Insulin resistance is responsible for something called the metabolic syndrome, also known as syndrome x. In the metabolic syndrome, the individual tends to have high cholesterol with low HDL (the “good” cholesterol) and low LDL (the “bad” cholesterol), and high triglycerides. One of the big problems caused by insulin resistance is obesity. People who are insulin resistant tend to be overweight (especially carrying weight around the abdomen) and may have high blood pressure.

One other aspect of the metabolic syndrome is inflammation and endothelial (lining of the blood vessels) function. In other words, high cholesterol (especially accompanied by high LDL) is a risk factor for heart disease. Inflammation enables plaquing (arteriosclerosis) to occur. The function of the lining of the blood vessels is needed to protect against arteriosclerosis.

Research appearing in the Journal of the American Medical Association (2004;292:1440-1446) indicates that the Mediterranean diet may protect the blood vessel lining and reduce inflammation. It was a randomized, single-blind trial conducted for 2 ½ years with 180 subjects (99 men and 81 women) with the metabolic syndrome. The subjects were divided into two groups, with one group being instructed to follow the Mediterranean diet for two years.

The group following the diet had lower c-reactive protein and interleukins 6 (IL-6), 7 (IL-7), and 18 (IL-18)—these are chemicals whose presence indicate inflammation. The endothelial (blood vessel lining) improved in the group following the diet. The group following the diet even had improvement in insulin resistance; 40 patients in that group still had features of the metabolic syndrome, compared with 78 patients in the control group.