Home › Blog › Bacteria Found in Sewage Predicts Obesity in Cities?

There’s been a lot of attention paid recently to the gut microbiome, a collection of friendly bacteria that live in your digestive tract. Now a new study has shown that we can study this in large populations by looking at sewage…yes you read that right. In fact, the pattern of friendly bacteria in the sewage can predict with high accuracy if the population of the town it comes from is fat or thin.

So what would gut bacteria have to do with weight and how can it be that sewage predicts obesity? Recent research has been emerging that your gut has many different types of bacteria and when the delicate balance between them is upset, we begin to see problems. For example, this is why antibiotics that can kill off these friendly bacteria can lead to diarrhea or worse – like a nasty cDifficile infection. More recently, research has shown that the pattern of bacteria in your gut also determines or effects your weight. So heavy people have different gut microbiomes than skinny people. Why? It’s thought that since the gut bacteria eat up some of your food to survive, that people with more friendly bacteria have some calories consumed by these bugs. In addition, when the bad bacteria take over the usual delicate balance with the good bacteria, toxic chemicals produced by the bad guys can lead to a leaky gut syndrome and chronic inflammation, which can lead to abnormalities in blood sugar control and weight gain.

The new study looked at samples of sewage from 71 U.S. cities and used genetic testing to determine the bacterial fingerprint of each – i.e. the pattern of the types of bacteria in the waste. The researchers found distinct patterns of bacteria in the sewage that matched the common patterns seen in individuals. In fact, they found 27 distinct patterns of bacteria in the sewage and amazingly, they could predict the average weight of the town based on those patterns with more than 80% accuracy!

The upshot? The research on weight and gut bacteria is getting mature enough that if you’re carrying extra pounds, you should be looking at probiotic supplements for yourself. In particular this sewage study found that obese cities had more of a bacteria called Bacteroides spp. which can lead to the leaky gut syndrome I described above and had fewer Faecalibacterium spp. bacteria. While I can’t find any probiotic supplements with that specific good bacterial strain, there have been animal studies showing that taking the more common strains (Lactobacillus paracasei, L. rhamnosus, and Bifidobacterium animalis) can help to control weight and control blood sugar while down regulating gut inflammation. Human studies with Lactobacillus casei Shirota (LcS) have begun to show the same thing. So you may want to find a good probiotic supplement with these strains!

Chris Centeno, MD is a specialist in regenerative medicine and the new field of Interventional Orthopedics. Centeno pioneered orthopedic stem cell procedures in 2005 and is responsible for a large amount of the published research on stem cell use for orthopedic applications. View Profile