Probiotics Fail to Cut Respiratory Infections

Probiotics do not appear to reduce the incidence of respiratory tract infections, though they may help reduce the severity and duration of these infections, based on a review of 14 published randomized clinical trials.

“The majority of RCTs [randomized clinical trials] included in this review indicate that the incidence of RTIs [respiratory tract infections] does not appear to be considerably influenced by prophylactic administration of probiotics, although probiotics may have a beneficial role in reducing the severity and duration of subsequent RTIs,” wrote Dr. Evridiki K. Vouloumanou of the Alfa Institute of Biomedical Sciences, Athens, and colleagues.

The study appears in the September issue of the International Journal of Antimicrobial Agents (2009;34.e1-197e.10; [doi:10.1016/j.ijantimicag.2008.11.005]).

Ten of the 14 trials showed no difference in the incidence of RTIs between patients on probiotics and those on placebo. In four of the trials, the incidence of RTIs was significantly lower in those on probiotics.

The authors reviewed RCTs exploring the use of probiotics to prevent or ameliorate RTIs that they identified through a literature search. Databases included PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and SCOPUS. The researchers searched for available trials up to Feb. 5, 2008. They identified 14 studies with 3,580 participants that met their quality criteria (Jadad score greater than 2).

Upper RTIs in the studies included common cold, acute otitis media, tonsillitis/tonsillopharyngitis, sinusitis, and recurrent sinusitis. Lower RTIs included bronchitis and pneumonia. Probiotics used in the trials included Lactobacillus spp., a strain of Bifidobacterium longum, combinations of Lactobacillus and Bifidobacterium species, and a nonpathogenic strain of Enterococcus faecalis. Six of the trials involved healthy children or infants, six included healthy adults, one involved children with RTI, and one involved adults with RTI.

“A significant reduction regarding the severity of symptoms of RTIs associated with probiotic treatment was found in five of six RCTs that provided relevant data,” they wrote. There was no difference in symptom severity in the remaining trial. In addition, three of nine RCTs reported a significant difference in favor of the probiotics groups. However, the other six showed no difference.

In six RCTs, no adverse events were noted that could be attributed to the probiotics. In three RCTs, adverse events of minor severity included nausea, bloating, and diarrhea. In one RCT the development of dyspepsia prompted reduction in the amount of probiotic daily intake. The authors said that they had no conflicts of interest.

Probiotics do not appear to reduce the incidence of respiratory tract infections, though they may help reduce the severity and duration of these infections, based on a review of 14 published randomized clinical trials.

“The majority of RCTs [randomized clinical trials] included in this review indicate that the incidence of RTIs [respiratory tract infections] does not appear to be considerably influenced by prophylactic administration of probiotics, although probiotics may have a beneficial role in reducing the severity and duration of subsequent RTIs,” wrote Dr. Evridiki K. Vouloumanou of the Alfa Institute of Biomedical Sciences, Athens, and colleagues.

The study appears in the September issue of the International Journal of Antimicrobial Agents (2009;34.e1-197e.10; [doi:10.1016/j.ijantimicag.2008.11.005]).

Ten of the 14 trials showed no difference in the incidence of RTIs between patients on probiotics and those on placebo. In four of the trials, the incidence of RTIs was significantly lower in those on probiotics.

The authors reviewed RCTs exploring the use of probiotics to prevent or ameliorate RTIs that they identified through a literature search. Databases included PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and SCOPUS. The researchers searched for available trials up to Feb. 5, 2008. They identified 14 studies with 3,580 participants that met their quality criteria (Jadad score greater than 2).

Upper RTIs in the studies included common cold, acute otitis media, tonsillitis/tonsillopharyngitis, sinusitis, and recurrent sinusitis. Lower RTIs included bronchitis and pneumonia. Probiotics used in the trials included Lactobacillus spp., a strain of Bifidobacterium longum, combinations of Lactobacillus and Bifidobacterium species, and a nonpathogenic strain of Enterococcus faecalis. Six of the trials involved healthy children or infants, six included healthy adults, one involved children with RTI, and one involved adults with RTI.

“A significant reduction regarding the severity of symptoms of RTIs associated with probiotic treatment was found in five of six RCTs that provided relevant data,” they wrote. There was no difference in symptom severity in the remaining trial. In addition, three of nine RCTs reported a significant difference in favor of the probiotics groups. However, the other six showed no difference.

In six RCTs, no adverse events were noted that could be attributed to the probiotics. In three RCTs, adverse events of minor severity included nausea, bloating, and diarrhea. In one RCT the development of dyspepsia prompted reduction in the amount of probiotic daily intake. The authors said that they had no conflicts of interest.

Probiotics do not appear to reduce the incidence of respiratory tract infections, though they may help reduce the severity and duration of these infections, based on a review of 14 published randomized clinical trials.

“The majority of RCTs [randomized clinical trials] included in this review indicate that the incidence of RTIs [respiratory tract infections] does not appear to be considerably influenced by prophylactic administration of probiotics, although probiotics may have a beneficial role in reducing the severity and duration of subsequent RTIs,” wrote Dr. Evridiki K. Vouloumanou of the Alfa Institute of Biomedical Sciences, Athens, and colleagues.

The study appears in the September issue of the International Journal of Antimicrobial Agents (2009;34.e1-197e.10; [doi:10.1016/j.ijantimicag.2008.11.005]).

Ten of the 14 trials showed no difference in the incidence of RTIs between patients on probiotics and those on placebo. In four of the trials, the incidence of RTIs was significantly lower in those on probiotics.

The authors reviewed RCTs exploring the use of probiotics to prevent or ameliorate RTIs that they identified through a literature search. Databases included PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and SCOPUS. The researchers searched for available trials up to Feb. 5, 2008. They identified 14 studies with 3,580 participants that met their quality criteria (Jadad score greater than 2).

Upper RTIs in the studies included common cold, acute otitis media, tonsillitis/tonsillopharyngitis, sinusitis, and recurrent sinusitis. Lower RTIs included bronchitis and pneumonia. Probiotics used in the trials included Lactobacillus spp., a strain of Bifidobacterium longum, combinations of Lactobacillus and Bifidobacterium species, and a nonpathogenic strain of Enterococcus faecalis. Six of the trials involved healthy children or infants, six included healthy adults, one involved children with RTI, and one involved adults with RTI.

“A significant reduction regarding the severity of symptoms of RTIs associated with probiotic treatment was found in five of six RCTs that provided relevant data,” they wrote. There was no difference in symptom severity in the remaining trial. In addition, three of nine RCTs reported a significant difference in favor of the probiotics groups. However, the other six showed no difference.

In six RCTs, no adverse events were noted that could be attributed to the probiotics. In three RCTs, adverse events of minor severity included nausea, bloating, and diarrhea. In one RCT the development of dyspepsia prompted reduction in the amount of probiotic daily intake. The authors said that they had no conflicts of interest.