Pediatric applications of probiotics

Probiotics for allergic diseases: realities and myths

The prevalence of allergic diseases such as asthma, allergic rhinitis, and atopic dermatitis has increased sharply over the past two to three decades in many countries, and allergies are now the most common chronic disease among children throughout the world. In the past few years, probiotics have been advocated for the management of allergic diseases in many parts of the world. Physicians have a responsibility to ensure the efficacy and safety of any products they prescribe or recommend. This article provides a comprehensive overview and a critical interpretation of currently available evidence regarding the role of probiotics in the prevention and treatment of allergic diseases in humans and also discusses several major myths and potential risks associated with the use of probiotics. In the current era of evidence-based medicine, there is still insufficient evidence to recommend probiotics for the prevention of allergic diseases or as part of standard management for any allergic conditions in children.

Use of probiotics in pediatrics: rationale, mechanisms of action, and practical aspects

The use of probiotics (ingested microbes that can modify intestinal microbial populations in a way that benefit the host) has moved from concept to actual demonstration of specific benefits by specific microorganisms for specific populations. It is increasingly clear that these benefits to the host are mostly mediated by the profound effect that intestinal microflora (microbiota) have on gut barrier function and host immune response. Intestinal bacteria are more numerous than the human cells of the host that harbors them. Despite having many potential pathogens in this microflora, humans do not routinely get infected. It is no coincidence that gut-associated immune tissue constitutes approximately 80% of all immunologically active cells in the human host. The gut interacts with intestinal bacteria, both resident and ingested, to develop protective mechanisms (via improving gut barrier function and immune stimulation for defense) and appropriate, nonexaggerated responses (via immune modulation and immune tolerance) to support host health. The mechanisms of this interaction between host and bacteria are increasingly being unraveled and in great part explain the clinical benefits that have been reported with specific probiotic bacteria by enhancing host defense mechanisms (such as for treatment and prevention of viral diarrhea and reducing risk of necrotizing enterocolitis), mitigating antibiotic-associated diarrhea, and modulating host immune response (such as in allergic disease).

Probiotics in the prevention and treatment of gastrointestinal infections

Probiotics have been studied in a variety of GI infections, and are an appealing concept given their favorable safety profiles. Several placebo-controlled trials indicated that lactobacilli have a suppressive effect on H pylori infection. Although some studies reported improvement in H pylori eradication, others failed to confirm this. Controlled trials support the use of Lactobacillus GG and S boulardii for the prevention of AAD, and have demonstrated the effectiveness of S boulardii as adjunctive therapy for RCDAD. Several placebo-controlled trials showed a reduction in the severity and duration of acute diarrhea in children with use of Lactobacillus GG. Studies of probiotics for the prevention of traveler's diarrhea yielded conflicting results, and their routine use cannot be recommended in this setting. Preliminary evidence suggests a potential role for reducing secondary pancreatic infections, although conclusive evidence is not available at this time. Additional clinical trials are indicated to define the role of probiotics further before wide-spread use can be recommended.