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Word of the Day

Daily probiotic with Lactobacillus casei reduces upper RTI duration in elderly

Clinical Question:
Does a fermented probiotic (Lactobacillus casei) reduce the incidence or duration of common acute infections in the elderly?

Bottom Line:
This randomized controlled trial found that acute upper respiratory tract infections (RTIs) in elderly patients taking daily doses of Lactobacillus casei were approximately 3 days shorter than in those taking a control product, though the mechanism remains unclear. (LOE = 1b)

Guillemard E, Tondu F, Lacoin F, Schrezenmeir J. Consumption of a fermented dairy product containing the probiotic Lactobacillus casei DN-114001 reduces the duration of respiratory infections in the elderly in a randomized controlled trial. Br J Nutr 2010;103(1):58-68.  [PMID:19747410]

Study Design:
Randomized controlled trial (double-blinded)



Outpatient (any)

Well, the title pretty much says it all. Previous smaller studies have shown a reduced risk of acute RTI in patients taking Lactobacillus casei, a probiotic. How does this work? Frankly, there is a lot of handwaving and speculation, but no clear or convincing mechanism. Thus, this intervention is a bit of a black box. In this study, 1072 independent-living older French adults were randomized to 200 grams per day of fermented Lactobacillus casei or a nonfermented control product. The mean age of participants was 76 years, and 37% were male. Approximately 80% of patients completed the 4-month study; they took the product for 3 months, and had an additional 1 month of additional follow-up. In the intention-to-treat analysis, there was no significant difference between groups regarding the number of common infectious diseases (respiratory and gastrointestinal illnesses), upper RTIs, or episodes of rhinopharyngitis (ie, the common cold). For example, there were 61 acute upper RTIs in patients taking the fermented product and 66 in the control group. However, the duration of infections was shorter for common infectious diseases (7.4 vs 9.8 days; P = .008) and for acute RTI (7.7 vs 11.0 days; P = .0002). There was no difference between groups in adverse events.


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