The Mediterranean Diet (MedDiet): There’s more to it than olives and grape leaves

Centered around the consumption of whole and unprocessed foods, we hear how following a Mediterranean diet can bring long-term health benefits, including mitigating the risk of common diseases

The popular press seems to publish articles daily about the Mediterranean diet. This eating pattern has been shown to reduce the risk of many of our most formidable health problems, including diabetes, hypertension, cancer, heart disease, and even depression. ⁽¹⁾ In January 2023, the New York Times published an article: The Mediterranean Diet Really Is that Good for you. Here’s Why, ⁽²⁾ describing the many benefits of this “bedrock of virtuous eating.”

Many nutrition professionals prefer to call the MedDiet an eating pattern rather than a “diet”, which implies a restrictive and onerous weight loss diet. If you are “on a diet,” there will likely be a time, or many times, when you are “off” the diet, while an eating pattern reflects long-term habits.

After years of mistaken recommendations to restrict dietary fat, due in part to limited research or misinterpretation of available data, the current and ever-growing body of evidence suggests that a diet higher in good quality fat is most health promoting. ^{(1), (3)} While once recommending no more than 30% of calories from fat, we now consider 35- 45% to be a healthful fat intake.

Good quality fat means primarily plant-based oils, with extra virgin olive oil seeming to rise to the top, though the benefits of corn, safflower, soybean, canola, and other non-tropical oils have not been entirely proven. Because fats and oils tend to carry and enhance the flavor of food, ⁽⁴⁾ MedDiet meals are much more palatable, and condiments often thought to be taboo, such as mayonnaise and full fat salad dressing, are actually healthful alternatives to “no-fat” or “low-fat” options which may have high fructose corn syrup as one of the first ingredients.

Cultural relevance

Some have expressed concern that the MedDiet is a “white diet” and reflects “systemic racism” ⁽⁵⁾ by ignoring the health benefits of other cultural eating patterns. This is a misinterpretation of the MedDiet, assuming it comprises particular foods rather than informed by the combination of macro and micronutrients shown to have health-promoting effects. For example, while olives and grape leaves might convey the healthy oils and vegetable benefits in Mediterranean meals, avocado oil, macadamia oil, and moringa leaves provide similar nutrient composition but are culturally rooted in African meal patterns.

The MedDiet principles of healthy oils, whole grains, nuts/seeds, and fruits and vegetables can be applied to any cultural eating pattern. Our research team has been developing and testing the “Med-South” diet ⁽⁶⁾ , which adapts the MedDiet to southeastern food availability and taste preferences. ⁽⁷⁾ We have found positive impacts on dietary intake, blood pressure, and weight. ⁽⁶⁾

Unfortunately, the “westernization” of many traditional diets includes significant consumption of ultra-processed foods, typically high in refined carbohydrates, sugar, and sodium. Perhaps this should be referred to as the “white diet.”

MedDiet throughout the lifecycle

Too little attention has been paid to introducing the MedDiet early in the life cycle to break the generational cycle of chronic disease where the unhealthy diet of one generation passes on adverse epigenetic impacts to future generations. ⁽⁸⁾

A recent study published in JAMA Network Open ⁽⁹⁾ showed that a MedDiet intervention during pregnancy significantly improved the child’s neurodevelopment at two years. While more research is needed, there is some promising research that transitioning young infants from breastmilk to a MedDiet is also beneficial. (10) Approximately 40-50% of the energy in breast milk comes from fat. Still, babies are often transitioned to rice cereal and strained fruit/vegetables that are very high in carbohydrates and low in fat.

Recent research has reversed our prior thinking that infants should avoid all potential food allergens. Early introduction of these foods, such as peanuts, can prevent allergies and contribute to a Med-style diet. ⁽¹¹⁾ Infants can be given texture appropriate (salt and sugar limited) versions of table foods, allowing them to begin a Med-style diet when starting complementary foods (assuming parents are eating the MedDiet). At the opposite end of the life cycle, in addition to chronic disease risk reduction, there is mounting evidence that greater adherence to the MedDiet is associated with slower cognitive decline and a lower risk of developing Alzheimer’s disease. ⁽¹²⁾

The MedDiet and the microbiome

Perhaps second only to the MedDiet in terms of prominence in nutrition- related news stories is the gut microbiome ^(13,14) made up of the microorganisms, including bacteria, that live in the digestive tracts of animals. A dysfunctional microbiome can negatively impact many common chronic conditions, including obesity, type 2 diabetes, fatty liver disease, and dementia. ⁽¹⁵⁾ Not surprisingly, the MedDiet has been linked to a happier and healthier gut microbiome, which can, in turn, benefit the human “host.” ⁽¹⁶⁾

Food is medicine and nutrition security

To encourage more physicians to counsel patients about the MedDiet eating pattern, our research team has been developing and testing tools to facilitate brief counseling sessions and referral to dietitians, health educators, and community health workers. ^(17,18) There is growing interest in “Food is Medicine” and Medically Tailored Meals, which can be personalized to both health conditions and cultural preferences. ⁽¹⁹⁾

The focus is shifting from “food insecurity” to “nutrition security” to address nutritional quality as well as access. ⁽²⁰⁾ Recognizing the potential cost savings of prevention, health insurance companies and state governments, through Medicaid waivers, are including fresh produce boxes and healthy prepared meals as benefits in health plans. This is an opportunity for longer term and more equitable support for individuals wanting to adopt the MedDiet eating pattern.

Early benefits and sticking to it

Studies indicate that changing to a healthful MedDiet favorably impacts health parameters such as blood pressure, blood lipids, blood glucose, and the microbiome in days to weeks ⁽²¹⁾ and favorably impacts health outcomes over the long run. ⁽²²⁾

On the flip side, following a “crash diet” can improve short term outcomes such as weight, but is likely more restrictive and less palatable than the MedDiet, often resulting in “backsliding” and quick loss of the initial benefits. Learning to enjoy the dietary pleasures of roasted vegetables, nuts, fresh berries, full fat dressings and spreads, and whole grain breads rather than ultra-processed foods that are so readily available can set one up for a lifetime of enjoyable eating and good health.

References

1. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts | NEJM https://www.nejm.org/doi/full/10.1056/NEJMoa1800389
2. https://www.nytimes.com/2023/01/06/well/eat/mediterranean-diet-health.html
3. Evaluation of the Quality of Evidence of the Association of Foods and Nutrients With Cardiovascular Disease and Diabetes: A Systematic Review – PubMed (nih.gov) https://pubmed.ncbi.nlm.nih.gov/35113165/
4. Functions of Fat in Food (thespruceeats.com)
5. The whiteness of the Mediterranean Diet: A historical, sociopolitical, and dietary analysis using Critical Race Theory | Journal of Critical Dietetics (torontomu.ca) 
6. https://pubmed.ncbi.nlm.nih.gov/27495295/
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8. https://pubmed.ncbi.nlm.nih.gov/33806342/
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10. Mediterranean Diet-Based Interventions to Improve Anthropometric and Obesity Indicators in Children and Adolescents: A Systematic Review with Meta-Analysis of Randomized Controlled Trials – PubMed (nih.gov) https://pubmed.ncbi.nlm.nih.gov/37127186/
11. Early introduction of peanut reduces peanut allergy across risk groups in pooled and causal inference analyses – Logan – 2023 – Allergy – Wiley Online Library https://onlinelibrary.wiley.com/doi/full/10.1111/all.15597
12. Mediterranean Diet, Cognitive Function, and Dementia: A Systematic Review on JSTOR https://www.jstor.org/stable/23486687
13. Mediterranean diet linked to gut microbiome improvements (medicalnewstoday.com) https://www.medicalnewstoday.com/articles/mediterranean-diet-linked-to-gut-microbiome-improvements
14. Age-dependent changes in GI physiology and microbiota: time to reconsider? | Gut (bmj.com) https://gut.bmj.com/content/67/12/2213
15. https://www.sciencedirect.com/science/article/abs/pii/B9780081022689000100
16. https://pubmed.ncbi.nlm.nih.gov/34020445/
17. Med-South Lifestyle Program – Center for Health Promotion and Disease Prevention (unc.edu) https://hpdp.unc.edu/med-south-lifestyle-program/
18. https://pubmed.ncbi.nlm.nih.gov/36154700/
19. A Food is Medicine approach to achieve nutrition security and improve health – PubMed (nih.gov) https://pubmed.ncbi.nlm.nih.gov/36202998/
20. Prioritizing Nutrition Security in the US – PubMed (nih.gov) https://pubmed.ncbi.nlm.nih.gov/33792612/
21. https://pubmed.ncbi.nlm.nih.gov/9099655/
22. https://pubmed.ncbi.nlm.nih.gov/33067162/

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