Hibernating Brown Bears

Lessons Learned from the Hibernating Brown Bears

The Mind-Gut Connection“, written by Emeran Mayer, M.D., demonstrates his vast experience as a practicing gastroenterologist as he describes the connections that our brains have with our guts, especially with the microbes that make the gut their home.

Mayer is a world renowned gastroenterologist and neuroscientist with 35 years of experience in the study of clinical and neurobiological aspects of how the digestive system and the nervous system interact in health and disease. His current research focus is on the role of the gut microbiota brain interactions in emotion regulation, chronic visceral pain and in obesity.

Obesity and compromised metabolic health are often thought to be closely linked. However, a study by Fredrik Baeckhed’s group at the University of Gothenburg suggests that this is not necessarily the case – at least in brown bears!

By studying body weight and the gut microbiota in brown bears both during the summer and during the winter period – when these animals go into a 6 months hibernation period – they identified major differences in the diversity and relative abundances of certain gut microbiota. During the summer the bears overeat and dramatically gain body weight, while during the prolonged fasting period in winter they lose all the excess weight. The most fascinating aspect of this study was that despite their “summer obesity” the bears did not develop the negative metabolic changes including insulin resistance and diabetes known as metabolic syndrome, a metabolic dysregulation which has shown a dramatic increase in North America and other developed countries.

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Dr. Mayer is currently Professor in the Departments of Medicine, Physiology and Psychiatry at the David Geffen School of Medicine at UCLA, Executive Director of the G. Oppenheimer Center for Neurobiology of Stress and Resilience, and Co-director of the CURE: Digestive Diseases Research Center at UCLA.