The Mediterranean Diet: Is It Cardioprotective?

Marita C. Bautista, RN; Marguerite M. Engler, PhD, RN, MS


Prog Cardiovasc Nurs. 2005;20(2):70-76. 

In This Article

The Mediterranean Diet

The traditional diet of the Mediterranean culture has received attention due to increasing scientific evidence demonstrating its protective benefits in reducing overall mortality and CHD events. It is based on the early dietary pattern of populations in Crete, Greece, and southern Italy.[2] There is variability in the Mediterranean diet due to the wide geographical distribution of people in this region, with at least 16 countries bordering the Mediterranean Sea.[4] Cultural, ethnic, religious, economic, and agricultural differences in these regions account for the variation in dietary patterns.[4] The traditional Mediterranean dietary pattern (Figure 1) is characterized by the following: daily consumption of fruits, vegetables, whole grain breads, non-refined cereals, olive oil (the primary source of added fat), and dairy products; moderate weekly consumption of fish, poultry, nuts, potatoes, and eggs; low monthly consumption of red meat; and daily moderate wine consumption.[8]

The traditional Mediterranean dietary pattern. Reprinted with permission from Arch Hellen Med . 1999;16(5):516-524.[8]

The cardioprotective effects of the Mediterranean diet were first considered in the 1950s by Ancel Keys, a nutritionist in Minnesota. Keys conducted the Seven Countries Study, an epidemiological investigation that examined the association between dietary intake (primarily fat content) and cardiovascular (CV) health in different populations.[9] Keys noted that the mortality rate from CHD and all other causes was significantly lower in Mediterranean regions (particularly in the Greek island of Crete) compared with the northern European regions and the United States.[10] Subsequent studies have focused on the effect of a high intake of olive oil and the overall composition of the Mediterranean diet on CV health.[11] Based on the scientific evidence, the AHA issued a scientific advisory indicating that a Mediterranean-style diet has positive effects on CV disease.[4] Current dietary guidelines could be enhanced by incorporating components of the Mediterranean diet within current AHA recommendations.[4]

The purpose of this paper is to present the clinical trial evidence supporting the role of the Mediterranean diet in CV health with a focus on the physiological effects of omega-3 fatty acids. Implications for clinical practice and future research are also discussed.

The Mediterranean dietary plan is characterized as a "whole-diet approach."[12] The scientific basis for the beneficial CV effects of this diet is not fully understood. For example, it is not known whether individual nutrients confer the benefits or if the accumulation of multiple nutrients accounts for the CV effects. The Mediterranean diet is rich in a variety of vitamins and nutrients, including beta carotene, vitamins C and E, polyphenols, fiber, antioxidants, and many important minerals.[13]

The distribution of the different types of fats in the Mediterranean diet is significant. Although the fat content may be high (comprising up to approximately 40% of total energy intake), the Mediterranean diet emphasizes the consumption of two types of fat (namely, omega-3 polyunsaturated and monounsaturated fatty acids) that have been shown to exert cardioprotective effects.[14,15] The diet is low in saturated fat and has a monounsaturated-to-saturated fat ratio of two.[15] It also has a balanced ratio of omega-6:omega-3 essential fatty acids of 1-2:1, instead of the 15:1 ratio in western and northern Europe and the 16.7:1 ratio in the United States.[15] In addition, the Mediterranean diet emphasizes consumption of natural, whole foods and the avoidance of processed foods high in unhealthy fats such as trans-fatty acids.[6]


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