Good morning. I’m Dr. Maria Mascarenhas, medical director of the Integrative Health Program and pediatric gastroenterologist at Children’s Hospital of Philadelphia. I am delighted today to discuss the topic of probiotics with you.
What are probiotics? Probiotics are live, non-pathogenic microorganisms that have a positive effect on the health of the host when consumed in adequate quantities. Although probiotics have been around for a long time, it is only recently that we have become aware of their many health benefits.
Mechanisms of action
I’d like to start 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 the intestinal epithelium and also enter into competition for nutrients; they produce an antitoxin and have an antioxidant effect; they can reverse infectious complications, secretory changes and neutrophil migration in the intestinal epithelium; and they modulate the immune system by regulating the response of allergic immune cells.
Since probiotics are found in many food sources, we don’t really need to take a probiotic supplement. Some common food sources containing probiotics are yogurts containing live, active cultures; kefir; fermented pickles; Sauerkraut; Kimchi; sourdough bread, which is an excellent source of probiotics; soy drinks; tempeh; and miso.
If you think about it, probiotics have been a dietary component in most cultures for centuries. Growing up in India, yogurt is a key part of the diet for the majority of the population, with the exception of those with milk allergies.
Benefits
There is emerging evidence for the beneficial effects of probiotics (in the prevention and treatment) of many conditions. I will divide these conditions into two groups: gastrointestinal (GI) diseases and non-gastrointestinal/extra-intestinal diseases.
Acute and chronic gastrointestinal conditions in which probiotics have demonstrated a beneficial effect include infectious gastroenteritis, antibiotic-associated diarrhea, Clostridium difficilenecrotizing enterocolitis, inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), infantile colic, Helicobacter pylori, and constipation.(1,2,3)
Probiotics have also been shown to have beneficial effects on extraintestinal disorders, such as atopic dermatitis, food allergies, allergic rhinoconjunctivitis, asthma, critical illnesses (especially ventilator-associated pneumonia) , urinary tract infections and diabetes mellitus types 1 and 2.(1,4,5) Furthermore, studies of probiotics in animal models have demonstrated an anti-obesity effect, mainly through anti-inflammatory pathways in which oxidative stress is improved and energy homeostasis is modulated.(6)
Regarding the use of probiotics as a preventative measure against acute infectious gastroenteritis, studies show a modest and significant effect in terms of research, but no clinical benefit linked to their use.(7) As a treatment, probiotics have shown a beneficial effect in patients with acute infectious gastroenteritis. Additionally, the preventative and therapeutic benefits of probiotics have been observed in patients with antibiotic-associated diarrhea, as well as in patients with IBD and ulcerative colitis (particularly for pouchitis).(1) Currently, probiotics appear to have no effect in treating patients with Crohn’s disease. New data demonstrates the beneficial effects of probiotics on IBS and infantile colic.(1,8)
Adverse effects and contraindications
There are some side effects associated with probiotic use, primarily bloating and flatulence.(1) both of which decrease with continued use. Patients experiencing side effects can reduce the dose of probiotics and then gradually increase it as side effects subside, or they can maintain the recommended dose and overcome these symptoms. Other reported side effects include constipation, increased thirst, and larger problems such as bacteremia, fungemia, sepsis, and endocarditis.(9,ten)
Serious adverse reactions may be observed mainly in immunocompromised patients. Factors that predispose patients to greater side effects include any prior hospitalization, serious underlying comorbidities, underlying disease, and central lines. Therefore, in our (gastroenterology) practice, we do not prescribe probiotic supplements to patients who have a central line, are taking immunosuppressive medications, or have an immune defect without first discussing it with their primary immunologist.
Security profile
Numerous studies support the safety of probiotics in patients in whom no contraindications exist, such as those predisposed to infections. In fact, several randomized controlled trials have demonstrated the safety of probiotics in more than 6,000 premature infants.(11)
As you can see, probiotics have many benefits, and the evidence supporting their use is growing. I hope you enjoyed this.
