CBS prof examines metabolic reasons why people become overweight and how extra weight can lead to Type 2 diabetes
BY KAYLA DUFFIELD SPARK PROGRAM
U of G researchers are working to better understand how exercise and adrenalin can burn fat and help curb the growing epidemic of obesity and Type 2 diabetes in Canada.
“The beautiful thing about exercise,” says Prof. Lawrence Spriet, Human Health and Nutritional Sciences, “is that it helps muscles get better at using fat.”
Spriet is looking at the metabolic reasons why people become overweight and how extra weight can lead to Type 2 diabetes. He's taking muscle samples from three groups of middle-aged men (obese, Type 2 diabetics and lean) to observe what's happening inside their muscles and to understand how the body uses fat and carbohydrates.
“The advantage of our research is that we are actually taking measurements inside the muscles,” says Spriet. “Less invasive techniques are less accurate.”
Healthy people readily metabolize fat and carbohydrates into energy, but Type 2 diabetics do not, he says. They become resistant to insulin, which prevents the body from using glucose or sugar, the basic fuel of cells. Normally, insulin helps take glucose from the blood and feeds it to the cells, but in diabetics, glucose accumulates in the blood. Over the long term, excessive sugar can hurt the eyes, kidneys, nerves and heart, and cause excessive thirst, hunger, urination and fatigue.
Unable to use sugar, cells must rely on fat for energy (taking it from the blood). But this is also a flawed process in diabetics, says Spriet, because the fat accumulates in muscle.
An associated fat burner in muscle tissue is the enzyme hormone-sensitive lipase, which helps unlock the fat that is stored in the muscle for fuel. He is conducting eight-week cycling programs to test how lipase is affected by exercise. Moderate exercise or adrenalin usually turns it on, but inactivity — common to obese people or Type 2 diabetics — turns the fat-burning enzyme off. Through his research, Spriet hopes to prove moderate exercise will activate the lipase enzyme, promoting active living.
Also involved in this research were Rebecca Tunstall and Jane Rutherford of the Department of Human Health and Nutritional Sciences. Funding has been provided by the Canadian Institutes of Health Research.
