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Probiotics: A Newer Way to Get Through the Winter

shutterstock_106241129With winter just around the corner—and with COVID 19 still hovering in the background—we all are starting to think about what we can do to stay healthy over the next few months. One of the best answers may come from a surprising place: the world of bacteria and probiotics. Probiotics are defined as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.”   Many different bacteria—and even some yeasts-- are now being used as probiotics, available in all different forms including capsules, liquids and powders. Lactobacillus acidophilus is one of the most commonly used, which is why you sometimes may hear the term “acidophilus” used to describe all probiotics. 


But what could bacteria have to do with helping us fight off winter viruses? Well, as it turns out, studies show that taking regular probiotic supplements can help in both preventing upper respiratory infections (URIs) and treating them once they do happen. The first study to show this was way back in 2009, in which 326 children aged 3-5 were given either a probiotic supplement or a placebo twice a day for six months. Amazingly, the kids who got the probiotics had 72% less fevers, 58% less episodes of rhinorrhea or runny nose, 32% less days absent from child care, and an over 89% reduction in use of antibiotics over the study period. Even more amazingly, this finding has been repeated in 13 studies of over 3700 people—both children and adults—with a combined decrease of 50% in the risk of URI.  And another review which looked at a total of 20 different studies found that when people did get a URI, the duration of the cold on average was a full day less in people taking probiotics.


So why, you are thinking, do these bacteria actually help us fight off colds? Well, no one knows for sure yet—but what we do know is that over thousands of years, humans have evolved to depend on “friendly” bacteria for all kinds of functions, digestive and otherwise. The current thinking is that there is a lifelong “conversation” taking place between the probiotic bacteria we live with and our immune system, which helps regulate the immune system to make it more effective in identifying and addressing unfriendly microorganisms. This symbiotic relationship is what appears to be at the root of the fact that probiotics can definitely help protect us against upper respiratory viruses.


The typical dose of a probiotic supplement is in the range of 5-10 billion CFU (colony forming units) per day range for children and 10-20 billion/day for adults, but doses can vary widely between products and a much wider range can still be effective. Side effects are extremely uncommon and when they do occur are typically minor with gastrointestinal symptoms being the most common. There are many brands and formulations of probiotics on the market; some of them are single strains of bacteria, others are combination. We do not have definite evidence which is best, but it does seem that the combination products might be a bit better for URI prevention. You can get some probiotics from yogurt, which does have live bacterial cultures, but the number of bacteria in a typical serving of yogurt is not high enough to reliably have this preventive effect, unless you choose one of the “therapeutic” yogurts which have extra probiotics added. To find a good brand of probiotics, you may want to consider brands including Jarrow, Nature’s Way, or Culturelle, or you can check on for a detailed report of which brands are highest in quality.


Just to be clear, we do not have evidence that probiotics are specifically effective against COVID-19, so taking them should not be seen as a substitute for all the other important steps we are taking for prevention. That said, why not try this for your family and see if taking these friendly bacteria can help you all stay healthier though the winter this year!


1. Kligler B, Hanaway P, Cohrssen A. Probiotics in Children. Pediatric Clinics of North America. 2007.54 (6); 949-967.

2. Leyer GJ, Li S, Mubasher ME, Reifer C, Ouwehand AC. Probiotic effects on cold and influenza-like symptom incidence and duration in children. Pediatrics. 2009 Aug;124(2):e172-9. doi: 10.1542/peds.2008-2666. Epub 2009 Jul 27. PMID: 19651563.

3. Hao Q, Dong BR, Wu T. Probiotics for preventing acute upper respiratory tract infections. Cochrane Database of Systematic Reviews 2015 (2); Art. no.: CD006895. DOI: 10.1002/14651858.CD006895.pub3.

4. Sarah King, Julie Glanville, Mary Ellen Sanders, Anita Fitzgerald and Danielle Varley (2014). Effectiveness of probiotics on the duration of illness in healthy children and adults who develop common acute respiratory infectious conditions: a systematic review and meta-analysis . British Journal of Nutrition, 112, pp 41-54. doi:10.1017/S0007114514000075.



Dr._KliglerDr. Kligler is the Medical Advisor for The Deirdre Imus Environmental Health Center®. He is also the National Director of the Integrative Health Coordinating Center for the Veterans Health Administration and Research Director for the Office of Patient Centered Care & Cultural Transformation. He was the founding  Director  of the Beth Israel Fellowship Program in Integrative Medicine, and teaches in the Beth Israel Residency Program in Urban Family Practice. Dr. Kligler is the author of Curriculum in Complementary Therapies: A Guide for the Medical Educator, and co-editor of Integrative Medicine: Principles for Practice, a textbook published by McGraw-Hill. He is also Co-Editor-in-Chief of the peer-reviewed journal Explore: The Journal of Science and Healing.


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