“Your gut microbes are in a prime position to influence your emotions, by generating and modulating signals the gut sends back to the brain.” ―Emeran Mayer
Last week, we talked about the three primary channels of gut-brain communication. These were neural, immune, and hormonal. This week, we look at some actual psychobiotic microbes that have been clinically analyzed. The field is still young but getting stronger each day.
Where we are today
The last ten years have solidified the importance of psychobiotics to our mental health and filled in many details. Specific psychobiotic bacteria have been identified, including:
Lactobacillus rhamnosus and Lactobacillus reuteri, which both reduce anxiety by affecting GABA levels. They work via the vagus nerve.
Bifidobacterium longum 1714, which tamps down cortisol levels. Cryan and Dinan found that “consumption of B. longum 1714 is associated with reduced stress and improved memory.”
Lactobacillus plantarum 299v, which reduces inflammation and helps to soothe IBS. By lowering cortisol levels, it lowers stress-related anxiety and depression.
Lactobacillus plantarum PS128, which has been shown, in limited studies, to improve attention and communication skills in people with autism spectrum disorder.
Gut and oral microbes have been found to be associated with many conditions over the past decade, including chronic fatigue syndrome, binge drinking, long covid, dementia, Parkinson’s, ALS, sleep disturbance, and antibiotic recovery.
The definition of psychobiotic has been extended to include heat-treated non-living bacteria that seem to work by encouraging the immune system to stand down. Also added to the definition: prebiotics, which are chains of sugars (oligosaccharides) that feed beneficial microbes. In particular, fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) are considered to have psychobiotic effects.
The last decade has shown that some kinds of depression and anxiety can be ameliorated or cured with psychobiotic treatments. Dinan has introduced them to his psychiatric practice with several heart-warming successes.
It’s hard to know how many psychiatric problems are due to gut issues, but a gut workup might not be a crazy way to start to a psych evaluation. The next ten years promise even more relief from stress-related disorders, among the biggest concerns of society today. Subscribe or be left out!
References
Sudo, Nobuyuki, Yoichi Chida, Yuji Aiba, Junko Sonoda, Naomi Oyama, Xiao-Nian Yu, Chiharu Kubo, and Yasuhiro Koga. “Postnatal Microbial Colonization Programs the Hypothalamic-Pituitary-Adrenal System for Stress Response in Mice.” The Journal of Physiology 558, no. Pt 1 (July 1, 2004): 263–75.
Dinan, Timothy G., Catherine Stanton, and John F. Cryan. “Psychobiotics: A Novel Class of Psychotropic.” Biological Psychiatry 74, no. 10 (November 15, 2013): 720–26.
Ross, Kim. “Psychobiotics: Are They the Future Intervention for Managing Depression and Anxiety? A Literature Review.” Explore (New York, N.y.), February 20, 2023.
Allen, A P, W Hutch, Y E Borre, P J Kennedy, A Temko, G Boylan, E Murphy, J F Cryan, T G Dinan, and G Clarke. “Bifidobacterium Longum 1714 as a Translational Psychobiotic: Modulation of Stress, Electrophysiology and Neurocognition in Healthy Volunteers.” Translational Psychiatry 6, no. 11 (November 2016): e939.
Kaźmierczak-Siedlecka, Karolina, Agnieszka Daca, Marcin Folwarski, Jacek M. Witkowski, Ewa Bryl, and Wojciech Makarewicz. “The Role of Lactobacillus Plantarum 299v in Supporting Treatment of Selected Diseases.” Central-European Journal of Immunology 45, no. 4 (2020): 488–93.
Foster, Jane A., Linda Rinaman, and John F. Cryan. “Stress & the Gut-Brain Axis: Regulation by the Microbiome.” Neurobiology of Stress 7 (March 19, 2017): 124–36.
Mensi, Martina Maria, Chiara Rogantini, Michele Marchesi, Renato Borgatti, and Matteo Chiappedi. “Lactobacillus Plantarum PS128 and Other Probiotics in Children and Adolescents with Autism Spectrum Disorder: A Real-World Experience.” Nutrients 13, no. 6 (June 2021): 2036.
Kong, Xue-Jun, Jun Liu, Kevin Liu, Madelyn Koh, Hannah Sherman, Siyu Liu, Ruiyi Tian, et al. “Probiotic and Oxytocin Combination Therapy in Patients with Autism Spectrum Disorder: A Randomized, Double-Blinded, Placebo-Controlled Pilot Trial.” Nutrients 13, no. 5 (May 2021): 1552.
Liu, Yen-Wenn, Min Tze Liong, Yu-Chu Ella Chung, Hui-Yi Huang, Wu-Shun Peng, Yun-Fang Cheng, Yu-Siou Lin, Yu-Yu Wu, and Ying-Chieh Tsai. “Effects of Lactobacillus Plantarum PS128 on Children with Autism Spectrum Disorder in Taiwan: A Randomized, Double-Blind, Placebo-Controlled Trial.” Nutrients 11, no. 4 (April 2019): 820.