By Jennifer Copley (Last Updated 20 May 2014)
Probiotics are live bacteria that have been associated with a number of health benefits. They can be found in certain foods or taken as supplements.
The findings from a number of studies suggest that probiotics may be useful for treating and preventing anxiety and depression:
- Bravo et al. (2011) found that the L. rhamnosus (JB-1) probiotic decreased both overt expressions of anxiety and depression and underlying stress-induced corticosterone levels in mice.
- According to a recent UCLA study, women who ate probiotic-rich yogurt twice daily for a month responded better to tests of emotional reactivity, which suggests that probiotics may help with mood regulation (Champeau, 2013).
- A study of healthy volunteers who took a probiotic supplement for one month found that probiotic supplementation significantly reduced anxiety, anger and hostility, depression, and somatization (unpleasant physical symptoms caused by stress) compared to a placebo, and that the cortisol levels in the probiotic group were much lower (cortisol is a marker for stress). The same study also found a reduction in anxiety among rats that were given a probiotic supplement (Messaoudi et al., 2011).
- Rao et al. (2009) found that chronic fatigue sufferers who consumed a probiotic supplement (L casei 3) three times daily experienced significantly reduced anxiety compared to those taking a placebo (Rao et al., 2009).
- Logan and Katzman (2005) found that people who suffer from depression tend to have increased oxidative stress, high levels of pro-inflammatory cytokines, and altered gastrointestinal function, all of which may be helped by probiotics.
Why would probiotics reduce anxiety, depression, and other mood- and stress-related problems? The brain and the gut are connected via the vagus nerve (which is why many people suffer upset stomachs when under stress). A happier brain creates a happier gut and vice versa. The effect of stress on gut bacteria was demonstrated by Bailey et al. (2011), who found that exposing mice to stress reduced the bacterial populations in their intestines. Also, stress and depression are both associated with inflammation, and certain probiotic strains have been shown to reduce inflammation.
More research is required to confirm the benefits of probiotics for treating depression and anxiety, though the preliminary findings are promising and probiotics are considered safe. Unlike many of the medications used to treat anxiety and depression, side effects are extremely rare with probiotic use – the few problems that have been reported typically occurred in people who already suffered from serious illnesses. Given that they are considered harmless for most people and may provide significant benefits, probiotics are worth trying, though checking with a doctor beforehand is recommended to be on the safe side.
- Look for capsules that contain at least 1 billion colony-forming units (CFUs).
- Choose supplements that include more than one strain of bacteria.
- Eat foods that are sources of prebiotics, which help to maintain healthy populations of probiotics by acting as food for them. Prebiotic sources include whole grains, garlic, onions, leeks, bananas, Jerusalem artichokes, dandelion greens, chicory root, honey, asparagus, tomatoes, buttermilk, yogurt, and kefir.
- Store your supplements in a dark, cool, dry place
Note: I’ve provided simplified explanations for the ways in which gut bacteria may influence anxiety and depression and how probiotics may benefit those who suffer from these disorders. If you’re interested in learning more about the underlying science, see the reference list at the end of this article.
This article is provided for informational purposes only. It is not intended as a substitute for medical or psychiatric advice from a qualified doctor. Health and psychiatric concerns should be referred to an appropriate professional.
- Alexander, J. (2013, August 29). “10 Probiotic Foods to Help with Depression and Anxiety.” Toronto Sun, www.TorontoSun.com.
- Bailey, M.T.; Dowd, S.E.; Galley, J.D.; Hufnagle, A.R.; Allen, R.G.; & Lyte, M. (2011). “Exposure to a Social Stressor Alters the Structure of the Intestinal Microbiota: Implications for Stressor-Induced Immunomodulation.” Brain, Behavior, and Immunity, 25(3): 397-407.
- Bravo, J.A.; Forsythe, P.; Chew, M.V.; Escaravage, E.; Savignac, H.M.; Dinan, T.G.; Bienenstock, J.; & Cryan, J.F. (2011). “Ingestion of Lactobacillus Strain Regulates Emotional Behavior and Central GABA Receptor Expression in a Mouse via the Vagus Nerve.” Proceedings of the National Academy of Sciences, 2011.
- Bruaser, D. (2013, November 19). “Probiotics a Potential Treatment for Mental Illness.” www.Medscape.com.
- Champeau, R. (2013, May 28). “Changing Gut Bacteria Through Diet Affects Brain Function, UCLA study Shows.” UCLA, Newsroom.UCLA.edu.
- Curtin, J., MA. (2011, July 6). “Why We Crave: Understanding and Overcoming Food Addictions.” The Weston A. Price Foundation, WestonAPrice.org.
- Deans, E., MD. (2011, November 24). “Will Stress Injure Your Gut?” Evolutionary Psychiatry, Psychology Today, www.PsychologyToday.com.
- Deans, E., MD. (2012, June 17). “Do Probiotics Health with Anxiety?” Evolutionary Psychiatry, Psychology Today, www.PsychologyToday.com.
- Dieticians of Canada. (2014). “Prebiotics.” EatRight Ontario, www.EatRightOntario.ca.
- Dinan, T.G.; Stanton, C.; & Cryan, J.F. (2013). “Psychobiotics: A Novel Class of Psychotropic.” Biological Psychiatry, 74(10): 720-726.
- Elsevier. (2013, November 14). “Are Probiotics a Promising Treatment Strategy for Depression?” www.ScienceDaily.com.
- Gill, H., & Prasad, J. (2008). ” Probiotics, Immunomodulation, and Health Benefits.” Advances in Experimental Medicine and Biology, 606: 423-454.
- Jaret, P., Reviewed by L.J. Martin, MD. (2013, January 3). “What are Probiotics?” www.WebMD.com.
- Logan, A.C., & Katzman, M. (2005). “Major Depressive Disorder: Probiotics May Be an Adjuvant Therapy.” Medical Hypotheses, 64(3): 533-538.
- Martoni, C.J., & Prakash, S. (2012, November 7). “‘Bad’ and Total Cholesterol Reduced by Daily Doses Of a New Probiotic.” American Heart Association, Newsroom.Heart.org.
- Messaoudi, M.; Lalonde, R.; Violle, N.; Javelot, H.; Desor, D.; Nejdi, A.; Bisson, J.F.; Rougeot, C.; Pichelin, M.; Cazaubiel, M.; & Cazaubiel, J.M. (2011). ” Assessment of Psychotropic-Like Properties of a Probiotic Formulation (Lactobacillus Helveticus R0052 and Bifidobacterium Longum R0175) in Rats and Human Subjects.” British Journal of Nutrition, 105(5): 755-764.
- Moshfegh, A.J.; Friday, J.E.; Goldman, J.P.; Chug Ahuja, J.K. (1999). “Presence of Inulin and Oligofructose in the Diets of Americans.” Journal of Nutrition, 129(7): 1407s-1411s.
- Paddock, C., Phd. (2013, August 13). “Potential Probiotic Effects Beyond Gut: Psoriasis, CFS.” www.MedicalNewsToday.com.
- Rao, A.V.; Bested, A.C.; Beaulne, T.M.; Katzman, M.A.; Lorio, C.; Berardi, J.; & Logan, A.C. (2009, March 19). “A Randomized, Double-Blind, Placebo-Controlled Pilot Study of a Probiotic in Emotional Symptoms of Chronic Fatigue Syndrome.” Gut Pathogens, 1: 6.
- Sanchez, M.; Darimon, C.; Drapeau, V.; Emady-Azar, S.; Lepage, M.; Rezzonico, E.; Ngom-Bru, C.; Gerger, B.; Philippe, L.; Ammon-Zuffrey, C.; Leone, P.; Chevrier, G.; St.-Amand, E.; Marette, A.; Dore, J.; & Tremblay, A. (2013). “Effect of Lactobacillus Rhamnosus CGMCC1.3724 Supplementation on Weight Loss and Maintenance in Obese Men and Women.” British Journal of Nutrition, 111(8),: 1507-1519.
- Savacool, J. (2014, March 23). “Popular Probiotics Have Few Cons, Experts Say.” USA Today. USAToday.com.
- Scicurious. (2011, September 6). “Can Probiotic Yogurt Cure Your Psychiatric Ills?” Scientific American Blogs, Blogs.ScientificAmerican.com.
- The Harvard Medical School Family Health Guide. (2006). “Health Benefits of Taking Probiotics.” Health.Harvard.edu.
- Université Laval. (2014, January 28). “Certain Probiotics Could Help Women Lose Weight, Study Finds.” www.ScienceDaily.com.
- Zeratsky, K., RD, LD. (2011, September 15). “Is It Important to Include Probiotics and Prebiotics in a Healthy Diet?” The Mayo Clinic, www.MayoClinic.org.