Why researchers think the gut holds the key to depression

Forget the brain. The latest advancements in the treatment of depression and anxiety are coming from a more unlikely source – the gut.

Hamilton researchers have found a connection between the gut and fighting depression

Dr. Wolfgang Kunze, right, and Dr. Azucena Perez-Burgos are studying the impact the gut has on depression and anxiety. (Samantha Craggs/CBC)

Forget the brain. The latest advancements in the treatment of depression and anxiety are coming from a more unlikely source – the gut.

Hamilton researcher Wolfgang Kunze has found that future treatments for some mental health disorders may not lie with drugs at all, but in understanding the role the gastrointestinal tract plays in sending signals to the brain.

Kunze, a researcher with the Brain-Body Institute at St. Joseph’s Healthcare, has discovered a new nerve pathway in the gut that is key to sending signals from an anti-depressant and anti-anxiety microbe to the brain.

The more we understand those microbes, he said, the more we can find natural treatments – such as eating the right foods, or low-grade electrical stimulation – to treat depression.

The gut is so powerful that it has its own nervous system, and it possesses a gatekeeper, or “little brain” that controls the signals it sends to the brain, particularly as it pertains to mood.

Gut may determine speed of "death clock," researcher says

“The little brain has a million nerve cells,” Kunze said. “It’s an ancient nervous system. I call it the gatekeeper.”

Kunze’s findings were recently published in the journal FASEB, or Federation of the American Societies for Experimental Biology. His team of international researchers have been studying signals in mice, and plan for human trials over the next year.

Kunze’s mouse trials showed that the gut could send signals from specific probiotic bacteria, which have anti-depressant and anti-anxiety properties, to the brain.

“If the system acts in the same way in humans, it could allow us to use existing treatments for anxiety and depression differently,” said John Bienenstock, director of the McMaster Brain-Body Institute at St. Joseph’s Healthcare.

Kunze’s work on the “little brain” started in 1995. He’s since come across an even more tantalizing glimpse of what the gut holds – it seems to determine the speed of the “death clock” that winds down with our bodies.

“It may well be the gut that primes the body and tells the clock to count down,” he said. “If its speed is government by a signal from the intestines, there are very real indications.”

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