In 2017, the landmark Diabetes Remission Clinical Trial (DiRECT) revealed that type 2 diabetes can be reversed in some adults by following an intensive weight management programme, but no-one knew why. Now, new research being presented at this year's European Association for the Study of Diabetes (EASD) Annual Meeting in Berlin, Germany (1-5 October) suggests that remission is dependent on whether insulin-producing beta cells in the pancreas are able to recover and function normally.
The finding challenges current medical consensus that beta-cell function is irreversibly lost in people with type 2 diabetes.
The study led by Professor Roy Taylor from Newcastle University in the UK provides further evidence that losing fat from around the liver and pancreas is key to putting type 2 diabetes into remission, but suggests that remission can only be achieved if it results in improved function of pancreatic beta cells so they can restart their insulin production. Insulin is a hormone produced by beta cells in the pancreas that helps glucose in the blood enter cells in the muscle, fat, and liver to be used as energy.
The DiRECT trial included 298 adults age 20-65 years who had been diagnosed with type 2 diabetes in the past 6 years. The study, published in The Lancet in 2017, examined whether a new weight management programme consisting of a low-calorie diet (825-853 kcal/day for 3-5months), followed by reintroduction of healthy food, and long-term support to maintain weight loss. Results showed that nearly half of the participants (46%) following the weight management programme achieved diabetes remission at 1 year compared, compared with six (4%) in the control group.
In this new study, Professor Taylor and colleagues investigated exactly how weight loss can put type 2 diabetes into remission and why it works for some people and not for others. They examined fat content in the liver and pancreas, and beta-cell function in a subset of 58 participants from DiRECT--including 40 responders (people in remission) and 18 non-responders (people not in remission) over 12 months. The responders had been living with type 2 diabetes for less time than non-responders (average of 2.7 years vs. 3.8 years).
Over the study period, both groups lost a similar amount of weight (16.2 kg for responders vs. 13.4 kg for non-responders), leading to similar reductions in fat content in the liver and pancreas and average triglyceride concentrations.
However, only the responders showed early and sustained improvement in beta-cell function. After losing weight, the beta cells of people in remission started to work properly again, but there was no change in the amount of insulin being made by non-responders.
"Our findings suggest that the longer someone has lived with type 2 diabetes, the less likely the function of their beta cell is likely to improve", says Professor Taylor. "The clinical message is clear: the new effective weight loss approach should be advised for all with type 2 diabetes, especially at the time of diagnosis".
The authors acknowledge several limitations including that most participants were white and British, so the results might have less generalisability to other racial and ethnic groups, who tend to develop diabetes with less weight gain. They also note that the participants were only evaluated for 12 months, and longer-term follow-up is underway.