A study published this week in Science Translational Medicine suggests that binge drinking may be directly linked to an increased risk of type 2 diabetes. The group from the Diabetes, Obesity and Metabolism Institute at the Icahn School of Medicine showed that heavy, sporadic drinking induced insulin resistance throughout the bodies of the rats they tested. Insulin resistance is part of the metabolic syndrome – along with obesity and high blood pressure – which is a set of key risk factors for developing type 2 diabetes, coronary artery disease and stroke.
Until now, it has been difficult to say whether binge drinking causes insulin resistance because this behaviour often occurs together with binge eating. To separate the two, the researchers treated rats with alcohol for three days in order to mimic binge drinking, while a control group was fed the equivalent calories. They found that the alcohol-treated rats had higher blood insulin concentrations than those in the control group, even after their blood alcohol had dropped to undetectable levels. This insulin resistance lasted for up to 54 hours after they had last been given alcohol.
Insulin controls how much glucose is released from the liver and adipose tissues, partly via signalling in the hypothalamus region of the brain. The study found that insulin signalling in this area was suppressed following binge drinking. Protein tyrosine phosphatases, which normally regulate insulin signalling by inactivating the insulin receptor, seem to be responsible for this. The group showed that binging increased expression of these phosphatases in the hypothalamus and that inhibiting their activity protected against the associated insulin resistance.
While we have long known that binge drinking has negative health effects, this study is the first to show a direct link with insulin resistance and could have important epidemiological implications if the processes described also occur in humans.
