Probiotics and the Innate Immune System

Introduction: The innate immune system, also known as nonspecific immunity, encompasses the body's inherent physiological defense mechanisms. It responds to the invasion of various pathogens and foreign substances, providing a generalized immune response. Certain structural components of probiotics, such as peptidoglycans, when absorbed into the bloodstream through the digestive tract, can directly stimulate the body's innate immune system, enhancing the activity of innate immune cells like phagocytes, natural killer cells (NK cells), and dendritic cells. Consequently, the benefits of probiotics in activating the innate immune system extend beyond the digestive system, impacting overall nonspecific immune functions.

Probiotic Supplementation and Respiratory System Disorders: Research conducted by Cox et al. indicates that a 14-week intake of fermented lactobacilli (VRI-003) significantly reduces the duration and severity of symptoms associated with respiratory infections when compared to a placebo. This suggests that probiotic supplements can enhance the immune function of the respiratory system, thereby shortening the course of respiratory infections. Michalickova et al.'s double-blind randomized controlled trial (RCT) also found that a 14-week intake of fermented lactobacilli (Lafti L10) significantly reduces the duration of upper respiratory tract infections compared to a placebo. Another RCT by Salarkia et al. discovered that an 8-week consumption of probiotic yogurt reduces the frequency of respiratory infections, respiratory difficulties, and enhances maximal oxygen consumption during exercise in female swimmers.

Furthermore, studies have delved into the proportions and dosages of probiotic supplements for preventing respiratory infections. Clinical research has shown that supplementing with a combination of Plantarum HEAL9 and Bifidobacterium lactis at a ratio of 8700:2 has a synergistic effect, effectively reducing the frequency, duration, and severity of cold symptoms. Berggren et al.'s double-blind RCT demonstrated that a 12-week intake of this probiotic combination, with a ratio of 8700:2 and a dosage of 10^9 CFU/d, significantly reduces overall cold symptom scores, especially those related to throat symptoms. This indicates that the specific ratio and dosage of probiotics have an immunomodulatory effect, helping to prevent colds.

Conclusion: In conclusion, the interaction between probiotics and the innate immune system plays a crucial role in enhancing overall nonspecific immune functions. Probiotic supplementation, particularly in specific proportions and dosages, shows promise in mitigating the severity and duration of respiratory infections, providing a potential avenue for improving immune health and preventing common illnesses.