January 18, 2016
You’ve heard us say that we’re made up of more bacterial cells than human cells. In fact, our gut is host to tens of trillion bacteria, and scientists are discovering more and more every day about the link between our brain chemistry and the bacteria in our gut.
What you might not know is that our gut actually has a brain of its own – the enteric nervous system (ENS), and it’s often referred to as our second brain. No – it doesn’t actually work like the one in our head, but our brain and our gut are interconnected by hundreds of millions neurons and a highway of chemicals and hormones that are constantly providing feedback about how hungry we are, whether or not we’re experiencing stress, even if we’ve ingested something undesirable.
There’s actually a cross-talk happening between our brain and our gut that actually takes place through the Vagus Nerve. This nerve starts in our brain stem and runs all the way through our body ending in our abdomen. It’s a highway of information that connects our second brain to the one in our head, making sure they’re both in constant communication. It’s not just metaphorical when you get those feelings of “butterflies” in the pit of your stomach or when you hear someone tell you to “trust your gut instinct” or that they have a “gut feeling”. When things don’t go well, our brain is really telling our gut about it and usually our gut doesn’t react so well.
Up until fairly recently, little was known how our gut affected our mood, but now there’s mounting scientific evidence to support that there is a connection between our gut and how we feel. As we wrote in our blog “How your Gut Influences your Mood”, women who ate yogurt containing a mixture of probiotic bacteria twice a day for four weeks reacted less to angry and frightening visual stimuli than women who didn’t get probiotic bacteria.
To further understand how gut bacteria impacts brain chemistry, Dr. John Cryan along with his colleague Dr. Tim Dinan, neuroscientists from the University of College Cork in Ireland, experimented with lab mice by feeding a small group a broth laden with Lactobacillus rhamnosus, a strain of bacteria that lives naturally in our digestive tract, and compared them to mice who weren’t given the broth. The mice that were given the broth with probiotics performed better under duress. According to Dr. Cryzan, The mice behaved as if they were on Prozac,’’ Cryan told The New York Times. ‘‘They were more chilled out and more relaxed.
Other similar mood-related studies have been performed in France and the Netherlands using human participants. French researchers used doses of Lactobacillus and Bifidobacterium probiotics which yielded beneficial psychological effects including lowered depression, less anger and hostility, anxiety, and better problem solving, compared with the placebo group.
The study in the Netherlands, gave human participants a course of multiple species of Bifidobacterium and Lactococcus (not to be confused with Lactobacillus) probiotics over a four-week period in which the test group showed a significantly reduced overall cognitive reactivity to sad mood, which was largely accounted for by reduced rumination and aggressive thoughts compared with the placebo-fed control group.
Up to now, we’re learning that the two main strains of probiotic bacteria, Bifidobacterium and Lactobacillus, show beneficial effects on mood. However, much more research is needed to discover why some bacteria have a positive effect and while other strains don’t. What we do know, as a society, many of us are not in touch with maintaining good “gut” health. We need to trust our gut instinct. So the next time your gut tells you something isn’t right, listen. It’s knows a lot more than you think.
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