The Effect of a Mediterranean Diet Supplemented With Nuts on Metabolic Syndrome

A Mediterranean style diet is high in fruits, vegetables, and fish and low in red meat. This diet does not focus on low fat but does emphasize choosing healthier fats such as monounsaturated fats. These fats are found in foods like nuts and olive oil. This diet is hoped to be beneficial for people with heart disease or risk of heart disease.

The metabolic syndrome is a grouping of risk factors in one person. Abdominal obesity, high cholesterol and blood pressure, and insulin resistance are some of the factors. This syndrome significantly increases the risk of heart disease and diabetes and is thought to be at least partially caused by lifestyle choices like diet.

Researchers in Spain reviewed the effect of slightly altered Mediterranean diets in people with heart disease risk factors. The study, published in the Archives of Internal Medicine, found that the Mediterranean diet with added nuts was the most effective in decreasing risk factors.

About the Study

The randomized trial followed 1,224 participants for one year. The participants all had high risk for cardiovascular disease and 61% of them had metabolic syndrome. They were randomly divided into one of three groups. Each group had quarterly education sessions. One group was advised to follow a Mediterranean diet that emphasized 1liter/week of olive oil (about 1 quart). A second group was advised to follow a Mediterranean diet with a goal of 30 grams/day (about 1 ounce) of mixed nuts. And a third group was a control group on a low-fat diet. After one year, the decrease in prevalence of metabolic syndrome was:

  • 13.7% for the Mediterranean diet plus nuts
  • 6.7% for the Mediterranean diet plus olive oil
  • 2% for the low-fat group

How Does This Affect You?

The Mediterranean diet may not suit all tastes but there are important elements that can be included in any diet. In general, a heart healthy diet is high in fruits and vegetables and low in saturated fats. More recent studies also suggest that replacing unhealthy fats in our diets with monounsaturated fats may improve heart disease risk levels. Nuts are a good source of monounsaturated fats.

Lifestyle choices can play an important role in preventing or managing metabolic syndrome. Talk to a registered dietitian about making healthier choices in your diet.


American Dietetic Association
American Heart Association


Salas-Salvado J, Fernandez-Ballart J, Ros E, et al. Effect of a Mediterranean diet supplemented with nuts on metabolic syndrome status: one-year results of the PREDIMED randomized trial. Arch Intern Med . 2008 Dec 8;168(22):2449-58.
Last reviewed February 2009 by Larissa J. Lucas, MD

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