Metabolic syndrome

Townsend Letter for Doctors and Patients, May, 2007 by Jule Klotter

Metabolic syndrome, also known as Syndrome X and insulin resistance syndrome, is the label for a group of measurements, associated with cardiovascular disease and diabetes. The defining factors, at this time, are high blood pressure (greater than 130/85 mm Hg), high fasting glucose levels (more than 110 mg/dL), high triglyceride levels (greater than 150 mg/dL), low HDL cholesterol (men -- less than 40 mg/dL; women -- less than 50 mg/dL), and too much abdominal fat (waist circumference greater than 40 inches for men and greater than 35 inches for women). Measuring around the abdomen (parallel to the floor and at the level of the iliac crest) at the end of a normal expiration provides a better indication of metabolic syndrome than body mass index. People with three or more of these factors meet the present criteria for metabolic syndrome.

By bringing these measurements back to more normal levels, people with metabolic syndrome may reduce their risk of developing heart disease, stroke, and diabetes. Physical activity--as little as 30 minutes of moderate exercise, five days/week--and a good diet are the front line for prevention and treatment. A key point in diet recommendations is to reduce the intake of simple sugars and high glycemic carbohydrates that cause a fast rise in blood sugar. High fructose corn syrup, found in many processed foods, may be especially problematic. T. Nakagawa and colleagues at the University of Florida showed that fructose, and not dextrose, increased blood insulin, triglycerides, and uric acid levels in rats. The researchers say that uric acid inhibits nitric oxide bioavailability: "Insulin requires nitric oxide to stimulate glucose uptake."

In a 2005 joint statement, the American Diabetes Association and the European Association for the Study of Diabetes questioned the value of labeling patients with the term "metabolic syndrome." Authors of the paper found "no solid evidence" that "any of the metabolic syndrome health factors contribute more together than they do individually. In other words, the whole is not greater than the sum of its parts.... Each of the health factors mentioned above put people at risk for heart disease and should be treated as such, but the combination of these factors should not be considered, or treated as, a separate disease."

American Diabetes Association. Is the metabolic syndrome really a syndrome? Available at: www.diabetes.org. Accessed February 7, 2007.

Gaulte J. ADA statement-metabolic syndrome not a useful concept any longer. Available at: http://mdredux.blogspot.com/2005/08/ada-statement-metabolic-syndrome-not.html. Accessed February 7, 2007.

Getting tough with metabolic syndrome. Available at: www.postgradmed.com/issues/2004/01_04/metabolic_foldout.pdf. Accessed February 7, 2006.

Holt S. Natural approaches to the metabolic syndrome, syndrome x. Available at: www.power-surge.com/educate/holt_syndromex.htm. Accessed on February 7, 2007.

The metabolic syndrome. JAMA. February 15, 2006; 295(7):850. Available at: http://jama.ama-assn.org/cgi/reprint/295/7/850. Accessed February 7, 2007.

Nakagawa T, Hu H, Zharikov S, et al. A causal role for uric acid in fructose-induced metabolic syndrome (Abstract). Am J Physiol Renal Physiol. 2006 Mar;290(3):F625-31. Available at: www.ncbi.nlm.nih.gov/entrez/. Accessed February 7, 2007.