It’s a little known fact that your gut bacteria affects your brain function. In fact it’s a 10 to 1 ratio of gut flora (bacteria) to your body’s cells.
Researchers know that the brain sends signals to the gut but now it’s discovered that the signal travels the opposite direction as well. Keep reading to find out if probiotics could help with anxiety and the gut brain connection.
Gut Brain Connection: Could Probiotics Calm Your Anxiety Down?
by: Renegade Health
That our mental state affects our digestive health is a concept most of us are familiar with. What’s new in science is that the health of our digestive system—specifically, the stomach microbes we’re carrying around with us—could have a big impact on our mental health.
In other words, if you’re feeling anxious and you’re not sure what could be causing it, it’s probably not all in your head—but more likely, all in your stomach.
Animal Study Finds Gut Microbes Affects Mental Health
It was back in 2011 that scientists from the Farncombe Family Digestive Health Research Institute at McMaster University in Ontario, Canada, published the results of an animal study indicating that gut microbes could affect mental health. They noted that previous studies had “suggested” that gut bacteria may communicate with the brain, but it was a fairly new concept, and they needed more proof.
Lead author Stephen Collins and colleagues first gave healthy mice a good dose of antibiotics to disturb their natural gut bacteria. They also gave a group of control mice water only. The results showed the following:
Behavioral changes: The mice that were given water showed no changes in behavior, but the mice given the antibiotics started acting less like mice. They were less hesitant to step off a platform and more eager to explore—more fearless overall.
Brain changes: Mice given antibiotics had an increased amount of brain protein called “derived neurotrophic factor (BDNF)” than mice given water. Such changes in levels of BDNM have been previously linked to depression and anxiety.
In the next stage of the study, the researchers started swapping the gut bacteria in the mice. Different strains of mice have different personalities—some are aggressive, and some more timid. Researchers found that changing gut bacteria made timid mice aggressive, and aggressive mice more passive.
Conclusion: bacteria in the gut produce chemicals that can access and influence the brain.
Possibilities for the future: therapies that aim to restore normal gut flora, including supplementation with probiotics, may be helpful in correcting behavior and mood changes.
An earlier study by Japanese researchers suggested the microflora in our guts are established early in life, after which it’s difficult to change them. Scientists were able to change the baseline stress characteristics of germ-free mice only until nine weeks of age. After that, no matter what bacterial additions they made to the animals’ guts, they couldn’t properly regulate stress and anxiety levels.
“There are changes that happen early in life that we can’t reverse,” said John Cryan, a neuroscientist at the University of Cork in Ireland.
Nevertheless, though we may be stuck with a basic programming between the gut and the brain that is established while we’re infants, researchers remain hopeful that tweaking those bacteria later in life can create behavioral and psychological changes.
A study led by Cryan and published in 2011 showed that anxious mice who were given the probiotic bacterium Lactobacillus rhamnosus displayed lower levels of anxiety, decreased stress hormones, and even an increase in brain receptors for a neurotransmitter vital to curbing worry, anxiety, and fear.
Veterans with Mental Health Disorders More Likely to Have Gastrointestinal Disorders
In March 2013, another study was published that again, linked mental health issues with microbes in the gastrointestinal system. Researchers examined the health records of over 600,000 Iraq and Afghanistan veterans from October 7, 2001 to December 31, 2010. They then analyzed all these records, looking for connections between gastrointestinal disorders (GIDs) and posttraumatic stress disorder (PTSD). Results showed:
- The prevalence of GID in newly returning veterans was nearly 20 percent.
- Veterans with a mental health disorder were at least twice as likely to have a GID as those without mental health disorders.
- For women, the increased risk of all GIDs was greatest among those with depression.
- Among men, the increased risk of irritable bowel syndrome (IBS) was greatest among those with PTSD.
- IBS was the GID most strongly associated with mental health conditions among both genders.
Might Probiotics Help?
As to whether probiotics might help ease anxiety, PTSD, and other mental health issues, the jury is still out. We need a number of new studies on the subject. But already we are seeing some suggested benefit. In one 2013 study by UCLA researchers, for example, healthy women who consumed a drink with four added probiotic strains twice daily for four weeks showed significantly altered brain functioning in an fMRI brain scan. The changes indicating an altering of brain regions that control the processing of emotion and sensation.
“Our findings indicate that some of the contents of yogurt may actually change the way our brain responds to the environment,” said lead author Dr. Kirsten Tillisch. “When we consider the implications of this work, the old sayings ‘you are what you eat’ and ‘gut feelings’ take on new meaning.”
Researchers are coming to the conclusion that not only does the brain send signals to the gut, but the opposite is also true—the gut sends signals to the brain.
“Time and time again,” Tillisch said, “we hear from patients that they never felt depressed or anxious until they started experiencing problems with their gut. Our study shows that the gut brain connection is a two-way street.”