Probiotics for the Common Cold?

By Nicolas Peters, MD

Many people have heard about using probiotics for stomach and intestine problems and, in fact, several studies have shown them to be effective in children for treating viral diarrhea and preventing diarrhea that occurs during antibiotic treatment.[1]^,[2] Some experts are even recommending their use for infant colic[3]. Recent research suggests probiotics may even help depression[4]. One area where increasing evidence supports the use of probiotics in children is for the common cold, also known as a viral upper respiratory infection (URI). They have shown promise in not just preventing infections but also in shortening duration of symptoms when children become ill.

URIs are a significant burden to the healthcare system, filling Pediatricians’ offices during fall and winter. They are also an economic strain as family members often have to take off work to care for a ill child.[5] Since they are easily passed from person to person, preschool children are three times more likely to get a URI an infection than those staying at home.[6]

A group of researchers in Washington, DC found that giving a probiotic drink to 3 to 6 year olds in a daycare/school for 90 days had a 20% decrease in URIs compared with children who were not on probiotics.[7]

During the 2010-2011 cold and flu season, 3 to 6 year olds were studied in a preschool in Slovakia and were given a chewable probiotic tablet with vitamin C, or placebo. After the 6 months the probiotic/vitamin C group showed 33% reduction in URIs, an average of 21 days shorter duration of symptoms, 30% decrease in school absences, and fewer days on cough medicine, painkillers, or nasal sprays.[8]

A review out of the UK of eight studies in children found fewer numbers of days absent from day care / school in those who had taken probiotics compared with those who took a placebo.[9]

A study of children attending day care in Finland gave probiotics of placebo for 28 weeks. The children given probiotics experienced cold symptoms on 6 ½ days fewer per month compared to the control group.[10]

In another Finnish study, 1-6 year olds attending day care were given milk with a probiotic for 7 months over the winter. The children showed a 17% decrease in the rate of URIs compared to those who got milk without the probiotic. An unexpected and interesting finding came when the stool of the children was tested for the presence of the probiotic strain. The children who received the probiotic milk had a 79% increase in the probiotic in their stool (as expected), but the control group, who did not receive the probiotic, showed a 11% increase in their stool. This supports what every parent of a preschool child knows: as much as you try to wash their hands, they inevitably share germs with each other.[11]

Recently, a Cochrane review was completed to assess the effectiveness probiotics in preventing URIs. This meta-analysis concluded that in children given probiotics, the odds of getting a URI was 43% less than children who did not take probiotics. When the data was focused on children who experienced 3 URIs that season, the odds improved to a 56% decreased in those received probiotics.[12]

Often, when probiotics are studied in children, only one strain at a time is used. Information suggests combinations of probiotic strains may have an additive or even synergistic effect.[13] One study so far has sought to determine if 2 strains were more effective than one. Children between 3 and 5 years of age attending day care were given probiotic powders 7 days a week for 6 months. The groups that received probiotics had significantly fewer episodes of fever, cough, and runny nose. The double probiotic group showed an improvement to a greater degree than the single probiotic group. The double probiotic group also showed shorter duration of symptoms when they did occur, compared to the control group and compared with the single probiotic group.[14]

As research has shown, a healthy GI tract supported with probiotics can be beneficial in preventing colds and decreasing the duration of symptoms in small children. Much more research is needed to determine the ideal dose and strains of probiotics to use. But in the meantime, chances are good that some probiotics are better than none.