Probiotics in Kids: What Is the Evidence?

Maria R. Mascarenhas, MBBS


July 31, 2018

Editorial Collaboration

Medscape &

Hello. I am Dr Maria Mascarenhas, the medical director of the integrative health program and a pediatric gastroenterologist at the Children's Hospital of Philadelphia. I am delighted today to be speaking with you on the topic of probiotics.

What are probiotics? Probiotics are nonpathogenic, live microorganisms that have a positive effect on host health when consumed in adequate amounts. Although probiotics have been around for a long time, it is only recently that we have become more aware of their many health benefits.

Mechanisms of Action

I would like to begin by talking about what probiotics do. We know that probiotics produce an antimicrobial effect by modifying the microbiome and secreting antibacterial substances, such as immunoglobulin A. Probiotics compete with pathogens to prevent adhesion to intestinal epithelium and also compete for nutrients; they produce an antitoxin and have an antioxidative effect; they can reverse infectious complications, secretory changes, and neutrophil migration in the intestinal epithelium; and they modulate the immune system by regulating allergic immune cell response.

Because probiotics are present in many food sources, we do not really need to take a probiotic supplement. Some common foods sources that contain probiotics are yogurts with live, active cultures; kefir; fermented pickles; sauerkraut; kimchi; sourdough bread, which is an excellent source of probiotics; soy beverages; tempeh; and miso.

If you think about it, for centuries probiotics have been a dietary component in most cultures. Having grown up in India, yogurt is a key part of the majority of the population's diet, the exception being those who have a milk allergy.

Beneficial Effects

There is emerging evidence of the beneficial effects of probiotics [in the prevention and treatment] of many conditions. I am going to divide these conditions into two groups: gastrointestinal (GI) and nongastrointestinal/extraintestinal diseases.

Acute and chronic gastrointestinal conditions in which probiotics have been shown to have a beneficial effect include infectious gastroenteritis, antibiotic-associated diarrhea, Clostridium difficile, necrotizing enterocolitis, inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), infantile colic, Helicobacter pylori, and constipation.[1,2,3]

Probiotics also have been shown to have beneficial effects on extraintestinal disorders, such as atopic dermatitis, food allergies, allergic rhinoconjunctivitis, asthma, critical illness (especially ventilator-associated pneumonias), urinary tract infections, and types 1 and 2 diabetes mellitus.[1,4,5] Moreover, studies of probiotics in animal models have demonstrated an antiobesity effect, primarily through anti-inflammatory pathways wherein there is improved oxidative stress and energy homeostasis is modulated.[6]

With respect to the use of probiotics as a preventive for acute infectious gastroenteritis, studies show a modest significant in the research effect but no clinical benefit to their use.[7] As a treatment, probiotics have shown nice effect in patients with acute infectious gastroenteritis. In addition, preventive and treatment benefits of probiotics have been seen in patients with antibiotic-associated diarrhea, as well as patients with IBD and ulcerative colitis (especially for pouchitis).[1] At this time, probiotics currently do not appear to have any effect in treating patients with Crohn disease. There are emerging data demonstrating the beneficial effects of probiotics on IBS and infantile colic.[1,8]

Adverse Effects and Contraindications

There are some adverse effects associated with probiotic use, primarily bloating and flatulence,[1] both of which decrease with continued use. Patients experiencing adverse effects may scale back on the probiotic dose and then gradually increase it as side effects abate, or they may maintain the recommended dose and work through these symptoms. Other adverse effects that have been reported include constipation and increased thirst and more significant issues such as bacteremia, fungemia, sepsis, and endocarditis.[9,10]

Severe adverse effects can be seen primarily in patients who are immunosuppressed. Factors that predispose patients to more significant side effects are any prior hospitalization, severe underlying comorbidities, underlying disease, and central line catheters. Therefore, in our [gastroenterology] practice, we do not prescribe probiotic supplements to patients who have a central line catheter, who are on immunosuppressive medications, or who have any immune defect without first speaking with their primary immunologist.

Safety Profile

There are many studies supporting the safety of probiotics in patients in whom no contraindications exist, such as those predisposed to infection. In fact, several randomized controlled trials demonstrated the safety of probiotics in more than 6000 premature infants.[11]

As you can see, probiotics have many benefits, and the evidence to support their use is increasing. I hope that you have enjoyed this.