Metabolic syndrome -- a group of symptoms including diabetes, pre-diabetes, high blood pressure and high cholesterol that increases the risk of heart disease -- is no longer thought to be caused primarily by abdominal fat.
Instead, researchers at Yale University School of Medicine have determined, via new imaging technologies, that insulin resistance in skeletal muscle leads to changes in energy storage, leading to metabolic syndrome.
Insulin resistance, which occurs when the body becomes resistant to the hormone insulin, occurs in skeletal muscle when the muscles are no longer able to make glycogen, a form of stored carbohydrate, from food energy. In turn, insulin resistance in skeletal muscle promotes an increase in fats in the bloodstream, which leads to metabolic syndrome.
Using magnetic resonance imaging techniques, the researchers were able to determine that insulin-sensitive individuals in their study converted carbohydrate energy (from eating a high-carb meal) into glycogen that was stored in the liver and muscle.
Among insulin-resistant individuals, however, the carbohydrate energy was rerouted to liver fat production. The process elevated the participants’ triglycerides in the blood by as much as 60 percent while lowering HDL (good) cholesterol by 20 percent. This occurred even though the participants were young and lean, with no excess of abdominal fat.
More than 50 million Americans suffer from metabolic syndrome, and half of the population is predisposed to it.
The researchers pointed out that there is good news to their findings: insulin resistance in skeletal muscle can be treated with a simple method, exercise.
Proceedings of the National Academy of Sciences July 18, 2007
Science Blog July 16, 2007
The researchers hit the nail on the head when they identified insulin resistance as a key factor in metabolic syndrome, and took it a step further when they correctly pointed out that this devastating syndrome can be reversed with a simple prescription for diet and exercise.
Metabolic syndrome (which used to be called Syndrome X) was thought to be caused primarily by a combination of diet, genetic factors, a sedentary lifestyle and obesity -- particularly if the fat was distributed around the abdomen in a “spare tire” or potbelly.
Now it turns out that even thin people are at risk of this condition, clearly because insulin resistance can be devastating regardless of other risk factors.
Meanwhile, it’s known that people who don’t exercise build dangerous fat around their organs (called visceral fat) -- regardless of whether they appear fat or thin on the outside. Visceral fat contributes to not only insulin resistance but heart disease and metabolic syndrome as well.
Metabolic syndrome is also sometimes referred to as pre-diabetes, which is characterized by insulin resistance and can easily develop into full-blown diabetes if not treated.
The good news here is that to “treat” metabolic syndrome and pre-diabetes (and also type 2 diabetes, for that matter), the prescription is the same: get out there and exercise, and chose foods appropriate for your nutritional type.
When it comes to eating, you’ll want to stay away from any foods that increase your insulin, namely grains and sugars, and of course, processed foods.