MedDiet

When we talk about the MedDiet we are talking about a sensible omnivore diet in which monounsaturated fats are emphasized, and saturated fats and simple carbohydrates are deemphasized. 

There is a large body of strong scientific evidence to support the health benefits of the MedDiet. The MedDiet is one of several similar diets that also have been shown to promote health benefits such as the MIND (Mediterranean-DASH diet Intervention for Neurodegenerative Delay), Baltic Sea Diet, Healthy Eating Index (HEI), and the Okinawa Diet. All of these diets have in common that they are plant forward, which means that a large component of the diet are vegetables and fruit. A good MedDiet consists of vegetables in the form of salads, roasted and steamed vegetables, fish, olive oil, nuts and seeds, whole grains, some poultry and other meats, some cheese and dairy, fruit and a small amount of wine can be consumed if enjoyed. 

The idea of a Mediterranean Diet started in Italy in 1614 when Giacomo Castelvetro wrote the book, “The Fruit, Herbs and Vegetables of Italy”. In 1950 Elizabeth David, wrote the book, “A Book of Mediterranean Food.” The father of the modern notion of the MedDiet was Ancel Keys who ran the Seven Countries Study. In 1993 Harvard School of Public Health in conjunction with the World Health Organization created the MedDiet pyramid. In 1994 the landmark Lyon Diet-Heart Study was performed. In 1995 the MedDiet Index was introduced by Trichopoulou et al in Greece.  In 2010 the MedDiet was declared an intangible Cultural Heritage of Humanity by UNESCO. In 2013 another landmark study, The PREDIMED Trial was performed.

Ancel Keys was a physiologist and epidemiologist from the University of Minnesota who first coined the term, The Mediterranean Diet. He was concerned with the rapidly increasing rates of coronary artery disease in the US. In the 1950’s he conducted the Seven Countries Study, which enrolled 13,000 me from 7 countries ( Italy, Greece, Japan, Finland, the former Yugoslavia, the Netherlands, and the United States). He discovered that the MedDiet was beneficial for cardiovascular risk, and specifically that a diet high in monounsaturated fats (MUFA) as opposed to saturated fatty Acids (SFA) was particularly beneficial for heart health. He also discovered that a diet high in fats (up to 40% of calories from fats) was healthful as long as the MUFA:SFA ratio was elevated.

The first landmark trial showing the heart benefits of the MedDiet was The French Lyon Diet Heart Study. The study was performed between 1988 and 1992 and enrolled 605 patients with a history of a previous heart attack s a secondary prevention trial. The Study group was placed on a MedDiet while the control group was placed on the American Heart Association diet of the time. The study was stopped early because at 27 months there was a 73% reduction in subsequent heart attacks and a 70% reduction in total mortality.

Another landmark trial was The PREDIMED Trial conducted in 2013 in Spain. 7447 participants with elevated cardiovascular risk were enrolled and randomized to 1 of 3 diets: a MedDiet with Extra Virgin Olive Oil (EVOO), a MedDiet with mixed nuts, and a control standard diet. This trial was also stopped early because of a 30% reduction in heart attacks, strokes and cardiovascular deaths. One of he purported benefits of the MedDiet is the beneficial effects of phytonutrients, polyphenols and flavonoids that are richly concentrated in a MedDiet. The PREDIMED Trial showed that in those participants with high urinary excretion of polyphenols had significantly decreased inflammatory biomarkers. In addition, the MedDiet participants had lower blood pressure, higher levels of HDL (“good”) cholesterol, and most importantly genes that are responsible for atherosclerosis formation were turned off in the MedDiet group.

The consumption of alcohol is frequently brought up when discussing the MedDiet. The concept that wine consumption is a requisite part of the MedDiet is no longer supported by the data. Any amount of alcohol consumption will increase overall cancer risk, and alcohol does not decrease cardiovascular risk as was sometimes stated in the past. Alcohol is a toxic, psychoactive substance and dependency-producing substance that is classified as a Group1 carcinogen by the International Agency for Research on Cancer – this is in the same class as asbestos, radiation and tobacco. Therefore, if you enjoy alcohol then your consumption should be 7 or less drinks per week. If you do not consume alcohol you do not need to consume wine or alcohol to achieve the health benefits of the MedDiet.

Dairy products are usually not emphasized in the MedDiet. However, many people living in MedDiet geographical areas like Italy and Greece do consume dairy products. In particular, as our awareness of the importance of the microorganisms that reside in our bodies (the microbiome), fermented dairy and dairy that contain live cultures are felt to be an important adjunct to the MedDiet in small quantities. In fact, a meta-analysis has shown significant reductions in stroke incidence with dairy consumption.

Nutritional research surrounding egg consumption has been contradictory at best. Eggs are very nutrient-rich, however, eggs do contain cholesterol. A large study of over 500,000 adults in China found that 1 egg per day lowered cardiovascular risk. Many other studies support similar findings. Therefore, the current recommendation is 4-7 egg yolks per week and egg whites ad libitum.

In conclusion, there is a large body of evidence that a MedDiet is healthful in general and particularly healthful for cardiovascular health. No other dietary pattern of eating has been studied as extensively as the MedDiet. The American Heart Association has proposed Life’s Simple 7 as risk factors for heart disease and diet is the leading factor. The other risk factors are body weight, physical activity, blood cholesterol level, blood pressure, fasting blood sugar level, and being a nonsmoker. Sleep has recently been added to make it Life’s Simple 8.

The main characteristic of the MedDiet is a plant forward diet with low consumption of meat and meat products, low consumption of processed meats, butter, ice creams and refined carbohydrates. It is a high MUFA diet and low in SFA. Liberal consumption of olive oil (EVOO), vegetables, fruit, legumes, nuts, seeds and unrefined whole grains. An important source of animal protein is fish. The MedDiet is naturally high in phytonutrients, fiber, polyphenols antioxidants which all work together to reduce inflammation and the risk of cardiovascular disease and other chronic diseases such as dementia, Alzheimer’s Disease and cancer.