What’s Up With the Mediterranean Diet?

What cardiologists want you to know

Most of us have heard about the Mediterranean diet, which has generated interest from both the media and the medical community as the gold standard in healthy eating.  But what’s all the fuss about — is this diet really worth all the attention?


The answer is yes, according to Dr. Murray Mittleman, a physician in the CardioVascular Institute, director of the master’s in public health program at Harvard Medical School and director of cardiovascular epidemiological research at BIDMC.  “The Mediterranean diet is a very healthy eating style that has been shown to improve cardiovascular risk factors – even for patients with established heart disorders.”


What is the Mediterranean Diet?


While most healthy diets include produce, whole grains, and fish, the Mediterranean diet and lifestyle offers subtle differences that may reduce the risk for heart disease, while making it easier to stick to healthy eating habits.


According to the American Heart Association, traditional Mediterranean diets have the following characteristics in common:

  • High consumption of fruits, vegetables, beans, nuts and grains
  • Use of olive oil rather than saturated fats like butter
  • Low to moderate consumption of dairy, eggs, fish and poultry
  • Very little red meat
  • Wine in low-to-moderate amounts


The Diet’s “Discovery”


Originating from the culture and traditional foods found in the area bordering the Mediterranean Sea, this diet first drew the attention of the American scientist Ancel Keys, who was stationed in Italy during World War II.  Keys was convinced that middle-aged American men were experiencing heart attacks due to their diets and lifestyles.  After conducting studies in the U.S., he began to work with researchers overseas in the first cross-cultural comparison of males and heart attack risk in what is known as the Seven Countries Study.


Starting in 1958, the Seven Countries Study followed 11,579 men, 40-59 years of age, in four regions of the world (United States, Northern Europe, Southern Europe, and Japan).  This study found that men in Southern Europe were far less likely to experience coronary deaths than those in the U.S. and Northern Europe.  The study also began to identify the eating pattern known as the Mediterranean diet and its protective benefits.


Since then, “additional research has continued to show the beneficial effects of the diet,” said Mittleman. “The Lyon Diet Heart Study, conducted in the 1990s in France, showed that those who followed the Mediterranean Diet for three years had significantly fewer additional heart attacks and a 76 percent reduction in cardiovascular deaths than the control group.”


How Does It Work?


The Mediterranean diet is a combination of many healthy choices that work in tandem to promote good health, according to Mittleman.  “There is a low intake of refined carbs and very little processed food, which is an important distinction that also lowers fat and salt content.  There is more variety in fruit and vegetable consumption, and portions are more controlled.”


Understanding how and why the Mediterranean Diet works involves looking at each of the components that make up this particular style of eating.


Healthy fats


The Mediterranean Diet does not focus on limiting total fat consumption, but it does avoid the use of saturated fats and hydrogenated oils (trans fats), which both contribute to heart disease.



Most of the fat calories in a Mediterranean diet come from “good” or monounsaturated fats, mainly from olive oil, but also from nuts.  “These plant-based fats don’t raise blood cholesterol levels the way saturated fat does,” said Mittleman.  “In fact, monounsaturated fats actually help reduce LDL cholesterol levels when used in place of saturated or trans fats.”



Monounsaturated fats, such as olive oil, contain alpha-linolenic acid, a type of omega-3 fatty acid from plant sources.  Omega-3 fatty acids lower triglycerides, moderate blood pressure, decrease blood clotting, and improve the health of your blood vessels.



Light Protein Sources



Fish is frequently on the menu of the Mediterranean diet, and red meat is rarely served.  Light in calories, fish is a beneficial substitute for meat-heavy Western cuisine, which is higher in unhealthy saturated fat.   In addition, fish such as mackerel, lake trout, herring, sardines, albacore tuna and salmon are rich sources of omega-3 fatty acids.



Other plant-based protein sources, such as beans and nuts, also predominate in this style of eating.  These vegetarian protein sources are also light on saturated fat, helping to keep cholesterol and blood pressure in check.



Plenty of Produce



A wide variety of fruits and vegetables play an important role in the Mediterranean diet, and include fresh salads, greens sautéed in garlic and olive oil, soups and vegetarian pasta dishes.



Fruits, such as melon, often serve as dessert, rather than the sweetened, high-fat concoctions that Western-style dining offers.  Baked sweets are generally reserved for holidays or special occasions.  Fresh produce provides phytonutrients that prevent and repair damage to cells and protect blood vessels.  In addition, the added fiber in the diet slows the release of glucose in the blood stream, which is an important way to help prevent or control diabetes.


A Little Wine


The Mediterranean diet typically includes a small amount of wine.   While red wine has antioxidant properties, the amount, frequency and style of enjoying wine is what makes this an important part of Mediterranean dining, according to Kenneth J. Mukamal, internist and researcher for Beth Israel Deaconess Medical Center.



Mukamel served as lead researcher in a BIDMC study that linked the heart benefits of alcohol to the frequency of drinking.  The study, which investigated 38,000 men over a 12-year period, was published in the New England Journal of Medicine.



“The study confirmed that people who have one drink a day have the lowest rate of heart disease compared with non-drinkers or heavy drinkers,” said Mukamal.  “It doesn’t seem to be the type of alcohol that matters; it’s the frequency.  Having a little bit three-to-seven days a week has the best benefit.  There’s also evidence that alcohol consumed with meals—which is typical in the Mediterranean diet—enhances the benefit, providing a more gradual increase in blood alcohol levels.”


Mukamal cautions that for some people, such as those who have or are at risk for breast cancer or hepatitis C, regular consumption of alcohol may not be advisable.   “It’s a complex mixture of potential risks and benefits, so it’s always worth a discussion with your doctor to be sure that drinking small amounts of alcohol is right for your situation.”


Taking the Mediterranean Route


The incidence of heart disease and deaths in Mediterranean countries is lower than in the United States. But such statistics may not be entirely dependent upon diet.  It’s apparent that the Mediterranean diet is part of a lifestyle.  Exercise, such as walking, is frequent.  Families and friends gather to enjoy meals and each other’s company.  And the pace of living seems less frenetic than in the Western world.


But you don’t have to go to Rome to live as the Romans do.  With some planning and attention to diet and lifestyle, you can bring the flavor and health benefits of the Mediterranean into your own life.


The changes aren’t as severe as you might think.  Here are some steps that can get you moving in the right direction:

  • Use olive oil instead of butter or margarine.
  • Increase servings of fresh veggies and fruits – aim for at least 7 per day.
  • Eat fish and poultry and minimize or eliminate red meat.
  • Aim for several meatless meals each week, incorporating legumes as a protein source when possible.
  • Use fresh herbs and spices to flavor food instead of salt.
  • Avoid foods that are processed, high-fat or contain trans or saturated fat.
  • Have a small glass of wine with dinner, if your doctor agrees.
  • Take a half-hour walk each day.
  • Invite your family and friends to join you!


“The Mediterranean diet is very sustainable and livable,” said Mittleman.   “There’s a lot of variety for your palate and it’s easy to maintain.  And the heart-health benefits will pay you back for a lifetime.”


Posted: January 2013