Prebiotics and probiotics are two related components of food and nutrition with major benefits for health. Probiotics are living microorganisms that can live in your gut and have a positive impact on digestion and other physiological processes. A normal, healthy gut contains an incredibly large number of microbes, most of which are beneficial – together, this is referred to as the gut microbiome. Prebiotics, in contrast, are a relatively newer concept and are defined as substances that provide food for probiotics (1,2).
The purported benefits of prebiotics and probiotics are wide-ranging, from digestive health to mental health. Some of the benefits are well-supported by rigorous research, whereas others are so far only supported by small observational studies or anecdotal accounts. This article will focus on probiotics, with a companion article discussing prebiotics.
Probiotics can be found in many fermented foods, such as yogurt, kimchi, kombucha, and fermented cheeses. Probiotic supplements are also widely available. In terms of digestive health, researchers have found some evidence that probiotics can help patients with irritable bowel syndrome (IBS) and infectious or antibiotic-associated diarrhea (3-7).
IBS is difficult to treat, as the underlying cause is not well understood. Patients with IBS have been found to have a different gut microbiome profile, but it is not clear whether that is a cause or an effect (3,5). Trials of probiotics have reported conflicting results, but a review by Moayyedi et al. concluded that the overall evidence suggests probiotics have a benefit for IBS patients, though further research is needed to determine what the best treatment protocol is, given that there are many different types of probiotics and given the heterogeneity of IBS itself (3-5).
The link between probiotics and diarrhea caused by a disruption to the normal gut microbiome is more intuitively clear. Dysbiosis, caused by either being infected by a harmful gut microorganism or by antibiotics that broadly kill gut microorganisms and leave space for harmful ones to proliferate, can be improved by adding beneficial microbes back into your system. Probiotics can improve recovery in infectious diarrhea and can also help prevent diarrhea in patients taking antibiotics (3,4,6,7).
Other purported benefits of probiotics include reducing lactose intolerance, improving mental health, treating inflammatory bowel disease, reducing the risk of colorectal cancer, combating side effects of radiation therapy and chemotherapy, and improving immune function (2-4,8). However, research in several of these areas is still in early stages or has not found much support. Current knowledge is limited by the fact that this field of research is relatively young, many existing studies were not appropriately designed to be able to provide high quality evidence for either the benefits of probiotics or lack thereof, and the gut microbiome is an extremely rich and complex ecosystem (1,3,4).
Probiotics can be a healthy addition to your nutritional plan. They have known benefits for the digestive system and may have benefits for other areas of health as well. In particular, recent research has found a link between the gut and the nervous system, and one major question in this field is whether probiotics may improve neurological, mental, and/or cognitive health (3,4). Anyone with questions about whether to add probiotics to their nutritional plan should consult a trained professional, such as a dietitian or chiropractor with training in nutrition.
- Mayo Clinic Staff. (2021). “Prebiotics, probiotics and your health.” Mayo Clinic. https://www.mayoclinic.org/prebiotics-probiotics-and-your-health/art-20390058
- Villines, Z. (2018). “What is the difference between prebiotics and probiotics?” Medical News Today. https://www.medicalnewstoday.com/articles/323490
- Sanders, M. E., Guarner, F., Guerrant, R., et al. (2013). An update on the use and investigation of probiotics in health and disease. Gut, 62(5), 787–796. doi:10.1136/gutjnl-2012-302504
- Gareau, M. G., Sherman, P. M., & Walker, W. A. (2010). Probiotics and the gut microbiota in intestinal health and disease. Nature Reviews Gastroenterology & Hepatology, 7(9), 503–514. doi:10.1038/nrgastro.2010.117
- Moayyedi, P., Ford, A. C., Talley, N. J., et al. (2010). The efficacy of probiotics in the treatment of irritable bowel syndrome: a systematic review. Gut, 59, 325-332. doi:10.1136/gut.2008.167270
- Guarino, A., Vecchio, A. L., Canani, R. B. (2009) Probiotics as prevention and treatment for diarrhea. Current Opinion in Gastroenterology, 25(1), 18-23. doi:10.1097/MOG.0b013e32831b4455
- Goldenberg, J. Z., Yap, C., Lytvyn, L., et al. (2017). Probiotics for the prevention of Clostridium difficile‐associated diarrhea in adults and children. Cochrane Database of Systematic Reviews, 12. doi:10.1002/14651858.CD006095.pub4
- Shaukat, A., Levitt, M., Taylor, B. C., et al. (2010). Systematic Review: Effective Management Strategies for Lactose Intolerance. Annals of Internal Medicine, 152(12), 797-803. doi:10.7326/0003-4819-152-12-201006150-00241