Key Message: The absence of certain gut bacteria has been shown to burn more calories
Action Point: Further research will hopefully identify new ways to suppress or modify the gut bacteria in an effort to reduce obesity
In the past few years, research has started to show how microbiota (AKA gut bacteria) has an impact on the way calories are absorbed and how fat cells develop. Now, scientists from the University of Geneva (UNIGE), Faculty of Medicine, Switzerland have recently been able to demonstrate on mice how the absence of microbiota has a remarkable effect against obesity which could revolutionise new anti-obesity treatments.
They have discovered that the absence of gut bacteria in mice triggers a surprising metabolic mechanism: an increase in white fat cells, which in fact cause obesity and insulin resistance. These white fat cells are transformed by gut bacteria into cells known as “beige fat” which are similar to brown fat in that they protect the body against excess weight and its consequences.
White fat, which is used as energy storage, makes up around 25% of the body mass of a healthy person. However an excess of white fat contributes to insulin resistance and diabetes while brown fat does the opposite. Cells, similar to brown fat, called beige fat, can develop within white fat, a process known as “browning” as a response to cold or exercise.
The increased production of beige fat within white fat means the more calories burned and this then suggests that a way to reduce obesity and limit insulin resistance could be to stimulate beige fat growth.
It has only been recently that scientists have started to understand the unexpected role of gut microbiota. Researchers from UNIGE Faculty of Medicine have shown that it has a direct impact on obesity and that the microbiota composition of obese people is different to that of lean people.
The scientists observed the depletion of microbiota, predominately through antibiotics, stimulated the development of beige fat in the same way as when exposed to cold or exercise. The reason for this is due to a specific cell type called macrophages, which are an essential part of the immune system and manage various metabolic functions.
During the study, the effect of the antibiotics lasted a couple of weeks after treatment
It is unrealistic to treat obesity with high doses of antibiotics given the risk of antibiotic resistance so the co-authors of the study said further studies are needed and they are keen to “explore alternative ways of suppressing or modifying the microbiota and try to identify the exact bacterial genes responsible for the phenomenon”. In doing that, they could then only target those genes without having to deplete the whole microbiota.
References
- Université de Genè “How depleting the gut microbiota protects from obesity.” ScienceDaily. ScienceDaily, 16 November 2015. Accessed online on 27 November at http://www.sciencedaily.com/releases/2015/11/151116120605.htm
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Written by: Sandra Di Giacomo |
