John Donne wrote, “No man is an island.” Scientists would agree — man is more like a forest.
And just like the flora and fauna that call the forest home, each human body houses tons of other species in the form of microbes. In fact, most people have 10 times more microbes in and on them than their own cells!
These microscopic organisms live on skin, within the gastrointestinal tract, and inside mouths, helping the human body function and keeping it healthy. Now, new research shows that a certain microbe has huge influence on a person’s weight.
Science is just beginning to understand how the relationship between microbes and human cells, tissues, and organs contributes to good health. The key here is mutualism — the cooperation that benefits both the microbes and the human.
Disruption of the relationships of a person’s microbiome can lead to problems. For example, oral antibiotics can upset the microbiome in the gut, resulting in the discomfort some people experience while taking them. While antibiotics are made to be effective against specific types of bacteria, they also disrupt the normal population of bacteria in the intestinal tract. The types and amount of necessary bacteria here are altered. This results in major changes in the interaction between bacteria and cells lining the gut, much to a person’s dismay and inconvenience.
A recent study shows that a bacterium in the intestines appears to control diet-mediated obesity. Akkermansia muciniphila is a common resident of the human gut, living in the layer of mucus that coats the surface of the intestinal tract. In a healthy person, this bacterium can be 3 to 5 percent of all the bacteria present — that’s a lot. The amount of Akkermansia muciniphila in a person’s intestinal tract is highly correlated with their weight. That is, people with low numbers of Akkermansia muciniphila are more likely to be obese and have type II diabetes, and those with high numbers are more likely to have a healthy weight.
To figure out this connection, researchers used mice that were fed either a normal diet or a high-fat diet and monitored the number of different bacteria in their guts. As expected, mice fed the high-fat diet became obese, but their levels of Akkermansia muciniphila were 100 times lower than mice fed the normal diet. Furthermore, when the obese mice on the high-fat diet were also given this bacterium, they lost weight and lowered the incidence of diabetes.
This has some remarkable implications and possibilities for future therapies. The interplay between bacterial populations and the host can prevent some major human health issues, like obesity or diabetes. Perhaps Akkermansia muciniphila will soon be an ingredient in probiotics and yogurts and start a new weight-loss trend.