Taking a probiotic could reduce anxiety if it contains a specific type of bacteria. A new study published in PLoS One has found that, among the many strains of probiotics, Lactobacillus (L.) rhamnosus has the most evidence showing that it could significantly reduce anxiety.
Researchers analyzed 22 animal studies and 14 human clinical studies looking at the impact of probiotics on anxiety. While researchers could not find conclusive evidence in human studies, they did find that probiotics, specifically those containing Lactobacillus (L.) rhamnosus, significantly reduced anxiety-like behavior in rodent studies. Probiotics particularly helped rodents exposed to stressful conditions or ones that had intestinal inflammation.
Probiotic supplements have been a promising area of research that focuses on the microbiota-gut-brain axis, the connection between beneficial gut microbes living in the gut and physical and mental health. There is emerging evidence that probiotics can help boost mood and protect the body against the harmful physical and mental effects of stress.
A lack of beneficial microorganisms in the gut has been associated with issues such as irritable bowel syndrome, Alzheimer’s disease, and depression. Gut bacteria can be altered by intestinal infections or by taking antibiotics, both of which can kill off beneficial or “good” bacteria. One study found that having an intestinal infection is associated with an increased risk of developing an anxiety disorder over the next two years. Some studies have linked antibiotic use with developing anxiety disorders later in life.
Probiotics can therefore be helpful to establish, or reestablish, beneficial microorganisms in the gut, especially when there is a deficiency of good bacteria. This is why doctors are increasingly suggesting taking probiotics along with antibiotics.
While Lactobacillus (L.) rhamnosus is the probiotic strain with the most current data to reduce anxiety, there may be several other strains that could help, but more research is needed to identify these strains. Ongoing research will help unlock the promising potential of probiotics in the treatment of anxiety.
Reis DJ, Ilardi SS, & Punt SEW. The anxiolytic effect of probiotics: A systematic review and meta-analysis of the clinical and preclinical literature. PLoS One. 2018; 13(6): e0199041. Published online 2018 Jun 20. doi: 10.1371/journal.pone.0199041