The term “diabetes” is actually associated with several medical conditions that have some similarities in symptoms and clinical treatment but are different in their cause. Type 1 diabetes is an auto-immune disease; in other words, the immune system of the body attacks the insulin-producing cells (called beta-cells) and kills them, leading to inability to produce insulin. Type 2 diabetes usually develops in adults and is the result of both inability of the body to respond to insulin and insufficient insulin secretion to overcome this. Currently, about 90% of all people with diabetes have type 2. Gestational diabetes develops during pregnancy and is temporary, but can predict later development of type 2 diabetes. Finally, MODY (maturity-onset diabetes of the young) is caused by specific genetic mutations and generally runs in families. As the name suggests, it develops in young adults although there is a lot of variability depending on which gene is mutated. MODY is a small fraction of the total cases of diabetes.
Genetics plays a roll in all forms of diabetes but environmental triggers are thought to precipitate the actual disease. Children and teenagers generally develop type 1 diabetes and require insulin replacement to live. There are many ongoing studies to understand what the triggers are, but may include viral infections or certain nutrients. The triggers cause a response in the body that makes its immune system is being attacked, which causes influx of immune cells into the pancreas and the resultant attack on beta-cells. Factors that increase the risk of type 2 diabetes include increasing age, overweight, sedentary lifestyle and other factors also associated with cardiovascular disease such as high blood pressure and high cholesterol. A state of chronic inflammation may exist for several years that results in the main insulin-sensitive tissues of the body (the skeletal muscle, fat and liver) to become less sensitive, thus stressing the beta-cells to produce more insulin. While some people successfully increase their insulin, others become insulin-insufficient, leading to high blood sugar and diabetes diagnosis. This generally occurs in middle-aged and older people. About one-quarter of people over the age of 70 are type 2 diabetic. Treatment includes a healthy diet, physical activity, drugs and sometimes insulin injection.
The Why? is the hardest to understand for both type 1 and type 2 diabetes. Scientists are investigating many hypotheses, trying to learn about how the genetics and environment interact and how to prevent and better treat these diseases. Rhonda and Cathy work in the Alberta Diabetes Institute, which has teams of researchers working on various aspects of diabetes, such as the immune system, beta-cell function, nutritional and physical activity programs, diabetes complications, diabetes surveillance, drug treatment and islet transplantation. Of course, Canada is famous for being the country in which the biggest breakthrough in diabetes research, ever, took place – the discovery of insulin by Banting, MacLeod, Collip and Best in 1921. Before that discovery, type 1 diabetes caused death within a few months or years because of the body’s inability to assimilate calories from glucose and fat. However, more than 90 years later, diabetes is not cured.
In previous blogs, we’ve highlighted research done by Rhonda and Cathy. In order to highlight the diversity of research going on at the Alberta Diabetes Institute, we’d like to mention a couple of other interesting research projects related to nutrition and diabetes. Dr. Donna Vine is interested in how nutrition can be used to improve diabetes-and cardiovascular disease-related risk factors such as elevated cholesterol. In a publication in the British Journal of Nutrition, she and co-authors reported that rats with elevated cholesterol which were fed omega-3 fats from fish oil for 16 weeks had reduced cholesterol and heart damage compared with control rats. These omega-3 fatty acids are in high abundance in fatty fish but here on the prairies we grow flax seeds, which are also an important source. Dr. Carla Prado is interested in how body composition (the relative amounts of muscle and fat tissues) is altered by different health conditions. She has shown that even for people with the same body weight, the proportions of muscle and fatty tissue can vary substantially. This work was recently published in the American Journal of Clinical Nutrition. How these variations in body composition may affect overall metabolism, the response to chemotherapy in cancer, and quality of life are just some of the questions she is attempting to answer.
Diabetes research continues to be a strength of biomedical research in Canada. For more information about foundations and associations that fund diabetes research visit the Alberta Diabetes Foundation (http://albertadiabetesfoundation.com) or the Canadian Diabetes Association (http://www.diabetes.ca).