Croup, the common cold, tonsillitis, and sinus infections (1-5). Although generally mild and short-lived, we all want to avoid them and the disruptive symptoms they bring (1). Besides being unwelcome, what do these conditions have in common? Well, they are all types of acute upper respiratory tract infections (URTIs), which happen to be a significant source of illness. Children and older adults are especially vulnerable to acute URTIs (1-5).
The number of upper respiratory infections seen each year is substantial. In 2019 alone, there were 17.2 billion new cases across the globe (2). The question then becomes, is there anything we can do to protect ourselves from getting them?
Probiotics, considered “good” bacteria that promote gut health, have been a strategy of interest for the prevention of respiratory tract infections for many years. Their consumption, via foods containing them or supplements, is also rising. A recent systematic review updated the evidence base on whether probiotics can thwart the development of acute URTIs in children, adults, and older adults with a healthy immune system (1).
What the research tells us
Compared with a placebo or no treatment, probiotics—most often consumed with milk‐based food, via capsules, or through a powder formulation in this review—show the potential for several benefits in people with healthy immune systems.
First, probiotic consumption may lower the number of people diagnosed with at least one URTI and probably decreases the number diagnosed with at least three URTIs. Second, when it comes to how long an “episode” of acute URTIs lasts, probiotics my decrease the average duration by around 1.22 days (1). With the overuse of antibiotics having a significant role in the growing issue of antibiotic resistance, here we see that probiotics may also decrease the number of people who use prescribed antibiotics for an acute URTI (1;6;7). Last but not least, in comparison to placebo or no treatment, probiotics are most often associated with minor side effects such as gassiness, bowel pain, vomiting, and diarrhea (1).
Overall, our confidence in these findings ranges from low to moderate. More high-quality studies that feature a greater number of participants are needed to increase our certainty in these results and our understanding of the potential effects, especially in older adults (1).
If you are considering probiotics as a preventative strategy against acute URTIs or in general, remember to consult your health care team first. Together you can discuss the different ways probiotics can be consumed and choose the best and safest option for you.