Scientists now know that gut microbes almost certainly play a role in us getting fat, and poop transplants are sometimes touted as a potential route to weight loss. But if that’s a little too icky for you, Vanderbilt scientists have been experimenting with more refined microbiome tinkering in mice using genetically modified E. coli.


Previous experiments have taken gut bacteria from obese humans and put them in mice. The mice later grew fat even though their diet stayed the same. But these experiments involve transplanting thousands of different bacteria at once, and no one is really sure how they work together to make a mouse fat or not.

A recent obesity study presented at American Chemical Society meeting and reported on by MIT Technology Review also involves gut microbes, but its guiding principle is quite different. Instead of altering the overall microbial makeup of the gut, the Vanderbilt team added just one type of bacteria genetically modified to be, essentially, a little drug factory right in the gut.




The bacteria was your common E. coli, but it carried a gene for N-acyl-phosphatidylethanolamines, molecules which become converted to appetite-suppressing molecules. Over 8 weeks, the mice given this bacteria gained 15 percent less weight than those that did not.

This technology is definitely not ready for primetime after just one mouse study. One complication, for example, is getting bacteria to survive in a gut naturally teeming with microbial competitors. But it does bring up the intriguing and far-off possibility of hacking our microbiome to create a perpetual drug factory within. It’s not that crazy if you consider that bacteria in our gut actually make most of our vitamin K. Why not appetite suppressors or even other vitamins? Instead taking a pill everyday, one pill of bacteria could last you a lifetime. [Tech Review]

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