D ecades of research suggest that a Mediterranean way of eating can be really good for your health. People have been told for years that enjoying the delicious fresh foods of the Mediterranean, like tomatoes, focaccia, and olive oil, can reduce the risk of heart attacks and type 2 diabetes. Surprisingly, this is not just a hype. Evidence has been building for over 50 years that the Mediterranean diet can genuinely improve health in many ways.
“We have long-term, large clinical trials with hard clinical events as the outcomes,” says Miguel Martinez-Gonzalez at the University of Navarra in Pamplona, Spain. Even UNESCO recognized the value of the Mediterranean diet by adding it to its Representative List of the Intangible Cultural Heritage of Humanity a decade ago.
Despite all the praise, understanding what exactly in the diet leads to such benefits has been challenging. Nutritionists can’t agree on the exact form the diet should take, and non-dietary factors like eating as a family and cooking at home also play a role. However, over the past decade, researchers have started to identify which components of the diet offer the most significant health benefits.
The fame of the Mediterranean diet goes back to US physiologist Ancel Keys and his wife, Margaret. In the 1940s, Ancel argued that saturated fats, mostly found in animal products, are a major cause of heart disease. He believed that unsaturated fats, more common in plant products and fish, are a healthier alternative. The Seven Countries Study, which started in 1956, compared diet and health in various regions, confirming the link between eating unsaturated fat and a reduced risk of heart disease.
During their work, Ancel and Margaret observed a large number of centenarians in southern Italy, where the diet was high in unsaturated fat. This discovery led them to believe that the local diet was the key to longevity. They even relocated to southern Italy and lived long lives themselves, which added further credibility to their message. As a result, the Mediterranean diet became increasingly popular.
In addition, the Mediterranean diet’s health benefits have been supported by decades of research. Despite some uncertainties about its exact form, we now have a better understanding of which components contribute to its positive effects on health.
Over time, confusion has emerged about what exactly constitutes the Mediterranean diet. One thing is clear: it doesn’t include large quantities of indulgent foods like lasagne, moussaka, pizza, and kofta kebabs commonly associated with Italy, Greece, and Turkey. Interestingly, many locals don’t even follow the version of the diet linked to health benefits.
Defining the diet has been a challenge, but one widely used measure is the Mediterranean Diet Score (MDS), developed in the 1990s by Antonia Trichopoulou. According to MDS, a true Mediterranean diet includes plenty of vegetables, legumes, fruits, nuts, cereals, and a moderate amount of fish. It limits meat, poultry, and dairy while surprisingly allowing a moderate amount of alcohol, typically red wine.
Another definition, the Mediterranean Diet Adherence Screener, introduced in 2011, considers the use of olive oil in cooking (favourable) and the consumption of sugary drinks (undesirable). Over the years, researchers have made adjustments to the standard definition, considering dairy as neutral and reducing the recommended alcohol intake. However, there’s no formal consensus on the exact profile of the diet due to constant tweaking and redefining.
Despite debates over specific food items, large-scale studies confirm the health benefits of a generalized Mediterranean diet. It is widely recognized as a top dietary intervention to prevent heart attacks and strokes. For example, the CORDIOPREV study in 2022 indicated that following the Mediterranean diet significantly reduces the chances of a second cardiovascular event in those who have already had one.
There is also evidence that the diet lowers the risk of developing cardiovascular disease in the first place. A 2020 Cochrane review of 22 trials found “moderate quality evidence” supporting this, and a Harvard University overview the following year revealed “strong evidence” that the diet protects cardiovascular health.
These protective properties may explain why Italy has a lower mortality rate from cardiovascular disease compared to the global average, as researchers believe that a significant portion of the population follows the Mediterranean diet, influencing the statistics.
The Mediterranean diet offers more than just heart health benefits. According to a 2020 review, those who follow this diet are 20 per cent less likely to develop type 2 diabetes. There’s also a suggestion that it might reduce the risk of certain cancers, such as breast and bladder cancer, although more evidence is needed for confirmation.
Miguel Martinez-Gonzalez, a researcher, is confident in the diet’s positive impact, stating that no study has shown harm. However, the Mediterranean diet may not work the same for everyone. The Moli-sani study, a large investigation in southern Italy, revealed in a 2018 update that the diet’s cardiovascular benefits were only observed in highly educated and higher-income individuals, leaving others without the same protection.
Marialaura Bonaccio, leading the study, suggests that the quality of the food people eat matters. While studies ask about the quantity of fruits consumed, they often overlook details like the type, how it was grown, or its form. This oversight may affect the benefits observed. Individuals with lower incomes may be limited to cheaper, less nutritious frozen or processed foods, impacting the effectiveness of their diet.
Researchers are now examining specific components of the Mediterranean diet to understand its health benefits better. Extra-virgin olive oil is emerging as a key ingredient. It is unique, being derived from pressed and ground fresh olives, unlike other oils produced with chemicals and high temperatures. Extra-virgin olive oil, rich in unsaturated fats, shows greater health benefits compared to refined olive oil.
Studies have found that extra-virgin olive oil consumption is linked to lower blood pressure, higher levels of “good” cholesterol, and lower levels of “bad” cholesterol. The health benefits are attributed not only to unsaturated fats but also to additional components like polyphenols. Polyphenols, found in extra-virgin olive oil, are believed to contribute significantly to its positive effects, influencing factors such as gut microbiome and blood pressure.
The health benefits of extra-virgin olive oil might not solely rely on the microbiome; personal genetics could also play a role. Evidence suggests that specific nutrients in olive oil and other Mediterranean diet components may influence genes related to inflammation. Some even propose tailoring diet recommendations based on individual genetics for better health outcomes.
For those eager to adopt the Mediterranean diet, there’s a growing divide among researchers. Some doubt its universal effectiveness beyond the Mediterranean region, emphasizing the need for each country to discover its own traditional diet suited to local characteristics. However, others are optimistic, suggesting that replicating the diet’s general features is more crucial than adhering to specific foods.
While certain components like extra-virgin olive oil are considered vital, there’s flexibility in vegetable choices. Northern European vegetables like cabbages and carrots can be suitable alternatives. Despite its importance, the rising cost of extra-virgin olive oil poses a challenge.
Martinez-Gonzalez advocates for introducing taxes on ultra-processed foods and using the revenue to subsidize healthier options. He believes this would lead to improved public health and reduced medical care costs for governments. However, even with access to high-quality foods, the Mediterranean diet’s lifestyle component may be crucial. Ancel and Margaret Keys’ studies suggest that factors like residing in the countryside, engaging in physical work, and preparing meals leisurely in social groups contribute to overall well-being.
Notably, the Mediterranean villagers’ way of living in the 20th century included preparing their own food and enjoying meals together, which linked to increased happiness and life satisfaction. However, implementing the diet may require dedicating time to cooking and socializing. Combining these lifestyle factors with an active routine could allow everyone to experience the health benefits associated with the Mediterranean diet, echoing the experiences of Ancel and Margaret Keys during their visits to southern Italy in the 1950s.
In sum, the Mediterranean diet has gained widespread recognition for its positive impact on health, particularly in reducing the risk of heart attacks and type 2 diabetes. Despite ongoing debates about its exact definition, the emphasis on fresh vegetables, fruits, nuts, cereals, and moderate fish intake remains consistent. The Mediterranean Diet Score guides individuals toward healthier choices, with extra-virgin olive oil emerging as a key component for its rich unsaturated fats and polyphenols. While some researchers question its universal effectiveness, others advocate for replicating its general features rather than adhering strictly to specific foods. Beyond physical health, the diet’s lifestyle component, including cooking at home and socializing during meals, is considered crucial for overall well-being. Despite challenges like the rising cost of olive oil, the potential rewards in terms of health and happiness make adopting the Mediterranean diet a worthwhile consideration for those seeking a balanced and fulfilling lifestyle.
Reference: New Scientists,
13 January 2024
