Our bodies are teeming with trillions of bacteria, in particular in our guts. We know that they are crucial for our health. But science is still a long way from being able to explain the precise interactions between the bacteria and what their individual properties are. SPIEGEL ONLINE has published an interesting interview on this issue with Emeran Mayer, a doctor and neuroscientist. A German native, Mayer is a professor at the University of California in Los Angeles and researches gut-brain interactions.
One issue of current debate is whether the influence of our gut flora extends beyond merely making us gain weight rapidly or letting us stay slim, i.e. if the bacteria in our gut also manipulate our psyche. One experiment saw the transfer of gut flora from bold mice to timid mice. As a result, the latter became bolder, SPIEGEL ONLINE reports. Emeran Mayer advocates caution when making generalisations based on these experiments: “These were sterile mice, i.e. animals lacking a gut flora. Applying this to human beings is difficult.”
In one of his own studies, test subjects were given yogurt with specific bacterial strains. Did their courage also increase? “No”, Mayer says. “Possibly because they were completely healthy.” He intends to repeat the study with anxiety patients. After all, the yogurt-eaters’ brain regions of the limbic system, which process negative emotions, were less active. “However, this wasn’t evident in their behaviour”, the neuroscientist offers by way of perspective.
Healthy bacteria to combat anxiety and depression – we haven’t come this far. But some scientists are convinced that there are connections. Several “think that powerful hunger sensations are caused by gut bacteria”, Mayer explains.