Your guts play host to bacterial hunger games

Trillions of bacteria are fighting it out for survival, and the scene of the battle is your gut. But fortunately, say researchers at Oxford University, it’s good for you.


Scientists have known for some time that the human gut contains large communities of microorganisms, many of which contribute to healthy digestion and immune system function. But a study published recently in Science found that, far from cooperating with each other as previously thought, the bacteria in these communities are perpetually at war. The results may help to explain how the communities maintain relatively constant sizes and compositions over time, and in doing so, contribute to human health.

“The assumption has always been that because these bacteria are doing us good, the communities must be cooperating with one another,” said Kevin Foster, Professor of Evolutionary Biology at Oxford University. “What our work suggests, based on a wide-ranging mathematical analysis, is that competition may be key to a healthy gut.”

Using computer models, the team tested the stability of communities made up of cooperative and non-cooperative bacteria. They found that when most of the bacteria were willing to live and let live, the community’s composition became irregular, with some types of bacteria disappearing altogether. Predominantly competitive communities, however, where bacteria fought for food or space, kept much more stable compositions over time.

The researchers also speculated that even the “host” (i.e. your body) enters the fray every now and then.

“The hypothesis we put forward is that hosts actively intervene to help maintain the stability created by the competitive environment,” said Foster. “One obvious way to do this is through the immune system suppressing overabundant bacteria.”

Alternatively, said Foster, the body could actively separate bacteria or even feed certain members of the community instead of others, all in the interest of maintaining a balanced, healthy gut.

Let the Bacterial Hunger Games begin.

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