A protein that breaks down iron compounds in the blood could be the key to why some people who are obese can maintain healthy metabolisms and do not develop diabetes.

Andrew Pospisilik of the Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany, Harald Esterbauer at the Medical University of Vienna and their colleagues examined liver and fat tissue from both 'healthy' obese people and obese people who were resistant to insulin. The authors found lower levels of a molecule called haem oxygenase-1 (HO-1) in the healthy individuals. Obese mice engineered to lack the gene responsible for HO-1 production remained sensitive to insulin and had fewer metabolic problems than normal obese mice. HO-1 may be involved in inflammation that leads to metabolic disease, and finding ways to inhibit it could lead to new therapies, the authors suggest.

Cell 158, 25–40 (2014)