Previous research has indicated that probiotic supplementation may be a promising method to protect against common infectious diseases (CID), which are generally recognized to include respiratory tract infections and gastrointestinal tract infections. The purpose of this systematic review was to assess the effects of consumption of a fermented dairy drink containing L. paracasei subsp. paracasei CNCM I-1518 and standard yogurt cultures (collectively referred to as FDD) on CID. Nine literature databases were searched for studies with the following inclusion criteria: 1) the food studied was FDD, 2) subjects were generally healthy children and adults aged 2 years and older, 3) the study was a randomized controlled trial, 4) incidence, duration or severity of CID was assessed, 5) independent effects could be isolated, and 6) full- text published in English in a peer-reviewed journal. Of the nine studies selected for analysis, two were with in children, three were with adults and four were with the elderly. Combined effect sizes were determined for CID incidence, CID duration, and CID severity. Compared to the control (i.e., non-fermented dairy product), consumption of FDD 1) significantly reduced the odds of experiencing greater than or equal to1 CID (OR = 0.81 (0.66, 0.98); p = 0.029) across three studies conducted in adults and the elderly; 2) significantly reduced mean CID per subject (−0.09 (−0.15, −0.04); p = 0.001) across two studies in adults and the elderly; and 3) showed a trend towards reduced risk in cumulative CID (relative risk (RR): 0.91 (0.82, 1.01); p = 0.082) across four studies in all age groups. No significance was seen on CID duration or severity.
Study strengths: This is the first meta-analysis on probiotics to report outcomes on the effects of an FDD containing L. paracasei subsp. paracasei CNCM I-1518 and standard yogurt cultures. Additionally, absence of confounding variables considered relevant to clinical studies of immune function were applied through three quality criteria using the NIH tool for quality assessment of controlled intervention studies.
Study limitations: This study combined different age groups due to limited data. It should be noted that young children and elderly may be at a higher risk for certain CID. Therefore, results should be interpreted with caution due to a limited evidence base. Additionally, results on subcategories of CID (i.e., upper respiratory tract infections, lower respiratory tract infections) were not reported and should be considered for future meta-analyses. Finally, the FDD studied is present in commercialized products marketed under brand names such as Actimel and DanActive; therefore, the benefits of FDD may not be generalizable to all fermented foods and drinks.
What this means for your practice: The results from this study contribute to the understanding of the beneficial effects of foods and drinks containing L. paracasei subsp. paracasei CNCM I-1518 on CID in the general population. Fermented dairy drinks can be an affordable and nutritious option for the families you care for. Encouraging families to purchase these drinks without added sugar can help kids stay healthy. For more information on healthy drinks, refer your families to www.rethinkyourdrinknevada.com.
Original citation: Poon, T., Juana, J., Noori, D., Jeansen, S., Pierucci-Lagha, A., & Musa-Veloso, K. (2020). Effects of a Fermented Dairy Drink Containing Lacticaseibacillus paracasei subsp. paracasei CNCM I-1518 (Lactobacillus casei CNCM I-1518) and the Standard Yogurt Cultures on the Incidence, Duration, and Severity of Common Infectious Diseases: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients, 12(11), 3443.