(Food-Beverage-News.Com, April 17, 2013 ) San Francisco, CA -- The Life Science Institute researcher at the University of Michigan have concluded their study of a long-held belief that whitening of skeletal muscle in diabetes is harmful to an individual.
It turns out that the white muscle that increases with resistance training, age, and diabetes helps keep the blood sugar in check, according to the results.
In addition, the insights from the molecular pathways involved within the phenomenon that were identified in the study may help point the way to drugs that can target obesity and metabolic disease.
"We wanted to figure out the relationship between muscle types and body metabolism, how the muscles were made, and also what kind of influence they have on diseases like type 2 diabetes," said Jiandie Lin, Life Sciences Institute faculty member and associate professor at the U-M Medical School.
The findings of Lin's research will be published in Nature Medicine. Much like poultry having light and dark meat, mammals have a range of muscles that are red, white, or in between. Red muscle, which retains its color in part due to the mitochondria involved, is cultivated in individuals that engage in endurance training. White is known for being more apt to quick-twitch muscle development, like weightlifting.
. "Most people are in the middle and have a mix of red and white," Lin said.
When an individual exercises, nerves signal muscles to contract, and those muscles need energy. The body responds to lifting big weights by enacting white muscles, which utilize glycogen in order to generate adenosine triphosphate energy. While the process can produce power, it can not sustain the power for long. Conversely, if the brain wants a slow and steady burn of less powerful action (relatively speaking) it can use red muscles which primarily use oxidation instead of glycogen breakdown to generate ATP.
People with diabetes tend to see whitening of a mix of muscles that otherwise might not be as such.
"For a long time, the red-to-white shift was thought to make muscle less responsive to insulin, a hormone that lowers blood sugar," Lin said. "But this idea is far from proven. You lose red muscle when you age or develop diabetes, but is that really the culprit?"
