An Opportunistic Pathogen Isolated from the Gut of an Obese Human Causes Obesity in Germfree Mice

December 30th, 2012

If you’re like me, you’ll go looking for what the WTP diet is, maybe even read the supplementary information to this study.

The specifics about what was given to the test subject aren’t included anywhere, I was guessing because it was a sample size of one. I still wanted to know.

I emailed Dr. Liping Zhao, one of the authors of the study. They had been inundated with emails about this. The response is below:


I was reading the Supplementary Information to, “An opportunistic pathogen isolated from the gut of an obese human causes obesity in germfree mice” and I was trying to determine what this statement actually means:

“This volunteer was given a diet composed of whole grains, traditional Chinese medicine and prebiotics (WTP diet) for intervention.”

Which Chinese medicine and which prebiotics?

Thank you for your time,
Kevin Flaherty

Dear Kevin,

Thank you for your interest in our recent research discoveries. Since the publication of our paper, I have received hundreds of emails from across the globe, hence my apologies for not able to reply to your email earlier.

Through personal experience, I have come to understand the immense physical and mental burden associated with obesity and ill health. Thus I completely understand your earnest interest in the WTP diet described in our papers. However, the idea that one food item or one combination of food items could solve anyone’s health problem is simply not in line with the scientific spirit. We do not believe in a “one-size fits all” solution for the universal obesity challenge. When volunteers participate in our gut microbiota-targeted dietary intervention, each of their diet is tailored according to the DNA-based analysis of their gut bacteria population, and is administered with great care and regular health check-ups under the supervision of a team of trained doctors, dietitians and researchers. Thus it would be very irresponsible of me to attempt to give you any blanket statement advice without knowing your specific health condition and your gut bacteria composition and activity.

As a scientist, I am first and foremost interested in the welfare of the general public. Thus, I never hesitate to share any findings that could be beneficial to the public. In my interview with Science early this year, I have already shared the food items that have proven to be helpful in promoting the growth of beneficial gut bacteria and reducing the detrimental ones (June 7th 2012 issue of Science). While inclusion of a certain dose of prebiotic foods such as Chinese yam and Chinese bitter melon in the diet has worked for most of our study volunteers, the specific dose used is decided on an individual basis. I would recommend you to try these food items with care and caution, and also try to increase the amount of fiber intake in your everyday diet by taking more natural whole grains.

If possible, I would also recommend a closer read of our recent paper published in the ISME journal. It is an open assess article, free to download at the following link:

While the many news articles provide an interesting highlight of our research, the paper itself provides a more scientific account of our findings. Our study followed the Koch’s postulate in demonstrating the causative role a gut bacterium plays in human obesity. Our work is the first for demonstrating the obesity-causing capacity of a human gut bacterium, thus, proving that its overgrowth in the gut of its severely obese human host should be the reason not result of obesity. Our work in germfree mice also showed that both bad diet and bad bacteria are required for the animals to become obese and insulin resistant.

Our research doesn’t stop here. B29 is not the only bacterium that has such causative effect on human obesity. Rather our paper established a protocol to discover more of such bacteria. We foresee that many such bacteria would be identified in the near future. With a deeper understanding of all the relevant gut bacteria populations and their relationship to human health, we would be able to offer better advise of how certain diet patterns could promote helpful bacteria growth and in turn benefit human health.

From my own experience of working with many severely obese and diabetic children and adults, I know that the battle against this metabolic disease requires tremendous willpower, dedicated effort and scientifically validated technology. The good news is that it can now be done with the introduction of gut microbiota technology as demonstrated by the human case in our ISMEJ paper.

We look forward to sharing subsequent findings with all who are interested. Again, thank you very much for your inquiry.

Happy New Year,
Dr. Liping Zhao
PhD, Professor in Microbiology,
Director of Laboratory of Molecular Microbial Ecology and Ecogenomics
Associate Dean of School of Life Sciences and Biotechnology
Director of Laboratory of Nutritional Systems Biology
Shanghai Center for Systems Biomedicine
Shanghai Jiao Tong University

Via: Nature:

Lipopolysaccharide endotoxin is the only known bacterial product which, when subcutaneously infused into mice in its purified form, can induce obesity and insulin resistance via an inflammation-mediated pathway. Here we show that one endotoxin-producing bacterium isolated from a morbidly obese human’s gut induced obesity and insulin resistance in germfree mice. The endotoxin-producing Enterobacter decreased in relative abundance from 35% of the volunteer’s gut bacteria to non-detectable, during which time the volunteer lost 51.4kg of 174.8kg initial weight and recovered from hyperglycemia and hypertension after 23 weeks on a diet of whole grains, traditional Chinese medicinal foods and prebiotics. A decreased abundance of endotoxin biosynthetic genes in the gut of the volunteer was correlated with a decreased circulating endotoxin load and alleviated inflammation.

Related: Gut and Psychology Syndrome by Natasha Campbell-McBride

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