Probiotics Found to Reduce Stress

Probiotics and stress

Photo by Adam Borkowski

Researchers from Ireland’s University of College Cork has found that intestinal probiotics reduce stress by reducing corticosterone and altering GABA in the brain.

The study, led by Dr. John Cryan, a professor of anatomy at UCC, studied the probiotic Bifidobacterium breve 6330, and its effects upon brain chemistry. Dr. Cryan and co-researchers found that Bifidobacterium breve 6330 reduced a component called the brain-derived neurotrophic factor, or BDNF.

The brain-derived neurotrophic factor, or BDNF, is heightened during periods of stress, family separation, and psychological problems. It has been seen among higher levels of corticosterone and digestive difficulties such as irritable gut syndrome (IBS), Crohn’s disease and other digestive disorders.

After feeding the probiotic mix to mice, the researchers saw significant reductions in anxiety and stress responses. The research also found that the effect was most notable among the hippocampus – a area of the brain that monitors and regulates stress response in the body.

Probiotics and the gut-brain axis

The implication is that probiotics like Bifidobacterium breve are a key link between what has been termed the gut-brain axis. This has prompted many researchers to label the axis the “microbiome-gut-brain axis.”

The study was published in this month’s Food Nutrition & Science.

“There is increasing evidence revolving around what is now being called the ‘microbiome-gut-brain axis,’ that suggests there’s an interaction between the bacteria in the stomach and intestines, the gut, and the central nervous system,” commented Phil Lempert founder of Food Nutrition & Science and CEO of The Lempert Report.

Dr. Cryan also led another study this year, published in the Proceedings of the National Academy of Sciences. In this study, Lactobacillus rhamnosus was found to alter GABA expression in the brain in a way that reduced anxiety and depression. The research found that the feeding L. rhamnosus to mice increased their levels of GABA among the cortical regions of the brain, while reducing GABA expression in the stress-related hippocampus, amygdala, and prefrontal cortex regions – regions known to be involved in stress response.

GABA, or gamma-aminobutyric acid, has been the subject of considerable research showing that it can regulate nervous responses. While most assume that GABA always inhibits the flow of electrical activity between nerves, it also can increase nerve activity – depending upon when and where it is expressed.

The ability of probiotics to reduce stress-related digestive issues has been confirmed in clinical human research as well. In 2008, French scientists  gave 64 human volunteers with high levels of stress and incidental gastrointestinal symptoms either a placebo or Lactobacillus acidophilus Rosell-52 and Bifidobacterium longum for three weeks. At the end of the three weeks, the stress-related gastrointestinal symptoms of abdominal pain, nausea and vomiting decreased by 49% among the probiotic group.

Learn more about and how to use probiotics to improve health and reduce stress:

ProbioticsBook by Case Adams Naturopath


Diop L, Guillou S, Durand H. Probiotic food supplement reduces stress-induced gastrointestinal symptoms in volunteers: a double-blind, placebo-controlled, randomized trial. Nutr Res. 2008 Jan;28(1):1-5.

O’Sullivan E, Barrett E, Grenham S, Fitzgerald P, Stanton C, Ross RP, Quigley EM, Cryan JF, Dinan TG. BDNF expression in the hippocampus of maternally separated rats: does Bifidobacterium breve 6330 alter BDNF levels? Benef Microbes. 2011 Sep 1;2(3):199-207.

Bravo JA, Forsythe P, Chew MV, Escaravage E, Savignac HM, Dinan TG, Bienenstock J, Cryan JF. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U S A. 2011 Sep 20;108(38):16050-5.

Adams C. Probiotics – Protection Against Infection: Using Nature’s Tiny Warriors To Stem Infection and Fight Disease. Logical Books, 2014.

Case Adams is a California Naturopath with a PhD in Natural Health Sciences, and Board Certified Alternative Medicine Practitioner. He has authored 26 books on natural healing strategies. “My journey into writing about alternative medicine began about 9:30 one evening after I finished with a patient at the clinic I practiced at over a decade ago. I had just spent the last two hours explaining how diet, sleep and other lifestyle choices create health problems and how changes in these, along with certain herbal medicines and other natural strategies can radically yet safely turn ones health around. As I drove home that night, I realized I needed to get this knowledge out to more people. So I began writing about health with a mission to reach those who desperately need this information. The strategies in my books and articles are backed by scientific evidence along with wisdom handed down through traditional medicines for thousands of years.” Case connects with the elements by surfing, hiking and being a beach bum.

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