Literature Review: Mediterranean Diet & Cardiovascular Health

Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. NEJM, 2013 Apr 4; 368(14): 1,279–90.

Abstract

This was a randomized trial to evaluate the effect of the Mediterranean diet in the primary prevention of cardiovascular events. Study participants were age 55–80. They had no known cardiovascular disease at the start of the study, but were at high cardiovascular risk, with risk factors such as type 2 diabetes mellitus, smoking, hypertension, elevated low-density lipoprotein cholesterol levels, low high-density lipoprotein cholesterol levels, overweight or obesity, or a family history of premature coronary heart disease. Participants were randomly assigned to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a low-fat diet. The primary endpoint was the incidence of myocardial infarction, stroke or death from cardiovascular causes. The trial was stopped early, after 4.8 years, because a significant difference in groups was already found. 7,447 persons were enrolled. A primary endpoint event occurred in 288: 96 in the group with the Mediterranean diet with extra-virgin olive oil, 83 in the group with the Mediterranean diet with nuts, and 109 in the group with the low-fat diet. The Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events by 30%.

Comment

This study provides useful advice for our patients—and us. There is a high rate of cardiovascular risk factors in the EMS community. Approximately three-quarters of emergency responders (fire, law enforcement, EMS) were reported to have prehypertension or hypertension in a nationwide review,¹ and 77% of emergency responder recruits in Massachusetts were found in one survey to be overweight or obese.²

The Mediterranean diet is based on the traditional dietary patterns of southern Italy, Greece and Spain. It consists of grains, legumes, nuts, vegetables and fruits; olive oil as the principal source of fat; fish and poultry (avoiding red and processed meats); and moderate alcohol, typically red wine with meals. It is believed to be beneficial because it is low in saturated fat and high in monounsaturated fat and dietary fiber. The Mediterranean diet has long been believed to have health benefits, and this study shows that it may substantially lower the incidence of heart attacks and strokes—even when compared to a low-fat diet.

There are some limitations. First, the participants in the low-fat diet group didn’t follow it very closely. This is a common observation; many people find low-fat diets unappealing. And second, the most substantial difference between the groups was the amount of extra-virgin olive oil (1 liter/week) and nuts (30 g/day) given those on the Mediterranean diet. It’s not clear how much of the reduction in cardiovascular events was due to olive oil or nut consumption.

More studies will follow, but for now, especially taken in the context of numerous previous studies, it appears the Mediterranean diet (online at www.predimed.org) can reduce the incidence of heart attacks and strokes. We should all consider adopting this diet.

References

1. Kales SN, Tsismenakis AJ, Zhang C, Soteriades ES. Blood pressure in firefighters, police officers, and other emergency responders. Am J Hypertens, 2009 Jan; 22(1): 11–20

2. Tsismenakis AJ, Christophi CA, Burress JW, Kinney AM, Kim M, Kales SN. The obesity epidemic and future emergency responders. Obesity (Silver Spring), 2009 Aug; 17(8): 1,648–50.

Angelo Salvucci, Jr., MD, FACEP, is medical director for the Santa Barbara County and Ventura County (CA) EMS agencies and a member of the EMS World editorial advisory board.