Articles in 2019

Pancreatic islets, which are critical for glucose homeostasis, are endocrine microorgans embedded in the exocrine pancreas; their location has often limited studying their function. In 2019, advances in islet biology were achieved with new technologies extending findings from several decades ago and with conceptual advances built on findings from other fields.

Bariatric surgery results in sustained weight loss and improvement in many obesity-related comorbidities. However, the effects of bariatric surgery on long-term mental health are less clear. A recent longitudinal cohort study shows that patients undergoing bariatric surgery seek mental health services at higher rates after surgery than before surgery and identifies specific risk factors for increased psychiatric service use.

Exercise is a potent modulator of intestinal microbiota composition and function. In 2019, several studies uncovered biologically important links between skeletal muscle and the gut microbiota, revealing how the gut bacteria respond to an exercise challenge and have reciprocal roles in fuel availability, muscle function and endurance performance.

Although dietary protein is crucial for human health, excessively high protein intake could have negative health consequences. This Perspective serves as a word of caution against the trend of protein-enriched diets and provides an evidence-based counterpoint that underscores the potential adverse public health consequences of high protein intake.

A cross-sectional study shows that proxies of circadian misalignment, such as late chronotype and social jet lag, are associated with increased adiposity in adolescent girls but not adolescent boys, highlighting a potential sex-specific effect of circadian misalignment. Interventions targeting sleep timing should be considered in the prevention of adolescent obesity.

In this Expert Consensus Statement, the authors define 10 key characteristics (KCs) for endocrine-disrupting chemicals. They further describe the logic by which these KCs are identified and the assays that could be used to assess several of these KCs.

Early and intensive glycaemic control protects patients with type 2 diabetes mellitus (T2DM) from the development of late cardiovascular complications. The authors of the VERIFY trial now show that a more durable attainment of HbA_1c <7% is observed by adding vildagliptin to metformin as starting therapy in newly diagnosed patients with T2DM.

The relationship between type 2 diabetes mellitus (T2DM), insulin resistance and central obesity is not uniformly applicable to populations worldwide. In this Comment, we discuss the challenge of establishing waist circumference thresholds to predict T2DM in Africa.

A nationwide study conducted in the USA demonstrated that an intervention combining gamification with social incentives, conducted within the context of a behavioural economics platform, can result in a moderate yet significant increase in physical activity in adults with obesity over a period of 24 weeks with an additional 12 week follow-up.

Metformin is the mainstay therapy for type 2 diabetes mellitus. A new study shows that metformin acts directly on gut bacteria to elevate cAMP-induced agmatine production, thereby increasing lipid metabolism and lifespan in model organisms. These data identify links between metformin and gut microbiota that might be important for increasing longevity.

Sodium–glucose cotransporter 2 (SGLT2) inhibitors are a fairly new class of treatment for diabetes mellitus. Some data suggest SGLT2 inhibitors are associated with a risk of severe urinary tract infections. However, meta-analyses of trials and a large population-based cohort study show no increased risk, which provides important reassurance for patients and prescribers.

This Review outlines the mechanisms by which bile acids regulate glucose homeostasis and the settings in which endogenous bile acids are altered, and provides suggestions for future research.