty fish
6. nuts or seeds ≥1 weekly serving
7. eat white meats (poultry without skin or rabbit) instead of red meats or processed meats (burgers, sausages)
8. cook regularly (at least twice a week) with tomato, garlic, and onion and serve vegetables, pasta, rice, and other dishes with tomato, garlic, and onion

Another cohort study defined the diet more loosely by identifying eight core components:¹¹

• high monounsaturated to saturated fat ratio
• moderate alcohol consumption
• high legume consumption
• high cereal (including bread and potatoes) consumption
• high fruit consumption
• high vegetable consumption
• low meat consumption
• low dairy-products consumption

Although there are minor variations in specific assessment criteria for the conducted studies, clearly the current definition of the Mediterranean diet has not changed much since its original identification in the 1960s.

Alcohol Consumption Guidelines

Although alcohol is mentioned as part of the traditional Mediterranean diet, people should still be counseled to drink in moderation. The Dietary Guidelines for Americans 2020-2025¹² states that if alcohol is consumed, it should be in moderation—up to one drink per day for women and up to two drinks per day for men—and only by adults of legal drinking age. For those who choose to drink, moderate alcohol consumption is recommended.

^References

1. Rees K, Takeda A, Martin N, et al. Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2019; 3: Cd009825.
2. Willett WC, Sacks F, Trichopoulou A, et al. Mediterranean diet pyramid: a cultural model for healthy eating. Am J Clin Nutr 1995; 61 (6 Suppl): 1402S-1406S.
3. Kromhout D, Keys A, Aravanis C, et al. Food consumption patterns in the 1960s in seven countries. Am J Clin Nutr 1989; 49 (5): 889-894.
4. Martinez-Gonzalez MA, Sanchez-Villegas A. The emerging role of Mediterranean diets in cardiovascular epidemiology: monounsaturated fats, olive oil, red wine or the whole pattern? Eur J Epidemiol 2004; 19 (1): 9-13.
5. Keys A. Mediterranean diet and public health: personal reflections. Am J Clin Nutr 1995; 61 (6 Suppl): 1321s-1323s.
6. Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 2019; 140 (11): e596-e646.
7. Estruch R, Ros E, Salas-Salvado J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013; 368 (14): 1279-1290.
8. Trichopoulou A, Costacou T, Bamia C, et al. Adherence to a Mediterranean diet and survival in a Greek population. N Engl J Med 2003; 348 (26): 2599-2608.
9. de Lorgeril M, Salen P, Martin J-L, et al. Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction. Circulation 1999; 99 (6): 779.
10. Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med 2018; 378 (25): e34.
11. Trichopoulou A, Kouris-Blazos A, Wahlqvist ML, et al. Diet and overall survival in elderly people. BMJ 1995; 311 (7018): 1457.
12. Dietary Guidelines for Americans, 2020-2025. 9 ed: U.S. Department of Health and Human Services and U.S. Department of Agriculture; December 2020.