Scientists seek explanations for the obesity epidemic that is hitting the affluent world: increasingly sedentary lifestyles, junk food, excessive consumption of fast releasing sugars and fructose… or overuse of antibiotics?
I was struck by a sequence of three articles published respectively in 2009, 2011 and 2013, all discussing intestinal microorganisms called methanogens, which produce methane gas. These are very specific microorganisms, which differ from all conventional bacteria, even if all of them share fundamental proprieties that are they are all single-celled organisms without a nucleus.
These intestinal methanogens belong to what is called the kingdom of archaea as opposed to bacteria (in the true sense of the term). Together, archaea and bacteria are what we call prokaryotes. These are fundamentally different to eukaryotes or all unicellular or multicellular organisms characterized by the presence of a nucleus in each cell. Eukaryotes therefore include humans, animals, plants and fungi (multicellular organisms), plus the protists (single cellular organisms with a nucleus, unlike archaea and bacteria).
Methanogenic archaea have recently caught the attention of scientists, especially the Methanobrevibacter smithii species. Its high prevalence in the human intestine was fully recognized in 2009. You can find the relevant scientific reference with slide #47 of the “GI Ecology 1 – Microflora (part 2)” conference on my website www.gmouton.com (see tabs “Conferences” then “Intestinal Ecosystem”).
Two years later, it was the Research Unit on Emerging Infectious and Tropical Diseases at the University of the Mediterranean in Marseille, which informed the medical world that methanogenic archaea are highly resistant to antibiotics. Details of this little known publication (dated 2011) appear on slide #48 of the same conference noted in above. The end result is the progressive selection of methanogenic microorganisms, abundant in the human intestine and resistant to common antibiotics, which leads to their increasing proliferation….
The third article was published on 26 March 2013 in the leading medical journal Endocrinology by the prestigious Cedars-Sinai Medical Center in Los Angeles. You can read the conclusions in slide #49 following the two slides already mentioned. In summary, the authors highlighted a strong link between the presence of the Methanobrevibacter smithii archaea in the human intestine and an increased body mass index (BMI) along with a higher body fat percentage, as this methanogen increases the extraction of nutrients from our food and therefore contributes to weight gain.
Finally, the successive discoveries concerning the Methanobrevibacter smithii, this “bacteria” that is not really a bacteria, merely highlights in humans what we have long understood to be true in farmed animals: antibiotics promote weight gain! This property has been widely exploited to amplify the profits from cattle, to the extent that these practices are now banned in many countries. The use of antibiotics for preventive purposes, really meaning for fattening animals, is finally explicitly prohibited!
However, nobody until now has really wondered about the fate of humans in this regard. Antibiotics use for humans is still being prescribed relentlessly for anything and everything, instead of saving them for serious infections where they play a crucial role. With the overuse of antibiotics we play sorcerer's apprentice in selecting an aberrant intestinal microflora that dramatically increases our capacity to extract calories from our diet. We are indeed changing the course of the evolution of the human species…