Fat and fit

March 10, 2016 - 11:45
photo: Ole Fröbert

 

In humans, obesity is linked to the development of diabetes and the gut microbiota has a vital role in providing calories from the diet to the host. Brown bears, however, overeat during summer and build up significant fat depots, but remain metabolically healthy. During hibernation in winter bears mobilize the stored lipids.

A cooperation of Gothenburg University, the Scandinavian Brown Bear Research Project, Örebro University and Duke University lead by Felix Sommer , now at the Institute of Clinical Molecular Biology, IKMB, Kiel University, and Fredrik Bäckhed , studied free-ranging brown bears and found seasonal changes both in the gut microbiota and metabolism of the brown bear.

The researchers transplanted the seasonal bear gut microbiota onto germ-free mice that were born and raised sterile without any bacteria. In these experiments, the mice colonized with the bear summer microbiota gained more adiposity, but, just like the brown bears, remained metabolically healthy. Despite gaining more fat, the mice did not show an impaired glucose tolerance.

The finding that the bear summer microbiota promotes extraction of energy from the diet without the adverse effects of insulin resistance might not help to treat obesity but give clues for novel therapies to treat states of undernutrition, for example malnutrition, anorexia or cancer.

The article The gut microbiota modulates energy metabolism in the hibernating brown bear Ursus arctos has been published online in Cell Reports on February 4th.

Comment by Dill-McFarland et al. in Trends in Microbiology: Bears Arouse Interest in Microbiota's Role in Health

For more information on the Scandinavian Brown Bear Research

Media coverage:

BBC: “Bears hibernate 'with bacterial help'

Der Spiegel 6/2016: Fett, aber fit

Süddeutsche Zeitung: Gesund mit Winterspeck

Deutschlandfunk: Fett ohne Diabetes - Die Tricks der Braunbären