Why is the Mediterranean diet good for your health?
Last time, I shared the ‘science of lipids,’ explaining how olive oil (oleocanthal) and oily fish (omega-3s and resolvins), which are the cornerstones of the Mediterranean diet, suppress chronic inflammation in the body [1].
You might have thought, ‘If I change my oil and eat fish at least twice a week, isn’t that enough to improve my diet?’
However, the true reason the Mediterranean diet continues to receive overwhelming acclaim in the world’s top medical journals (such as the NEJM and Lancet) lies not in lipids alone, but in the comprehensive synergistic effects of the ‘hidden stars’ that grace the dining table [2].
These include ‘unrefined grains,’ ‘vegetables,’ ‘nuts,’ and ‘traditional fermented foods’ that people in the Mediterranean region consume daily.
How do these act within the body to protect our cells and blood vessels?
This time, I will delve into the answers to ‘three questions’ that longevity medicine has elucidated, along with the latest evidence.
Question 1: Why do ‘unrefined grains’ and ‘legumes’ stop inflammation in the gut?
Refined carbohydrates like white rice and white bread have most of their dietary fiber and micronutrients removed during the manufacturing process.
Consuming these causes blood sugar levels to spike, leading to the production of aging substances called AGEs (Advanced Glycation End-products) in the body, which are a cause of chronic inflammation [3].
On the other hand, ‘unrefined grains’ like barley and oatmeal, which are staples of the Mediterranean diet, as well as legumes like ‘lentils and chickpeas,’ contain abundant ‘soluble and insoluble dietary fiber.’
This dietary fiber is not broken down by human digestive enzymes; it reaches the large intestine and serves as food for gut bacteria (beneficial bacteria).
The substances produced during the process of gut bacteria fermenting and breaking down dietary fiber are called ‘Short-Chain Fatty Acids (SCFA)’ [4].
Representative short-chain fatty acids like ‘butyrate’ and ‘propionate’ possess surprising anti-inflammatory mechanisms [4].
● They strengthen the junctions between intestinal mucosal cells, preventing ‘leaky gut syndrome,’ where undigested food and toxins leak into the bloodstream [4].
● They activate immune cells called regulatory T cells (Treg), directly blocking the runaway immune system and systemic inflammatory responses at the molecular level [4, 5].
In other words, eating unrefined grains and legumes is not just about filling your stomach; it is about ‘delivering the raw materials for gut bacteria to produce anti-inflammatory substances.’
Question 2: Why is it better to ‘eat vegetables and nuts in combination’?
You should be cautious about the idea that ‘since I take vitamin C and vitamin E supplements, I don’t need many vegetables.’
Numerous large-scale meta-analyses have revealed that taking single vitamin supplements does not reduce the risk of death from cardiovascular disease or cancer [6].
The Mediterranean diet is overwhelmingly effective because it involves the simultaneous intake of thousands of types of ‘polyphenols’ and ‘phytochemicals’ found in a variety of vegetables, fruits, and nuts.
Lycopene in tomatoes, quercetin in Mediterranean vegetables, and phenolic acids in nuts form an ‘antioxidant network’ where they prevent each other’s oxidation and enhance their effects within the body [2, 7].
Furthermore, nuts like ‘walnuts’ and ‘almonds,’ which are essential to the Mediterranean diet, contain not only unsaturated fatty acids but also abundant magnesium and L-arginine.
In a sub-analysis of the global clinical trial ‘PREDIMED study,’ it was demonstrated that in the group that added nuts (about 30g per day) to their daily diet, endothelial function improved significantly, and the risk of stroke onset decreased by approximately 39% [8].
The reason the Mediterranean diet is considered healthy is precisely because of the powerful synergistic effects that can only be obtained by combining various colored ingredients, rather than relying on a single component.
Question 3: Does the Mediterranean diet include ‘fermented foods’?
You might have a strong image of ‘fermented foods’ as Japanese miso or natto, but the Mediterranean diet tradition also has its own unique fermentation culture.
These are ‘Greek yogurt,’ ‘natural cheeses (feta and pecorino),’ and ‘brined olives.’
It has been pointed out that ultra-processed foods (UPF) mass-produced in factories and dairy products containing artificial additives carry the risk of damaging the gut environment [9].
However, traditional fermented foods that have long been enjoyed in the Mediterranean region are rich in live probiotics (lactic acid bacteria and bifidobacteria).
The ‘peptides’ and ‘lactic acid’ produced through traditional lactic acid fermentation work to suppress the growth of bad bacteria in the gut and maintain the diversity of the gut flora [10].
People in the Mediterranean region do not consume these fermented dairy products in large quantities as a main dish, but rather incorporate them ‘in small, appropriate amounts every day’ as salad toppings or side dishes.
This exquisite balance is the secret to maintaining gut barrier function while preventing the excessive intake of saturated fatty acids.
Summary & Habits for Tomorrow
● Unrefined grains and legumes cause gut bacteria to produce ‘short-chain fatty acids,’ suppressing systemic immune runaway
● Vegetables and nuts create an antioxidant barrier through the ‘synergistic effect’ of a wide variety of polyphenols, rather than single components
● Traditional fermented foods like Greek yogurt and natural cheese support the diversity of the gut flora
The Mediterranean diet is by no means a special diet that requires expensive ingredients. It is a ‘system of combining ingredients that delights your body’s cells and gut bacteria.’
Please try the following three small changes in your shopping starting tomorrow.
● Be conscious of ‘browning’ your staple foods
Just by mixing pearl barley or barley into white rice, or choosing ‘100% whole wheat’ when selecting bread, the production of short-chain fatty acids in the gut will increase dramatically.
● Change your snack-time junk food to ‘a handful of plain, unsalted nuts’
Walnuts, in particular, are rich in plant-based omega-3s (alpha-linolenic acid) and help support the rejuvenation of blood vessels.
● Add ‘boiled beans (chickpeas or soybeans)’ to salads and soups
By keeping canned or packaged boiled beans on hand and adding a pinch to your daily cooking, you can easily boost your dietary fiber and plant-based protein intake.
When ‘oils and fish’ are combined with ‘unrefined grains, diverse vegetables, and fermented foods,’ the strongest fire-extinguishing system to calm chronic inflammation is completed within your body.
To deliver the gift of optimal health to your future self 10 years from now, why not take a step you can start today?
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References
1. Calder, P. C. (2015). Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance. Biochimica et Biophysica Acta (BBA) – Molecular and Cell Biology of Lipids, 1851(4), 469-484.
2. Estruch, R., et al. (2013). Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. New England Journal of Medicine, 368(14), 1279-1290.
3. Cordain, L., et al. (2005). Origins and evolution of the Western diet: health implications for the 21st century. American Journal of Clinical Nutrition, 81(2), 341-354.
4. Koh, A., et al. (2016). From Dietary Fiber to Host Physiology: Short-Chain Fatty Acids as Key Bacterial Metabolites. Cell, 165(6), 1332-1345.
5. Furusawa, Y., et al. (2013). Commensal microbe-derived butyrate induces the differentiation of colonic regulatory T cells. Nature, 504(7480), 446-450.
6. Bjelakovic, G., et al. (2012). Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database of Systematic Reviews, (3), CD007176.
7. Jacobs, D. R., & Tapsell, L. C. (2007). Food synergy: an operational concept for understanding nutrition. Public Health Nutrition, 10(10A), 1197-1206.
8. Ros, E., et al. (2014). Nutrition and Cardiovascular Health: The PREDIMED Study. Advances in Nutrition, 5(3), 330S-336S.
9. Srour, B., et al. (2019). Ultra-processed food intake and risk of cardiovascular disease: prospective cohort study (NutriNet-Santé). BMJ, 365, l1451.
10. Marco, M. L., et al. (2017). Health benefits of fermented foods: microbiota and beyond. Current Opinion in Biotechnology, 44, 94-102.