Probiotics are healthy organisms, bacteria or yeast, that confer a benefit to humans when they are consumed. Commonly used probiotics include Lactobacillus, Bifidobacterium, and Saccharomyces. Previously, they have been shown to reduce antibiotic-induced diarrhea, yeast infections, and cholesterol levels.
This month, in an early online edition of the British Journal of Nutrition, researchers from New Jersey compared the severity and duration of upper respiratory infections (URI) and number of missed school days between 97 college students receiving probiotics and 104 students who received a placebo. Probiotics included 1 billion colony forming units of each Lactobacillus rhamnosus LGG and Bifidobacterium animalis given for 12 weeks. In those who received probiotics, the median duration of URI was 2 days shorter, the severity of URI was 34% lower, and the number of missed school days was 2 days less than those who received no probiotics.
The authors commented that college students are susceptible to URIs due to poor sleep, stress, and close living quarters. They recommended further study to determine the mechanism of action and the cost and benefits of prolonged probiotic supplementation.