Prospective study of probiotic supplementation results in immune stimulation and improvement of upper respiratory infection rate

Abstract

The human gut microbiota is an important environmental factor for human health with evolutionarily conserved roles in immunity, metabolism, development, and behavior of the host. Probiotic organisms are claimed to offer several functional properties including stimulation of immune system. The purpose of this study is to investigate the effects of a probiotic supplementation on adult volunteers who have contracted the common cold four or more times in the past year. This study is a single center, double-blind, randomized, controlled, prospective trial. Subjects received a probiotic drink containing Lactobacillus paracasei (at least 3 × 107 colony forming units (CFU) ml−1), Lactobacillus casei 431® (at least 3 × 107 CFU ml−1) and Lactobacillus fermentium PCC® (at least 3 × 106 CFU ml−1) or an identical placebo without probiotics for a 12-week study period. The consumption of probiotics significantly reduced the incidence of upper respiratory infection (p < 0.023) and flu-like symptoms with an oral temperature higher than 38 °C (p < 0.034) as compared to the placebo group. Subjects that consumed probiotics demonstrated a significantly higher level of IFN-γ in the serum (p < 0.001) and sIgA in the gut (p < 0.010) as compared to the placebo group and a significant higher level of serum IFN-γ (p < 0.001) and gut sIgA (p < 0.001) as compared to their baseline test results. In contrast, there were no significant differences in the serum IL-4, IL-10, IgA, IgG or IgM between the probiotics and the placebo groups. Results of this study demonstrated that probiotics were safe and effective for fighting the common cold and influenza-like respiratory infections by boosting the immune system.

Positive metabolic effects of selected probiotic bacteria on diet‐induced obesity in mice are associated with improvement of dysbiotic gut microbiota

“…Large numbers of microbes have been found in the GI tract, and play a critical application in maintaining immune homeostasis in the gut microenvironment. 54,55 The Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) stated that probiotics are live microorganisms, which supplemented in sufficient amounts; confer a health benefit to the host. 17,56 The health benefits of probiotic strains vary largely but provide significant benefits to the human health, such as utilization of nutrients, resistance to infections, the management of intestinal microbial diversities, immune system development, and host metabolic regulation.…”

Role of probiotics to combat viral infections with emphasis on COVID-19

“…The human nose and upper respiratory tract efficiently hold the pathogen through invading immunogenic particles and droplets. The pathogen detected by mucosal layers of the gastrointestinal tract (GI), respiratory, urinary, and genital tracts functions as the body's immunologic system (Zhang et al 2018). The human nose is covered by type 1 mucosal layer consisting of a single layer of epithelial cells, antigenpresenting cell, goblet cells, and specialized lymphoid organs similar to the gastrointestinal tract.…”

The potential application of probiotics and prebiotics for the prevention and treatment of COVID-19

“…Probiotic supplements containing L. paracasei, L. casei, and L. fermentum significantly reduced the incidence of influenza-like symptoms and upper respiratory infection in adults, who commonly experience colds ≥4 times per year. Treated adults exhibited significantly higher interferon (IFN)-γ levels in serum and higher soluble IgA levels in the GI tract than untreated adults or their own baseline results 74 .…”