The Mediterranean Way of Life, Part 1: Why People Around the Mediterranean Live Longer

Since the 1950s, nutrition researchers have asked why people living around the Mediterranean tend to live longer and suffer fewer cardiovascular diseases – and the answer doesn't lie in a single ingredient, but in the interplay of an entire dietary pattern that is now one of the most extensively studied diets in existence.

This article is the first part of a four-part series on the Mediterranean way of life. After diet as the foundation, Part 2 looks at stress and relaxation, Part 3 at social connection and community as a health factor, and Part 4 at sunlight and vitamin D. We're starting with the area that's been researched the most: food itself.

What exactly defines the Mediterranean diet?

The term "Mediterranean diet" doesn't describe a single recipe, but a pattern based on the traditional eating habits found in countries such as Greece, southern Italy and Spain, first systematically described by American physiologist Ancel Keys from the 1950s onward. It's characterised by a high proportion of vegetables, fruit, whole grains, legumes and nuts, olive oil as the main fat source, regular fish consumption, moderate amounts of dairy and poultry, and a markedly reduced share of red meat and heavily processed foods.

What the research shows about cardiovascular health

The most robust data come from large randomised controlled trials (RCTs). In the Spanish PREDIMED study, one of the most influential nutrition trials ever conducted, the group following a Mediterranean diet (supplemented with olive oil or nuts) showed roughly a 30 percent risk reduction for the composite endpoint of heart attack, stroke and cardiovascular death compared with a low-fat control diet; stroke risk alone was significantly reduced. The more recent CORDIOPREV trial, conducted in people with existing cardiovascular disease, found around a 27 percent reduction in major cardiovascular events compared with a low-fat diet. Already in the 1990s, the Lyon Diet Heart Study observed an even more pronounced risk reduction for recurrent events in heart attack survivors. A recent systematic review summarising 24 studies concludes that greater adherence to the Mediterranean diet is associated with lower overall mortality and lower cardiovascular risk, both in the general population and in people with pre-existing disease.

An important caveat: authors of several reviews point out that the benefit likely cannot be attributed to a single component, but rather to the interaction of unsaturated fats, fibre, micronutrients and polyphenols across the whole dietary pattern.

What role olive oil and polyphenols play in the studies

Olive oil, particularly extra virgin olive oil, contains polyphenols such as hydroxytyrosol and oleuropein alongside unsaturated fats. For olive oil with a defined minimum polyphenol content, EU regulation authorises a specific, content-linked statement regarding the protection of blood lipids from oxidative stress. A meta-analysis of ten randomised controlled trials also found dose-dependent effects of polyphenol-rich olive oil on oxidised LDL cholesterol, while the effect on standard cholesterol levels overall remained inconsistent. A smaller placebo-controlled human study on isolated hydroxytyrosol observed improvements across several oxidation and inflammation markers; this is a single study with a limited number of participants, and its findings would need confirmation through further research.

How the Mediterranean diet affects gut flora and inflammation markers

A growing area of research examines how the Mediterranean diet works via the gut microbiome. A population-based observational study from northern Germany, involving over 600 participants, found that people with higher adherence to the Mediterranean pattern had lower visceral fat tissue and lower CRP levels (an inflammation marker) – part of this association could be statistically attributed to specific gut bacteria. A systematic review of controlled trials describes that, compared with other dietary patterns, the Mediterranean diet is more often associated with an increase in short-chain fatty acid-producing bacteria and a decrease in several inflammation markers (including CRP and IL-6). These associations are largely observational or short-term interventional; they point to plausible mechanisms but do not yet establish long-term causality for any individual.

Why fish and marine omega-3 fatty acids are a central building block

Regular consumption of fish and seafood is considered one of the defining building blocks of the Mediterranean diet. Fish itself doesn't produce the long-chain omega-3 fatty acids EPA and DHA; it absorbs them through the food chain – the original producers are marine microalgae. Anyone who eats little or no fish for ethical, taste or sustainability reasons can obtain these fatty acids directly from algae oil instead. This doesn't change the fundamental importance of EPA and DHA within the Mediterranean dietary pattern – only the source.

Safety, limitations and who should take particular care

The Mediterranean diet is consistently regarded as safe in the research literature and is also recommended during pregnancy and breastfeeding – with the exception that alcohol (in the form of moderate red wine consumption, as featured in some Mediterranean study protocols) should be avoided entirely during pregnancy and breastfeeding. For people on blood-thinning medication (vitamin K antagonists), a sudden, sharp increase in leafy green vegetable intake can affect vitamin K levels and therefore medication effect; a gradual rather than abrupt dietary change, together with consultation with the treating physician, is advisable here. In case of fish allergy, the fish component should be replaced accordingly, for example with plant-based omega-3 sources. Anyone with existing cardiovascular disease or taking medication should discuss larger dietary changes with a healthcare professional.

Conclusion: what's well established – and what remains open

For the cardiovascular effects of the Mediterranean diet, PREDIMED, CORDIOPREV and the Lyon Diet Heart Study together provide a rare density of large randomised controlled trials – unusually solid for a field of nutrition research where RCTs are practically difficult to run. The evidence base is less clear-cut for gut flora and inflammation markers: here, the evidence comes mostly from observational studies and smaller intervention trials, which point to plausible mechanisms but don't yet establish conclusive causality for individual biomarkers. What is not in dispute is that this is a dietary pattern as a whole – no single "miracle ingredient" can be isolated from the research.

This article is for general informational purposes only and does not replace individual medical or nutritional advice. Dietary supplements are not a substitute for a balanced and varied diet and a healthy lifestyle.