Mediterranean diet graphic (1500 x 1080 px)

It’s funny how seemingly trivial events lie dormant in our minds, undisturbed for decades until they pop up totally unexpectedly. I was reading a paper on the benefits of the Mediterranean diet when, out of nowhere, surfaced a memory into my consciousness.

I was maybe five or six years old and an avid listener of a children’s program of radio plays. One of them told of a little boy, his name was Avrum, who fervently wished to be twice as big and strong as he was. And so, one day a deep voice boomed down on him, “Eat grass! Eat grass!” The little boy, finding grass quite unpalatable, asked the Voice if it would be OK to eat green veggies instead, although he despised them just as much. Permission was granted and little Avrum ate them every single day. Lo and behold, as the years passed he indeed grew twice as big and strong as he had been.

The modern and more adult story is that the Mediterranean diet will make us healthier and live longer. Is there any truth to it, or is it as illusory as the radio play?

 

First, what is the Mediterranean diet?

If you’ve read the various reports on the Mediterranean diet, you realize that definitions vary widely. Are nuts included? Some studies include them, others don’t.

Olive oil is in it, but how much should we consume? In Greece, the salads are drenched in oil; in Italy, a lot less; and in France, quite sparingly.

Fancy raw mixed nuts Photo credit: Wikimedia via Ragesoss CC by SA 3.0
Photo credit: Wikimedia | via Ragesoss | CC by SA 3.0

How about beans? In the Middle East, lots are eaten—think hummus. In France, hardly any. In the Middle East, sweets are moderately consumed; in Turkey and in Greece, honey-dripping Baklava is practically a national symbol.

The fact of the matter is that the Mediterranean diet is a Western construct. There really is no such thing as a unified “Mediterranean cuisine.” But at the same time, we seem to know what we mean when we use the term.

Overall, the traditional Mediterranean diet is characterized by a high intake of olive oil, fruit, nuts, vegetables, and cereals; a moderate intake of fish and poultry; a low intake of dairy products, red meat, processed meats, and sweets; and wine consumed in moderation with meals.

So now that we have a more or less common understanding of what we mean by Mediterranean diet, what is the evidence that it is really good for us?

 

Impact on cardiovascular health

There have been many studies on the impact of the Mediterranean diet on heart disease, many of them poorly designed or poorly executed until one published in the New England Journal of Medicine settled the matter.

Ramon Estruch, Ph.D and his colleagues at the University of Barcelona randomly assigned 7,447 people in Spain who were overweight, smokers, or had diabetes or other risk factors for heart disease to follow the Mediterranean diet or a low-fat one. The subjects were randomly assigned to one of three diets: A Mediterranean diet supplemented with at least four tablespoons/day of extra virgin olive oil, a Mediterranean diet supplemented with an ounce/day of mixed nuts (almonds, walnuts, and hazelnuts), or a low-fat diet. Importantly, the researchers followed end points that ultimately are the important ones: heart attacks, strokes, and death, and not the usual secondary markers such as hypertension or cholesterol levels.

The Mediterranean diet consisted of at least three servings a day of fruits and, at least, two servings of vegetables. Participants were to eat fish and legumes, which include beans, peas, and lentils, at least three times a week. They were told to eat white meat instead of red. The participants who were accustomed to drinking were advised to have at least seven glasses of wine a week with meals.

The results were startling. Compared with the group on the low-fat diet, the 2 groups on the Mediterranean diet had a 30% reduction in heart attacks and stroke (from 6.5% to 4.5%) over a period of 5 years. In fact, the study had to be terminated early, at about 5 years, because the results were so significant it became unethical to continue with the low-fat group.

As an aside, the low-fat diet was so unpalatable that the investigators had to allow this group to follow the usual modern diet with its regular consumption of red meat, sodas, and commercial baked goods.

So, at long last, we have a study that uses a rigorous research design (prospective, randomized, and a large sample size) that shows Mediterranean diets reduce the risk of heart disease. It is truly a triumph.

 

Mediterranean diet and the brain

Fresh salmon steak by freefoodphotos.com is licensed under a Creative Commons Attribution 3.0 Unported License.
Fresh salmon steak | freefoodphotos.com | CC BY 3.0

A presentation at the 67 annual meeting of the American Academy of Neurology, 2015, reported on a large cross-sectional study by investigators at Columbia University in New York looking at the effect of the Mediterranean diet on brain volume in an elderly population.

The researchers used neuroimaging (MRI) to document brain volume, cortical thickness, total gray matter volume and total white matter volume. They found that individuals with higher Mediterranean diet adherence scores (5 to 9 on a scale of 0-9) had larger total brain volumes, total gray matter volume, and total white matter volume compared with those with lower Mediterranean Diet adherence scores (0 to 4). The differences were statistically significant.

The results of this study suggest that this type of diet has the potential to prevent brain atrophy and, by extension, preserve cognition in the elderly.

Further analysis of the 9 food components revealed that higher fish consumption (minimum of 3 times a week) was associated with larger total gray matter volume. Lower meat intake was associated with both larger total brain volume and total gray matter volume. Higher fish intake was associated with higher cortical thickness.

So there you have it. Hard data, indisputable evidence—what more can you wish for? With all these benefits for heart and brain, wouldn’t you like to know if lower mortality and improved cognitive functions can translate into better quality of life?

 

Longevity

And, here is the big surprise. The Mediterranean diet not only improves the quality of life, it actively increases longevity.

Telomeres. Photo credit: Flicker (CC BY-SA 2.0)
Photo credit: Flicker | CC BY-SA 2.0

An analysis of the Nurses Health Study published in the British Medical Journal showed that adherence to the Mediterranean Diet protected telomeres and reduced their shortening. Telomeres are repetitive DNA sequences at the ends of chromosomes that stabilize the chromosome and progressively shorten with age. Shorter telomeres are associated with shorter life expectancy and greater risk for age-related diseases.

Obesity, cigarette smoking, and other lifestyle factors have been linked to shorter telomere length. Oxidative stress and inflammation speed up telomere shortening. Fish, fruits, vegetables, olive oil, and nuts—key components of the Mediterranean diet—have well-known antioxidant and anti-inflammatory effects.

In a statement to Medscape Medical News, the lead investigator, Immaculata De Vivo, MPH, Ph.D., said:

“The health benefits of greater adherence to the Mediterranean diet—reduction of overall mortality, increased longevity and reduced incidence of chronic diseases, especially major cardiovascular diseases—have been consistently demonstrated. Our results further support the health benefits of adherence to the Mediterranean diet and provide some insight into the underlying physiologic mechanism behind this association. Following a diet closer to the Mediterranean diet can prevent accelerated telomere shortening.”

 

The take-home lessons

It is rare that nutritional studies are based on solid experimentation. This is not because nutrition scientists are sloppy or incompetent. By their very nature, such studies are devilishly difficult.

But, here, we cited some excellent studies showing that adhering to the Mediterranean diet indeed has health benefits. In fact, the benefits are greater than any drug aimed at improving health and longevity.

It seems that vegetables, fruits, and nuts have their greatest benefit on the health of the cardiovascular system and on longevity, whereas fish consumption is the main factor in maintenance of cognitive function.

Amazing. No supplements, no drugs, just plain ole wholesome food. Inevitably, industry has tried to cash in with supplements derived from this diet, such as fish oil, fiber pills, antioxidants, vitamins, you name it. Not only is it unnecessary, it is useless. Evidence is emerging that single components of food don’t work solo—they work together, synergistically.

So, here is my prescription: Instead of popping pills to get healthy, just relax after work, have a glass of wine or two, a fresh salad with garbanzo beans, and salmon cooked to perfection.

Be healthy, my friends.

Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.

34 COMMENTS

  1. Fantastic article I just discovered. There are so many diets it is confusing as a lay person to know what to do. CSIRO, 5:2, pritikin, ornish, intermittent fasting and so on. Is there a diet that helps reverse arteriosclerosis and atherosclerosis? Diet and lieftyle of centenarians should be a clue as to who lives Longest and why. How does the data on the ling lived people line up with the Mediterranean diet?

LEAVE A REPLY

Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.