It’s Nuts: Adding Nuts to Mediterranean Diet Zaps Metabolic ProblemsIt’s Nuts: Adding Nuts to Mediterranean Diet Zaps Metabolic Problems

Adding a daily serving of mixed nuts to the traditional Mediterranean diet (which consists of whole grain cereals, vegetables, fruits and olive oil, a moderate intake of fish and alcohol and a low intake of dairy, meats and sweets) is a delicious, natural and effective way to treat metabolic syndrome in older adults who are at high risk for heart disease. That's the conclusion of research just published in the December issue of Archives of Internal Medicine, a journal of the American Medical Association.

Metabolic syndrome, also known as "insulin resistance syndrome" or "syndrome X", is a set of metabolic abnormalities that includes being overweight, having high cholesterol, high blood pressure and high blood glucose levels. According to the American Diabetes Association, metabolic syndrome affects how the body burns calories and uses insulin (which helps the body use or store glucose from food). About one in five overweight people has metabolic syndrome -- and that places them at increased of type 2 diabetes, heart disease, and early death. The new research suggests that adding daily nuts to the Mediterranean style of eating may have a beneficial impact on some of the more dangerous ways metabolic syndrome affects the body, including causing oxygen-related cell damage, resistance to the effects of insulin and chronic inflammation.

For the study, Jordi Salas-Salvadó, M.D., Ph.D., of the University of Rovira i Virgili, Spain, and his team of researchers studied 1,224 participants between the ages of 55 and 80 in the PREDIMED (Prevencion con Dieta Mediterranea) study who were at high risk for cardiovascular disease. The research subjects were randomly assigned to one of three groups. One group received instruction on eating a low-fat diet, another received quarterly education about the Mediterranean diet, which included 1 liter per week of virgin olive oil, and the third group was instructed on eating the Mediterranean diet plus 30 grams per day of mixed nuts.

At the beginning of the study, 61.4 percent of the participants were diagnosed with metabolic syndrome. After a year, 409 participants in the Mediterranean diet plus olive oil group, 411 in the Mediterranean diet plus nuts group and 404 in the control group of low-fat diet advice were again examined for the health problem. The number of participants with metabolic syndrome decreased by 13.7 percent among those in the nut group, 6.7 percent in the olive oil group and only 2 percent in the control group.

Even though the research subjects' weight didn't vary much over the one-year period, the number of people with large waist circumference, high triglycerides or high blood pressure significantly decreased in the Mediterranean diet plus nuts group compared with the others. This suggests that some elements of the diet, principally the nuts, have beneficial effects on pathophysiological characteristics of metabolic syndrome. The Mediterranean diet itself is high in unsaturated fatty acids and the addition of nuts adds beneficial nutrients such as potassium, calcium and magnesium as well as fiber.

"Development of the metabolic syndrome depends on a complex interaction between still largely unknown genetic determinants and environmental factors, including dietary patterns," the authors of the study wrote. "Traditionally, dietary patterns recommended for health have been low-fat, high-carbohydrate diets, which generally are not palatable. The results of the present study show that a non–energy-restricted traditional Mediterranean diet enriched with nuts, which is high in fat, high in unsaturated fat and palatable, is a useful tool in managing the metabolic syndrome." A planned longer follow-up study of the PREDIMED research subjects may provide even more evidence eventually of the cardiovascular benefits of the Mediterranean style of eating, along with nuts.