TALKING POINTS

The History of the Mediterranean Diet

This reference helps you talk about what you have learned with others. Talking Points also serve as a reminder for when, in the future, you want a refresher on the main highlights of this course. Schedule tea with a friend and have a conversation about this subject!

Note: Medi diet = Mediterranean diet

So, what exactly do we mean by the "Medi diet?" Could it be any food or dietary pattern from that part of the world?

When scientists and dietitians refer to the "Medi diet," they are talking about a pattern of eating inspired by the traditional diet of people living in olive-producing countries like Spain, Greece, and southern Italy, generally around the 1950s.

This is a diet high in plants, seafood, nuts and seeds, legumes, and olive oil. The diet is relatively low in saturated fat because much of the fat in the diet comes from olive oil and fish (rich in monounsaturated and polyunsaturated fatty acids respectively).

How do we know that the traditional Medi diet is associated with a long lifespan and healthspan?

Shortly after WWll, it was observed that people who ate these types of foods were more likely to live longer and healthier lives. This stimulated research into the diet, in order to better understand this association. Have you heard of "Blue Zones?" These are places around the world where the residents live to age 100 much more frequently than in other parts of the world. Two of these Blue Zones are located in the Mediterranean region, and encompass people who have historically consumed a traditional Medi diet. In fact, the first Blue Zone identified was in Sardinia. Another one in the region is Ikaria, in Greece.

Clinical Research on the Mediterranean Diet

What has this diet been shown to be good for?

That's one of the most impressive things about it. Just about every body system or health condition that has been investigated has fared well on this diet. Which makes sense, right? If a diet is truly good for the body, it's going to look good from whatever angle you look at it.

What do we know about it for the heart and cardiovascular system?

One of the first big studies to be done on this subject took people who had one previous heart attack to see if this diet could help prevent having a second heart attack. They looked to see if people on the Medi diet fared better compared to another group who were simply told to avoid saturated fats and sugars.

The Medi diet group did so much better than the other group, they had to stop the study early. The Medi diet experienced 75% fewer heart attacks in the three-year follow-up. The researchers stopped the study because they deemed it unethical to continue to keep the groups separated.

Next, another group of researchers looked to see if the Medi diet could prevent a heart attack from happening in the first place. They looked at about 7500 individuals at high risk for heart disease. Compared to a control group asked to avoid high-fat foods, the Medi diet group had about a 30% reduced risk of having a heart attack in the 5 year period they studied. And, these people didn't even have the best adherence to the diet, so the real potential of the Medi diet at preventing heart disease could be even greater than what was seen here!

Is the diet good for our metabolism?

Yes. Studies looking into this show a dramatic reduction in metabolic syndrome and diabetes incidence. Metabolism is basically how our body handles proteins, carbs, and fats to both make new tissue and also to break down nutrients for energy. Metabolic syndrome is a cluster of markers basically indicating general dysfunction in metabolism. With it you see insulin resistance, unhealthy blood lipids (i.e., dyslipidemia), hypertension (i.e., high blood pressure), and an increased risk of developing obesity. The prevalence of metabolic syndrome in modern-living societies is between 20% and 30%.

So, we definitely want to avoid metabolic syndrome and diabetes! And the really interesting thing is in some of these large studies, the observed metabolic benefits could not be attributed to weight loss or increased physical activity. The benefits seemed to be tied to aspects of the diet itself.

Do we know anything about the Medi diet in the brain?

Yeah, there are a few exciting things about this diet in the brain. People that stick to this diet over time have less risk of developing dementia and other types of cognitive impairment.

And there's also solid evidence that adhering to this diet helps your brain perform well now. This meta-analysis looked at both young and old adults and saw that a variety of aspects of cognition were improved, especially aspects of memory. And this work showed that you don't have to be from the Mediterranean region in order to experience these brain benefits.

So early work on this dietary pattern showed that the people who ate this way culturally lived a long time. Has there been any other work to show that people live longer on this diet since then? Two different meta-analyses showed that high adherence to the Medi diet pattern was associated with a reduction in all- cause mortality. One specific dietary component of the Medi diet that has been shown to associate with longevity is extra virgin olive oil. Another cool finding, in a study of nurses, showed that higher adherence to a Medi diet elongates telomeres, which are caps at the ends of chromosomes that protect our DNA. That seems to be a good thing for aging well.

What Components Make the Mediterranean Diet So Healthy?

Is the Mediterranean diet healthy because of the specific foods that are being added in, or is it simply because of what is being substituted? Any time you make changes to your diet, you're displacing certain foods that you were eating before. So, with any dietary modification, its effects are from not just what you are now eating, but also what you are now excluding. Interestingly, the benefits of the Medi diet probably aren't solely due to crowding out the bad stuff. It's also the health-promoting compounds that are being added in, like polyphenols, fiber, antioxidants, healthy fats, and so on, that are having a positive effect.

What are polyphenols?

Polyphenols are chemicals found in plants that we eat, like for instance, some of the staples of the diet like red wine, olive oil, and green leafy vegetables. They have a wide range of health- promoting effects and it appears the benefits are dose- dependent - meaning that the higher the polyphenol intake, the greater the benefits for things like lowering blood pressure, raising good cholesterol, and reducing inflammation markers. In fact, one of the reasons why olive oil so strongly associates with a lot of the observed health benefits is because there are over 50 different polyphenols found in olive oil!

Does the Medi diet influence our gut bugs and does it matter?

Gut bugs do all kinds of important things in the body. They shape our immune system, help metabolize nutrients and drugs, and even affect appetite. Because of the higher fiber and nutrients, the Mediterranean diet promotes healthy gut flora. And gut flora even has a positive effect on brain health and cognitive performance.

Really? So then will this diet make me smarter?

Perhaps! The Medi diet is beneficial for the brain in several different ways.

So, these bacteria can send feedback to the brain via a signaling pathway called the gut-brain axis. This can affect how you think and even feel. Pretty amazing. But the diet is also high in nutrients that dampen oxidative stress and chronic inflammation, which keeps the brain healthy. These nutrients also keep our blood vessels healthy so that our vascular system can better deliver nutrients and remove waste as we think.

What role does dietary fat play in the Mediterranean diet?

Decades ago, we thought that dietary fat was just straight-up bad for you and that we should try to minimize it in general. But we now know that it's not so much the total amount of fat in the diet that matters. In fact, some estimates show about 40% of calories come from fats in the Medi diet, and not only that but these healthy fats seem to play a huge role in the observed health benefits. And remember the diet is naturally high in monounsaturated and polyunsaturated fats from things like olive oil, seafood, and nuts.