Consumers are increasingly aware of the health impact of COVID-19 infection, and its association with the severe acute respiratory syndrome. They are also paying closer attention to how nutrition could impact their health. According to a review article—published in the Nutrition Research Journal (DOI: https://doi.org/10.1016/j.nutres.2020.12.014)—probiotics could play a critical role in supporting respiratory function in the face of viral infection. Lactobacillus (L.) and Bifidobacterium (B.) represent two common strains mainly known to consumers for balancing the gut microbiota and improving digestive health. This review analysed probiotic-related studies published within the last 10 years (between 2010-2020).
The results of this in-depth analysis showed that probiotic strains could help boost immune response to viral-related infections, including, but not limited to, COVID-19. Commenting on the findings from human clinical trial-related studies, the researchers highlighted that certain combinations of probiotics— L. paracasei, L. casei 431, and L. fermentum PCC— halved common flu-like and cold symptoms, causing no side effects. Consumers who were already suffering from respiratory infections had their quality of life drastically improved following L. rhamnosus GG and B. lactis Bb-12 probiotic strain consumption for 12-weeks, with infection severity decreasing by 34% compared to the control group. Meta-analysis results also reported in the review confirmed these findings.
Studies in middle-aged and older adults reported yoghurt containing L. paracasei N1115 bacteria lowered diagnosis rates of respiratory tract infections. Further, L. casei strain Shirota-fermented milk significantly reduced infection rates (infection rate at 22.4%) compared to the control group (infection rate at 53.2%).
In infant studies, participants given L. rhamnosus GG and B. lactis Bb- 12 supplementation daily until they became 12 months old had reduced recurrences of respiratory infections. Further, newborns given B. animalis subsp. lactis BB-12 probiotic strain twice daily for eight months also had lower lung infection rates than the control group.
The research reviewers, out of the CSIR-Institute of Microbial Technology and Academy of Scientific and Innovation Research (AcSIR) in India, noted “improving/strengthening human host immunity is one of the best prophylactic approaches to reduce the severity of such viral diseases.” This paper emphasises the importance of reviewing the literature and exploring new opportunities, whilst staying mindful of regulatory considerations, updates, and product benefit claims. With the benefits of probiotics supplementation to aid viral infections being backed by the extensive literature provided in this review, this is an exciting opportunity for the nutraceutical industry to keep up with all the bacterial strains’ new findings and benefits noted among various strains combination.