U of A Researchers Shed New Light on Preventing Diabetes

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Megan Rosa-Caldwell

Small amounts of physical activity may help protect against insulin resistance, a precursor to Type 2 diabetes that can result from a high-fat diet. University of Arkansas researchers describe their findings in an article published June 22 in Experimental Physiology.

The research also casts doubt on the previously held view that increasing the quantity of mitochondria — which are the tiny structures in cells that convert glucose and fats to energy — would help fix some symptoms of a high-fat diet, according to a news release from the Physiological Society based in London. The researchers found that the benefits from physical activity were not affected by the quantity of mitochondria when enhanced experimentally. 

Insulin is a hormone used to control blood sugar levels. High-fat diets contribute to the development of insulin resistance, which is when their muscle, fat and liver cells do not respond properly to insulin and leads to the development of type 2 diabetes. 

Megan E. Rosa-Caldwell, a doctoral student who works with Nicholas P. Greene, an assistant professor of exercise science, found that mice genetically engineered to have higher quantity of mitochondria were not more protected against insulin resistance induced by a high-fat diet. The researchers fed all the mice in the study a diet that mimics Western diets high in fat. The genetically engineered and control mice were further divided into a group that was allowed to exercise, and a sedentary group. 

Their results showed that physical activity, regardless of the amount of mitochondria, offered similar health benefits against insulin resistance. It appears that exercise's ability to help remove damaged cellular materials and enhance the quality of the mitochondria may be more effective for preventing insulin resistance. However, these aspects need to be further tested, the researchers said.

With rates of obesity and Type 2 diabetes continuing to increase, understanding the cellular processes that help or hurt insulin resistance can help scientists and health-care professionals better tailor effective preventive measures such as exercise.

"For now, physical activity is the greatest protection, but further research may enable us to prevent and treat insulin resistance, and subsequent diabetes, more effectively," Rosa-Caldwell said.

Other co-authors of the paper are Jacob Brown, David Lee, Thomas Blackwell, Kyle Turner, Lemuel Brown, Richard Perry, Wesley Haynie and Tyrone Washington. Greene directs the Integrative Muscle Metabolism Laboratory in the College of Education and Health Professions at the U of A.