Wednesday, March 05, 2008

Is Insulin Resistance A Natural Defense Against Overnutrition?

When we eat, we make glucose available to our cells for energy and other processes. Insulin helps that glucose enter our cells. But when cells reach a certain satiety point, insulin's signaling ability lessens, possibly protecting the cell from an influx of too much glucose. This process may be at the root of insulin resistance.

A study that appeared in the February 21 issue of Nature described a link between the presence of glucose, fats, and other nutrients in the bloodstream ... and the action of an enzyme called O-linked beta-N-acetylglucosamine transferase (OGT). When nutrient levels are high, OGT travels out of the cell nucleus to the cell membrane. There it works to dampen insulin signaling by attaching glucose-containing molecules to key proteins of the intercellular insulin signaling pathway.

Not surprisingly, the particular sugar molecule it attaches is called O-linked beta-N-acetylglucosamine (O-GlcNAc). And the amount of O-GlcNAc is related to how much glucose is in the bloodstream.

Knowing the specific enzymes and sugars involved in insulin resistance can lead to the development of specific drugs that target these molecules. This type of research can also help us to understand how overnutrition can bring about insulin resistance, a condition which often leads to diabetes.

Although drug therapy that targets these molecules may not be available for a while, diet therapy is available today. Learning how to feed our bodies just what they need, but not more than they need, can improve the action of insulin ... reducing the occurrence of insulin resistance and lowering the risk for type 2 diabetes.

For the study:
Phosphoinositide Signalling Links O-Glcnac Transferase To Insulin Resistance

News article (ScienceDaily):
Novel Link Between Excessive Nutrient Levels And Insulin Resistance Uncovered