The Mediterranean diet is the subject of 7,076 scientific studies (and counting). Let’s dig into the research to see if this food approach is as great as the internet makes it sound.

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Written by Emma Loewe: Writer, author, and editor of Cultured. Her writing explores the intersection of nature, climate, and human health. Emma is the author of “Return to Nature” and “The Spirit Almanac.”
Reviewed by Jennie O’Grady: Senior SciComms Specialist at Seed Health

Welcome to Cultured Check, where we put wellness hacks under a microscope to help you decide if they’re worth your time. The internet has a way of stripping health topics of critical nuance. At Cultured, it’s our job to add it back. Join our team of science communicators as we dig up the citations you won’t see on social media, provide context where it’s lacking, and clearly share our findings so you can walk away knowing the whole truth behind the trends. 

Yesterday, I watched a video of a woman chowing down on a tub of butter and a T-bone steak. Between bites, she faced the camera to say something to any vegans who might be watching: their food choices were poisoning them. The comment section was, to put it mildly, heated. The whole thing encapsulated just how dogmatic, extreme, and polarized our nutrition landscape has become. 

Perhaps it’s no surprise that the Mediterranean diet has gained popularity as a kind of safe middle ground. It just snagged the top slot on the U.S. News & World Report Best Diets of the Year list for the seventh year in a row, and social media now houses over 40 million videos of Mediterranean-inspired meals and tips. 

How did this regional way of eating become so globally ubiquitous, and is it actually as great as the internet makes it sound? Join us as we cut into the research on the Mediterranean diet and its impact on gut health, tradition, and culture.

The Claim: “The Mediterranean Diet Is the Top Eating Plan for Overall Health”

There are some discrepancies in how the Mediterranean diet is defined, but it tends to be high in vegetables, fruits, whole grains, herbs, and monounsaturated fats like olive oil.1 It includes some animal protein but is low in sugar, red meat, highly processed foods, and most alcohol (other than red wine). 

The diet is said to mimic traditional foods favored by countries bordering the Mediterranean Sea (though upwards of 20 countries across three continents and 29,000 miles of coastline fit this bill, and they all have their own regional cuisines). 

American researcher Ancel Keys is credited with making the Mediterranean the mecca of “healthy” eating globally.2 From 1958 to 1970, Keys traveled to seven countries—Finland, Holland, Italy, the United States, Greece, Japan, and Yugoslavia—to observe their traditional diets. He monitored ~11,000 people in these countries to determine how their eating habits might impact their cardiovascular disease risk.

You can probably guess the results of his Seven Countries Study: Residents of Italy and Greece seemed to run a lower risk of cardiovascular mortality, and Keys deduced that it was because of their diets (especially the types of fats they ate).3 

American researcher Ancel Keys is credited with making the Mediterranean the mecca of ‘healthy’ eating globally.

Though it was cutting-edge at the time, by today’s standards, Keys’ research was far from perfect. For starters, he only studied men. “In those days, we did not consider involving women because of the great rarity of cardiac events among them, and the invasiveness of our field examinations.” Henry Blackburn, MD, another scientist on the project, writes in a retrospective on the research.4 Blackburn also recalls that the study’s geographical areas and participants were chosen in part “for reasons of convenience.”

Limitations aside, Keys’ research kicked off a wave of interest in the Mediterranean diet and its potential impacts on health and longevity.

The Context: The Best Diet Is What’s Best for Your Microbes

There has been no shortage of research on the benefits of the Mediterranean diet in the decades since—particularly for cardiovascular health.

“No other dietary pattern has undergone such a comprehensive, repeated, and international assessment of its cardiovascular effects…The MedDiet has successfully passed all the needed tests and it approaches the gold standard for cardiovascular health,” reads one review by the American Heart Association.5 Components of the eating plan are also thought to be protective from metabolic syndrome and cancer.6,7

The MedDiet’s impact on these massive diseases can be traced back to a much smaller domain: the gut microbiome. As gastroenterologist and Seed Scientific Board Member Emeran Mayer, MD says, “The best diet is what’s best for your microbes.” The microscopic ecosystem in your gut can influence everything from immune function to mood to metabolism, after all. 

The Mediterranean diet scores high marks for its microbial impact thanks to its fiber, vitamin, and antioxidant content. Here’s why:

  • The Mediterranean diet can be up to twice as high in some forms of fiber as the stereotypical Western diet.8 The MedDiet’s emphasis on whole grains, legumes, vegetables, and fruits gives gut bacteria plenty of complex carbohydrates to feed on. (Learn more about why fiber is such a feast for your microbes here.) In the process of breaking down these plant fibers, bacteria produce short-chain fatty acids (SCFAs) such as butyrate, acetate, and propionate. These byproducts help suppress the growth of pathogenic bacteria in the gut, reduce inflammation, and strengthen the intestinal barrier.9,10 
  • The Mediterranean diet is high in plants and omega-3s that contain antioxidants like vitamins A and C, carotenoids, and glutathione.11 These also have an anti-inflammatory effect and help maintain a strong and protective gut barrier.12 They’ve been shown to combat chronic inflammation in the gut, potentially offering protection from disorders such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS).13
  • Some Mediterranean diet staples, like onions and garlic, are sources of prebiotics. These prebiotic substrates “feed” beneficial bacteria, further promoting the production of gut-strengthening SCFAs and warding off harmful pathogens.14 

The Cultured Check: Food and Culture Are Personal

The verdict is in: The Mediterranean diet is one nutrition approach we can get behind due to its emphasis on fiber, whole foods, and omega-3s. We also appreciate that it isn’t as restrictive as other fad diets that cut out entire food groups your gut bacteria depend on (looking at you, low-FODMAP.) Its emphasis on plants also lowers its associated greenhouse gas emissions.15 

However, as mentioned earlier, there is no one way to eat like you’re in the Mediterranean. Research reflects this: One literature review notes that previous studies on the “Mediterranean diet” have asked participants to eat anywhere from 15.7 to 80 mL/day of olive oil, 5.5 to 60.5 g/day of legumes, and 210 to 682 g/day of vegetables; over a five-fold difference in some cases.1

If you’re interested in trying it out, we recommend streamlining these numbers and aiming to fill your plate with at least 70% plants instead (unless you have a particular deficiency or health condition) for the sake of your microbiome.

These don’t need to be limited to olives, San Marzano tomatoes, or other foods you’d find in the fields of Naples either. Different plants contain unique types of fiber and prebiotics that nourish different species of gut bacteria, so variety is key.16 

While other regional ingredients are not as frequently studied as those from the Mediterranean, that isn’t necessarily a reflection of their nutritional value. Some researchers note that this discrepancy could be the result of racial biases in nutrition research and the glorification of white vs. nonwhite cultural diets.17

So instead of following some “universal” (and let’s face it, whitewashed) version of the Mediterranean diet, allow yourself to make it your own. Apply its emphasis on fiber, whole grains, and healthy fats to your own culture and regional cuisine. 

For maximum microbial benefits, we’d also recommend adding some fermented foods and probiotics to the mix.

Finally, it’s important to remember that diet is about more than nutrition. Positive social interactions, stress-relieving activities, exercise, and time in nature also play important roles in supporting your microbiome. Let’s not forget the origin of the word “diet”: The Greek word diaita, or “way of life.

The Key Insight

The Mediterranean diet has proven benefits for the gut (and beyond), and it’s a refreshingly adaptable nutrition philosophy in an otherwise dogmatic landscape. If you’re looking to use food to feel better in the new year, incorporating more of its staples like fruits, vegetables, legumes, nuts, grains, and omega-3s will likely help. 

That said, the MedDiet as it exists on Instagram and TikTok isn’t right for everyone. Instead of sticking to foods that are native to a particular region of the world, you’re better off working with the ingredients that you have access to and enjoy. Food is synonymous with culture, and a world where everyone eats the same things sounds pretty dreadful. Instead of using food to take a trip to Italy, let’s treat it as a journey to our own backyards.

Citations

  1. Davis, C., Bryan, J., Hodgson, J., & Murphy, K. (2015). Definition of the Mediterranean diet; A literature review. Nutrients, 7(11), 9139–9153. https://doi.org/10.3390/nu7115459
  2. Lăcătușu, C., Grigorescu, E., Floria, M., Onofriescu, A., & Mihai, B. (2019). The Mediterranean diet: From an environment-driven food culture to an emerging medical prescription. International Journal of Environmental Research and Public Health, 16(6), 942. https://doi.org/10.3390/ijerph16060942
  3. Keys, A., Menotti, A., Aravanis, C., Blackburn, H., Djordevič, B. S., Buzina, R., Dontas, A., Fidanza, F., Karvonen, M. J., Kimura, N., Mohaček, I., Nedeljkovič, S., Puddu, V., Punsar, S., Taylor, H. L., Conti, S., Kromhout, D., & Toshima, H. (1984). The seven countries study: 2,289 deaths in 15 years. Preventive Medicine, 13(2), 141–154. https://doi.org/10.1016/0091-7435(84)90047-1
  4. Blackburn, H. (1995). On the Trail of Heart Attacks in Seven Countries.
  5. Martínez-González, M. A., Gea, A., & Ruiz-Canela, M. (2019). The Mediterranean diet and cardiovascular health. Circulation Research, 124(5), 779–798. https://doi.org/10.1161/circresaha.118.313348
  6. Dayi, T., & Ozgoren, M. (2022). Effects of the Mediterranean diet on the components of metabolic syndrome. Journal of Preventive Medicine and Hygiene, 63(2 Suppl 3), E56–E64. https://doi.org/10.15167/2421-4248/jpmh2022.63.2S3.2747
  7. Mentella, M. C., Scaldaferri, F., Ricci, C., Gasbarrini, A., & Miggiano, G. a. D. (2019). Cancer and Mediterranean diet: A review. Nutrients, 11(9), 2059. https://doi.org/10.3390/nu11092059
  8. Tosti, V., Bertozzi, B., & Fontana, L. (2017). Health benefits of the Mediterranean diet: Metabolic and molecular mechanisms. The Journals of Gerontology Series A, 73(3), 318–326. https://doi.org/10.1093/gerona/glx227
  9. Akbar, A., & Shreenath, A. P. (2023, May 1). High fiber diet. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK559033/
  10.  Xiong, R., Zhou, D., Wu, S., Huang, S., Saimaiti, A., Yang, Z., Shang, A., Zhao, C., Gan, R., & Li, H. (2022). Health benefits and side effects of short-chain fatty acids. Foods, 11(18), 2863. https://doi.org/10.3390/foods11182863
  11. Dai, J., Jones, D. P., Goldberg, J., Ziegler, T. R., Bostick, R. M., Wilson, P. W., Manatunga, A. K., Shallenberger, L., Jones, L., & Vaccarino, V. (2008). Association between adherence to the Mediterranean diet and oxidative stress. The American Journal of Clinical Nutrition, 88(5), 1364–1370. https://doi.org/10.3945/ajcn.2008.26528
  12. Aravind, S. M., Wichienchot, S., Tsao, R., Ramakrishnan, S., & Chakkaravarthi, S. (2021). Role of dietary polyphenols on gut microbiota, their metabolites and health benefits. Food Research International, 142, 110189. https://doi.org/10.1016/j.foodres.2021.110189
  13. Muro, P., Zhang, L., Li, S., Zhao, Z., Jin, T., Mao, F., & Mao, Z. (2024). The emerging role of oxidative stress in inflammatory bowel disease. Frontiers in Endocrinology, 15. https://doi.org/10.3389/fendo.2024.1390351
  14. Davani-Davari, D., Negahdaripour, M., Karimzadeh, I., Seifan, M., Mohkam, M., Masoumi, S., Berenjian, A., & Ghasemi, Y. (2019). Prebiotics: Definition, types, sources, mechanisms, and clinical applications. Foods, 8(3), 92. https://doi.org/10.3390/foods8030092
  15. O’Malley, K., Willits-Smith, A., & Rose, D. (2023). Popular diets as selected by adults in the United States show wide variation in carbon footprints and diet quality. American Journal of Clinical Nutrition, 117(4), 701–708. https://doi.org/10.1016/j.ajcnut.2023.01.009
  16. Wicaksono, W. A., Cernava, T., Wassermann, B., Abdelfattah, A., Soto-Giron, M. J., Toledo, G. V., Virtanen, S. M., Knip, M., Hyöty, H., & Berg, G. (2023). The edible plant microbiome: Evidence for the occurrence of fruit and vegetable bacteria in the human gut. Gut Microbes, 15(2). https://doi.org/10.1080/19490976.2023.2258565
  17. Burt, K. (2021). The whiteness of the Mediterranean diet: A historical, sociopolitical, and dietary analysis using Critical Race Theory. Journal of Critical Dietetics, 5(2), 41–52. https://doi.org/10.32920/cd.v5i2.1329