For years, physicians have been recommending the “Mediterranean” diet to patients with and at risk for cardiovascular disease (CVD). These recommendations have been largely based on small research studies as well as the observation that people from Mediterranean countries have lower rates of heart disease than other Westernized countries. However, a very recent study in the New England Journal of Medicine (NEJM) provides new and compelling evidence that the Mediterranean diet may in fact have a dramatic impact on heart health.
What is the Mediterranean diet? The diet includes a high intake of olive oil, fruit, nuts, vegetables, and cereals, accompanied by moderate amounts of fish and poultry and with limited intake of dairy products, red meat, processed meats, and processed desserts. Wine is consumed in moderation (approximately 1 glass/day) with meals.
In the NEJM study, over 7000 participants without CVD but with major risk factors such as high blood pressure, cholesterol and diabetes were randomized to three different diet groups: the Mediterranean diet supplemented with extra-virgin olive oil, the Mediterranean diet supplemented with extra nuts, and a control, low-fat diet. Unfortunately, the control group subjects (those assigned to a standard low-fat diet), did not really change their diet patterns. So, in effect, they continued to eat the same standard higher-fat diet they had been eating prior to beginning the study. However, the study participants assigned to follow the Mediterranean diet did indeed increase their consumption of certain foods, particularly their assigned supplements (olive oil and nuts, respectively) and to a lesser extent, fish and legumes.
The study was stopped early, after 5 years, because researchers noted such a dramatic effect in the reduction in cardiovascular events in the two Mediterranean diet groups. How dramatic was the effect? The participants in the Mediterranean diet groups demonstrated approximately a 30% reduction in their relative risk of a major cardiovascular event. As always, there are limitations to the study. Given the extra supplements of olive oil and nuts included in the Mediterranean diet, researchers were not able to determine the effect of a diet high in olive oil, fish, legumes, fruits and vegetables but without these extra supplements. Moreover, subjects in the control group did not consume a particularly healthy diet, and therefore the impact of the Mediterranean diet may have been overestimated.
Regardless, though, results from this study indicate that there are sustainable, enjoyable ways to promote cardiovascular health through diet. In fact, the term Mediterranean “diet” is a misnomer in that for many individuals in these geographic areas, it is a consumption lifestyle rather than a particularl diet. Perhaps the easiest rule of thumb to start initiating a switch to a Mediterranean-based dietary pattern is to increase your awareness of the contents of your grocery store shelves. A true Mediterranean diet contains few packaged, processed or pre-prepared foods. Next time you are in the store, observe the high quantity of shelf space dedicated to these types of foods …and avoid them. Pick instead unprocessed foods (fruits, vegetables, non-meat-based sources of protein) and find new combinations and recipes that you find enjoyable. Crack open a bottle of wine and salute!
Reference: Estruch R, Ros E, Salas-Salvadó J, Covas MI, D Pharm, Corella D, Arós F, Gómez-Gracia E, Ruiz-Gutiérrez V, Fiol M, Lapetra J, Lamuela-Raventos RM, Serra-Majem L, Pintó X, Basora J, Muñoz MA, Sorlí JV, Martínez JA, Martínez-González MA; the PREDIMED Study Investigators. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. N Engl J Med. 2013 Feb 25. [Epub ahead of print]