We know from previous research that the bacteria in our guts can influence our mood. Jerry Kennard, Ph.D., explains that harmful bacteria in our gut can make us more anxious and probiotics can have the opposite effect. In another post, Dr. Kennard explains that anxiety might be relieved by taking certain types of prebiotics — plant-based nutrients that enhance good bacteria already existing in the gut.
But we still don’t know exactly how this happens. How does bacteria living in your intestines communicate with your brain about moods and levels of anxiety?
Scientists set out to learn why and the results of their study were published online at Microbiome. The researchers looked at the behavior of mice — some that had gut bacteria and some that were raised in a sterile environment and did not. The researchers discovered that the presence or absence of gut microbiota influences microRNAs, which are molecules that keep cells working properly in brain regions that control anxiety levels, the amygdala, and prefrontal cortex.
When the researchers looked at the brain regions of the mice that did not have gut bacteria, they found an overabundance of some microRNA and a shortage of others compared to the other mice. Next, the scientists exposed the sterile mice to gut bacteria and again looked at brain activity. The microRNAs had changed and were now closer to mice that already had the gut microbes.
The researchers also examined rats that had been given antibiotics that killed the bacteria in their gut. The rats had similar microRNA changes that they had seen in the mice that were raised in the sterile environment.
While the scientists still aren’t sure how these changes happen, the results shed light on the process. The researchers now know that:
- The presence or absence of gut bacteria affects the microRNA in the brain.
- Adding gut microbes can alter the microRNA.
This gives them a place to focus further research. The researchers are looking at whether they can use probiotics to manipulate the types and amounts of gut bacteria and therefore adjust the microRNA. This information could lead to new medications that would target the molecules in the brain that influence anxiety and other psychiatric and neurological disorders.
Should you take probiotic supplements?
Research hasn’t provided any solutions yet. Some people might tell you that eating more yogurt or taking probiotic supplements will help your anxiety. Probiotics are live bacteria and microorganisms that promote proper bodily function. They have been shown to relieve diarrhea, according to Berkeley Health; however scientific evidence for other health benefits, such as enhanced immune responses, weight loss, or anxiety is limited.
The good news is that probiotics are generally considered safe. Side effects can include mild gas and bloating. Berkeley Health recommends that people with compromised immune systems and pregnant women should discuss the use of probiotics with their doctors and that you should never give infants and young children probiotics.
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Eileen Bailey is a freelance health writer. She is the author of What Went Right: Reframe Your Thinking for a Happier Now, Idiot’s Guide to Adult ADHD, Idiot’s Guide to Cognitive Behavioral Therapy, Essential Guide to Overcoming Obsessive Love, and Essential Guide to Asperger’s Syndrome. She can be found on Twitter @eileenmbailey and on Facebook at eileenmbailey.