Could our gut bacteria be ruling our minds?

Scientists have discovered that our gut microbes influence our moods and food choices, according to a new article in the journal BioEssays.

Researchers from UC San Francisco, Arizona State University, and the University of New Mexico reviewed a range of recent studies and came to the conclusion that the bacteria living in our digestive tracts doesn’t just feed on whatever we eat, but actually sends out signals for the stuff that helps it grow (which, depending on the bacteria, is often really healthy stuff like fat and sugar).

This means that our cravings aren’t down to watching too much GBBO or having zero self-control, but the fault of our gut microbes. Unfortunately, this also means that they’re hard to overcome using only willpower. Apparently this bacteria, which outnumbers the cells in our body by around 100:1, is expert at manipulating our moods, probably to make us eat what they want but possibly also just to screw with us.

The scientists think that bacteria do this by altering messages in the vagus nerve, which connects 100 million nerve cells in the body. By altering the signals they send, they can change our taste receptors, produce toxins, or flood us with happy hormones.

This explains why eating something that’s bad for our health can make us (momentarily) so happy: sneaky gut bacteria send chemicals to our brain to perk us up. But the effect is temporary, and as unhealthy food causes the bacteria to grow out of balance, it only exacerbates the problem.

Researchers have found that the effect of our microbes can be lessened through the use of probiotics, which both reduces the number of unhealthy gut bacteria and, in trials, made test subjects feel more optimistic. This could give people the boost they need to eat more healthily, as within 24 hours of changing diet, the bacteria start to behave better.

Image by MarcoTolo via WikiMedia Commons.