What is the Mediterranean Diet?

30 Nov

What is the Mediterranean Diet?

Many things may spring to mind when thinking about the Mediterranean- warm blue seas, hot summers, sunny skies, rugged hilly landscapes, fresh seafood, and lots of olive oil. It is a geographical region of lands surrounding the Mediterranean sea and its cuisine is one of the most appreciated aspects of this region. However, it should not be confused with the Mediterranean diet, which is an extensively researched, popular diet containing key components with many potential health benefits. This includes reducing risks of all-cause mortality, heart disease, metabolic diseases, and promoting longevity, common in countries such as Italy, Cyprus and Spain (1).

Let’s take a look at what the Mediterranean diet is and how the different components of the diet may benefit health.

What is the Mediterranean diet?

Originally formulated in the 1960s, the Mediterranean diet was inspired by the eating habits of those living near the Mediterranean sea in countries such as Greece, Spain, Italy and France (2). The Mediterranean diet is typically characterised by a (3,4):

  • high intake of vegetables, fruits, olive oil, legumes, nuts, seeds and whole unprocessed grains
  • moderate intake of fish, poultry and wine during meals
  • low intake of dairy products, red meat and sweets.

This diet is low in saturated and trans-fats, and is rich in monounsaturated and polyunsaturated fats, fibre, vitamins, and plant-derived compounds such as polyphenols (5). The schematic diagram below may provide a useful visual representation of what the diet consists of (6):

This diet is different from the eating patterns commonly seen in ‘western’ diets which include increased intakes of refined sugar, grains and highly processed foods. It is an extensively described and evaluated dietary pattern in scientific literature (7), and adherence to this diet has shown to be protective against many different diseases (8). There are unique dietary components to this diet which may be beneficial for health. The Mediterranean diet also emphasises the implementation of healthy lifestyle factors and the preservation of cultural elements, as they may contribute to the diet’s beneficial effects (9). The following foods and lifestyle factors are prioritised in a Mediterranean diet (6,9,10):

Daily Food Intake:

  • A variety of mainly plant-based food sources (vegetables, fruits, legumes and preferably wholegrain carbohydrates), herbs and spices
  • Healthy fats (through foods such as olive oil, nuts, seeds and oily fish)
  • A daily intake of water as the main beverage, and a moderate intake of red wine with meals

Weekly Food Intake:

  • Fish as the preferred animal protein source at least twice weekly
  • Other protein sources such as eggs, poultry and dairy products a few times weekly
  • Red meat consumption limited to less than twice weekly

Lifestyle Factors:

  • Eating in moderation
  • Socialising during meals
  • Cooking
  • Adequate rest
  • Regular physical activity
  • Prioritising seasonal, local and minimally processed foods

There are no specific portion sizes, but some guidance may be found in the pyramid (6,10). Quantities of foods making up an individual’s meal may vary, depending on the individual (10). Consulting a professional such as a nutritional therapist may be helpful to implement a specific healthy diet and lifestyle factors.

Health Benefits of the Mediterranean diet:

Some of the main mechanisms of key nutrition components in the diet include reduced inflammation, reduced blood lipids (fats), blood glucose (sugar) control, a reduction in cardiovascular risk factors, reduced oxidative stress (an imbalance between free radicals and antioxidants in the body) through its antioxidant properties, and an improvement in metabolic markers (such as insulin resistance) (5,11). Studies have shown numerous potential health benefits through these mechanisms including:

  • Reduced risks of developing type 2 diabetes mellitus (8,12,13)
  • Reduced central obesity and other obesity-related chronic disease risks (13)
  • Reduced risks of cardiovascular disease (8,14)
  • Protection against development of dementia (11)
  • Preservation of cognitive and brain function (11)
  • Supporting weight loss maintenance (15)
  • Higher adherence to the diet is associated with lower risks of cancer mortality (16)

Key dietary components may be underpinning these mechanisms and contributing to these potential health benefits.

Key Dietary Components of the Mediterranean Diet:

Olive Oil: Olive oil should be the main source of dietary fat in a Mediterranean diet. Its high content of monounsaturated fatty acids, antioxidant compounds and polyphenols (organic plant compounds) may be responsible for the positive effects it may exert on the body by reducing inflammation, reducing oxidative stress, supporting the cardiovascular system (heart health), improving insulin sensitivity and it may also support cognitive health (9,11).

Fish: Oily fish including salmon, sardines, tuna and mackerel are rich in omega-3 fatty acids (11). Omega-3 fatty acids are known to have anti-inflammatory effects in the body, and may also support cardiovascular and cognitive function (7,11). Omega-3 fatty acids include both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and these fatty acids cannot be produced efficiently within the body (11). It is therefore important that these nutrients are regularly consumed as part of an individual’s diet.

Fruits and vegetables: An increased intake of fruits and vegetables has been associated with higher blood nutrient levels, reduced oxidative stress, and improved cognitive function (11). Vegetables such as fresh green salad leaves, tomatoes, aubergine, cucumber and cabbage, along with many others, contain important natural compounds such as polyphenols and flavonoids (7). Fruits such as citrus fruits, berries and pomegranates also contain these natural compounds (7). Food sources high in polyphenols may have anti-inflammatory effects in the body as they may inhibit various pro-inflammatory markers (5), and they may also lower fasting blood glucose levels, increase antioxidant potential, and support endothelial function (7), which is important for heart health. Flavonoids may also provide cardio- and neuroprotective properties (11). In addition to these compounds, fruits and vegetables also contain dietary fibre. Dietary fibre may contribute to improvements in insulin sensitivity and managing blood glucose levels (7). Dietary fibre may also positively influence the gut microbiota (community of gut bacteria) by stimulating the production of short-chain fatty acids (SCFAs) (17). SCFAs may help regulate glucose and fat metabolism in the body (17). Increased fruit and vegetable intake has also been associated with reduced risks of all-cause mortality, type 2 diabetes and adiposity, amongst other things (7).

Nuts: Nuts are a good source of monounsaturated and polyunsaturated fatty acids, protein, natural compounds such as phenols and flavonoids, fibre, vitamins and minerals (7). Nuts such as pistachios, almonds, walnuts and hazelnuts may be commonly consumed in a Mediterranean diet (7). The fatty acids contained in nuts may have anti-inflammatory effects and support lipid metabolism and brain function (11).

Red wine: Red wine consumed with meals, in moderation, may be an important component of the Mediterranean diet. Red wine contains resveratrol which is a plant compound with antioxidant properties. Resveratrol has shown to exert cardioprotective, antiviral, antioxidant, anti-inflammatory and neuroprotective effects in the body (18).

The Mediterranean diet is more than just a diet, it is also a lifestyle model. As discussed, various food components in this diet may be beneficial to health, but at a more holistic level, lifestyle factors such as exercise, community living and rest may also play a role in supporting health along with diet. The extensive research conducted around this diet has allowed us to identify many potential foods and lifestyle principles which may support optimal health. Adoption of a Mediterranean diet may include making dietary and lifestyle changes which are long-term and sustainable. It provides a loose guide for a healthful diet which is rich in nutrients such as healthy fats, polyphenols, dietary fibre and protein. Adherence to this diet has shown to be supportive of health in many ways and protective against several chronic diseases.

Claudia Ripamonti is completing her final year in Personalised Nutrition (BSc). She has an interest in gut health and is passionate about supporting others in their health journeys. To see more of her posts and healthy food creations, she can be found on Instagram as @happy_whole_healthy.

References:

  1. World Economic Forum, 2020. This is where people live the longest in the EU. [online] Available at: < https://www.weforum.org/agenda/2020/12/longest-life-expectancy-europe/> [Accessed: 28 November 2022]
  2. Trichopoulou, A., Martínez-González, M.A., Tong, T.Y., Forouhi, N.G., Khandelwal, S., Prabhakaran, D., Mozaffarian, D. and de Lorgeril, M., 2014. Definitions and potential health benefits of the Mediterranean diet: views from experts around the world. BMC medicine, 12(1), pp.1-16.
  3. Willett, W.C., Sacks, F., Trichopoulou, A., Drescher, G., Ferro-Luzzi, A., Helsing, E. and Trichopoulos, D., 1995. Mediterranean diet pyramid: a cultural model for healthy eating. The American journal of clinical nutrition, 61(6), pp.1402S-1406S.
  4. D’Innocenzo, S., Biagi, C. and Lanari, M., 2019. Obesity and the Mediterranean diet: a review of evidence of the role and sustainability of the Mediterranean diet. Nutrients, 11(6), p.1306.
  5. Sood, S., Feehan, J., Itsiopoulos, C., Wilson, K., Plebanski, M., Scott, D., Hebert, J.R., Shivappa, N., Mousa, A., George, E.S. and Courten, B.D., 2022. Higher Adherence to a Mediterranean Diet Is Associated with Improved Insulin Sensitivity and Selected Markers of Inflammation in Individuals Who Are Overweight and Obese without Diabetes. Nutrients, 14(20), p.4437.
  6. Fundación Dieta Mediterránea, 2010. Mediterranean Diet Pyramid: a lifestyle for today. [pdf] Available at: <http://www.mediterradiet.org/dietamed/piramide_INGLES.pdf> [Accessed: 21 November 2022].
  7. Schwingshackl, L., Morze, J. and Hoffmann, G., 2020. Mediterranean diet and health status: Active ingredients and pharmacological mechanisms. British journal of pharmacology, 177(6), pp.1241-1257.
  8. Muscogiuri, G., Verde, L., Sulu, C., Katsiki, N., Hassapidou, M., Frias-Toral, E., Cucalón, G., Pazderska, A., Yumuk, V.D., Colao, A. and Barrea, L., 2022. Mediterranean Diet and Obesity-related Disorders: What is the Evidence?. Current Obesity Reports, pp.1-18.
  9. Bach-Faig, A., Berry, E.M., Lairon, D., Reguant, J., Trichopoulou, A., Dernini, S., Medina, F.X., Battino, M., Belahsen, R., Miranda, G. and Serra-Majem, L., 2011. Mediterranean diet pyramid today. Science and cultural updates. Public health nutrition, 14(12A), pp.2274-2284.
  10. Harvard T.H Chan, 2018. Diet Review: Mediterranean Diet. [online] Available at: <https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/mediterranean-diet/#:~:text=The%20Mediterranean%20diet%20is%20a,protein%20being%20fish%20and%20seafood> [Accessed: 23 November 2022].
  11. Gauci, S., Young, L.M., Macpherson, H., White, D.J., Benson, S., Pipingas, A. and Scholey, A., 2021. Mediterranean diet and its components: potential to optimize cognition across the lifespan. In Nutraceuticals in Brain Health and Beyond (pp. 293-306). Academic Press.
  12. Ahmad, S., Demler, O.V., Sun, Q., Moorthy, M.V., Li, C., Lee, I.M., Ridker, P.M., Manson, J.E., Hu, F.B., Fall, T. and Chasman, D.I., 2020. Association of the Mediterranean diet with onset of diabetes in the Women’s Health Study. JAMA network open, 3(11), pp.e2025466-e2025466.
  13. Bendall, C.L., Mayr, H.L., Opie, R.S., Bes-Rastrollo, M., Itsiopoulos, C. and Thomas, C.J., 2018. Central obesity and the Mediterranean diet: A systematic review of intervention trials. Critical reviews in food science and nutrition, 58(18), pp.3070-3084.
  14. Estruch, R., Ros, E., Salas-Salvadó, J., Covas, M.I., Corella, D., Arós, F., Gómez-Gracia, E., Ruiz-Gutiérrez, V., Fiol, M., Lapetra, J. and Lamuela-Raventos, R.M., 2018. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. New England journal of medicine, 378(25), p.e34.
  15. Poulimeneas, D., Anastasiou, C.A., Santos, I., Hill, J.O., Panagiotakos, D.B. and Yannakoulia, M., 2020. Exploring the relationship between the Mediterranean diet and weight loss maintenance: The MedWeight study. British Journal of Nutrition, 124(8), pp.874-880.
  16. Schwingshackl, L., Schwedhelm, C., Galbete, C. and Hoffmann, G., 2017. Adherence to Mediterranean diet and risk of cancer: an updated systematic review and meta-analysis. Nutrients, 9(10), p.1063.
  17. Martín-Peláez, S., Fito, M. and Castaner, O., 2020. Mediterranean diet effects on type 2 diabetes prevention, disease progression, and related mechanisms. A review. Nutrients, 12(8), p.2236.
  18. Salehi, B., Mishra, A.P., Nigam, M., Sener, B., Kilic, M., Sharifi-Rad, M., Fokou, P.V.T., Martins, N. and Sharifi-Rad, J., 2018. Resveratrol: A double-edged sword in health benefits. Biomedicines, 6(3), p.91.
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