A recent study suggests that probiotics might reduce the duration of respiratory infections in both adults and children.
Probiotics are beneficial bacteria (sometimes referred to as "friendly germs") that help to maintain the health of the intestinal tract and aid in digestion. The normal human digestive tract contains about 400 types of probiotic bacteria. The largest group of probiotic bacteria in the intestine is lactic acid bacteria, of which Lactobacillus acidophilus, found in yogurt, is the best known. Other types of probiotics include different strains of Bifidobacterium. Most probiotics come from food sources, especially cultured milk products. Probiotics can be consumed as capsules, tablets, beverages, powders, yogurts, and other foods.
In a new study, researchers conducted a comprehensive literature search in eight databases, including Cochrane Central Register of Controlled Trials (CENTRAL) and MEDLINE, for well-designed studies evaluating the effects of probiotics, specifically Lactobacillus and Bifidobacterium strains, on the duration of respiratory infections in adults and children. Of the 20 studies identified for inclusion, 12 were noted as having a low-risk for bias.
Through data analysis, the researchers found that people who took probiotics were sick for significantly fewer days and were absent from work or school significantly less than those who did not. The authors concluded that the overall body of evidence from well-designed studies suggests that taking probiotics reduces the duration of respiratory infections in otherwise healthy adults and children.
King S, Glanville J, Sanders ME, Fitzgerald 1, Varley D. "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 2014 Apr 29:1-14.