What Causes Type 2 Diabetes?
Insulin resistance and high levels of insulin and lipids all precede the development of metabolic dysfunction. Which metabolic factor is to blame?
Type 2 diabetes is a multifactorial metabolic disease.1 Obesity, elevated levels of lipids and insulin in the blood, and insulin resistance all accompany the elevated blood glucose that defines diabetes. (Diabetes is defined as fasting blood glucose concentrations above 7 millimolar (mM), or above 11 mM two hours after ingestion of 75 grams of glucose.) But while researchers have made much progress in understanding these components of the metabolic dysfunction, one major question remains: What serves as the primary driver of disease?
Lifestyle choices characterized by inactivity have been postulated as one possible cause. Researchers have also pointed the finger at nutrition, postulating that poor food choices can contribute to metabolic disease. However, there is thus far weak support for these hypotheses. Changing to a healthy diet typically does not result in significant weight loss or the resolution of metabolic dysfunction, and it is rare to reverse obesity or diabetes through increased exercise. Furthermore, there does not appear to be a strong relationship between body-mass index (BMI) and activity level, though exercise clearly has many other health benefits.
With such macroscale factors unable to explain most cases of obesity and diabetes, scientists have looked to molecular mechanisms for answers. There are at least 40 genetic mutations known to be associated with type 2 diabetes. These genes tend to be involved in the Continue reading