Dr. Ramon Estruch: “The Mediterranean diet is good for everyone: 95% of the population can benefit from it”

First of all: what is the Mediterranean diet?

It is the diet typical of the Mediterranean countries, especially those in Southern Europe, but not so much those in North Africa.  Its fame dates back to the 1960s when a study was carried out comparing the incidence of heart disease and cardiovascular mortality in seven different countries.  It was found that the incidence was much lower in Mediterranean countries—especially Italy and Greece—and even in comparison with other richer countries such as the United States or Finland.  And when the cause of these differences was investigated, it was concluded that it was lifestyle and, more specifically, eating habits. Then, Dr. Ancel Keys, a professor of nutrition from Minnesota, published a book on the Mediterranean diet, which became very popular and all the studies on this subject began.

Why is it so beneficial?

A large number of studies have been carried out comparing it with other dietary patterns, and it has been seen that it really has a clear effect in reducing various illnesses. The most common and frequently studied illness is cardiovascular disease, where it has been clearly shown that it is the optimal pattern for both prevention and treatment. However, it is also beneficial for diabetes, neurodegenerative diseases such as cognitive impairment and Alzheimer’s disease, as well as for the prevention of some types of cancer. Between 70% and 80% of diseases are linked to lifestyle and dietary habits in one way or another.  This is why diet is so important in the prevention of almost all noncommunicable chronic diseases.

What types of cancer can be prevented with the Mediterranean diet?

But the benefits do not depend exclusively on diet - it is a lifestyle.

Diet is the aspect that has been studied the most because, from a technical point of view, it is easier, but it is thought that it is the whole package that makes the subject interesting: it includes physical activity and, as we have a better climate, people can go out for walks more and do sport.  Psychosocial aspects such as sociability, sharing meals and going out for snacks are also very important… We believe that all this has great added value.

You lead the research group on "Cardiovascular risk, nutrition and ageing".

The history of the group is that in the years 2002-2003 the Ministry of Health was awarded grants to set up thematic networks, large grants to be able to carry out extensive research and thus compete with other European and North American countries in terms of research. At that time, we were joined by people who were carrying out research on olive oil, people who were carrying out research on nuts, such as Dr. Ros, or my group who were studying the effects of moderate wine consumption as protection against cardiovascular disease. We thought that all this was encompassed by the Mediterranean diet and we presented a very ambitious project: PREDIMED. They gave us the funding—not as much as we wanted—but that is how we were able to start the study.

And what conclusions have you reached?

Later, as many as 12 groups from research centres all over Spain joined the study, and in total we included 7,447 people at high vascular risk in the PREDIMED trial.  One third followed a Mediterranean diet supplemented by extra virgin olive oil, another third followed a Mediterranean diet supplemented by nuts, and the rest constituted the control group, who followed a diet low in all types of fat.  We monitored them for five years on average, and saw that those who followed the Mediterranean diet, both the olive oil and the nuts groups, had a 30% lower incidence of heart attacks, strokes and cardiovascular death than the control group. We published this study in the New England Journal of Medicine in 2010, and it had a huge impact, which exceeded all expectations.  As a result, the majority of both American and European clinical guidelines on cardiovascular disease and stroke have indicated that the Mediterranean diet is one of the healthiest in the world. Therefore, we have achieved worldwide recognition for the Mediterranean diet.

But surely there is room for improvement. How?

There is always room for improvement: when we started PREDIMED, people mainly used to eat regular olive oil, and now we know that extra virgin olive oil is far better. It is also clear that we need to eat more fish than we do at present, especially oily fish.  And more legumes, which are an important element in the Mediterranean diet, and people don’t eat enough of them. Experts recommend three or four servings of legumes a week, but for whatever reason—because they are hard to cook, etc.— not enough legumes are consumed.

Recently, there has been a lot of talk about meat consumption. It is excessive in the Mediterranean diet?

In the original Mediterranean diet, that of Southern Europe in the 1960s, people ate meat once or twice a month.  That is too little, but today people eat too much meat. What we recommend is to eat more white meat than red meat, but not to stop eating red meat because it contains proteins, and also vitamin B12 and iron as well as other nutrients.  It is a good idea to recommend a diet rich in vegetables. However, if you then become deficient in vitamins and need to supplement your diet with pills, it does not seem very healthy from a medical point of view.

It is also said that the Mediterranean diet is more sustainable. Why?

The Mediterranean diet is one of the most sustainable diets there is: a European study corroborates this. That it is because it is based above all on the consumption of vegetables rather than meat, which has a higher carbon footprint, a greater impact on the greenhouse effect, and involves higher water consumption, etc. The key to the planetary diet, to making our food more sustainable, would be to reduce meat consumption and also the consumption of starchy foods such as potatoes.  And this would allow us to eat a little more fish, a little more fruit, vegetables and legumes.

In a globalized and fast-paced world, what can be done to avoid moving away from this food pattern?

The Mediterranean diet involves cooking a little.  It’s what I was saying earlier about legumes, that people don’t eat them very much because they are more time-consuming to cook.  What we recommend is to plan and buy what you will eat throughout the entire week.  This way you buy what you need and end up saving money, because you choose more seasonal products that are usually cheaper and tastier.  Likewise, cooking does not take long if you plan well. We calculated that in 10 or 15 minutes you can make a well-balanced lunch or dinner.

Another of your areas of study is how each person’s genetic characteristics influence their diet.  What conclusions have you reached?

What we have seen in PREDIMED is that the Mediterranean diet is good for everyone inasmuch as 95% of the population can benefit from it. There is always someone who does not because they have a nut allergy, for example... but only a few people.  We even saw that there is a genetic polymorphism that predisposes some people to strokes and we detected in the control groups that there was a much higher incidence of stroke in the people who did not follow the Mediterranean diet and had this polymorphism. However, in the Mediterranean diet group, the differences were evened out.  I was greatly surprised by this at first, but not it's clear: epigenetics play a very important role and means that if you follow a good diet the harmful genes you inherit do not express themselves. This shows us that the Mediterranean diet works, that it is not something new like the vegetarian diet, but it has existed for many centuries.  And thanks to this, it has gradually been improved and the final result is what we have today.