Probiotics are live microorganisms, typically bacteria or yeasts, that confer a health benefit on the host when administered in adequate amounts. These beneficial microbes are often referred to as “good” or “friendly” bacteria because they contribute to a healthy balance within your digestive system. The gut environment, known as the microbiome, is a complex ecosystem that plays a large role in overall well-being. When the body is fighting an illness, the balance of this microbial community can be disrupted, leading many people to wonder if supplementing with probiotics can help restore harmony during a period of sickness.
Counteracting Antibiotic-Related Digestive Distress
Taking antibiotics is the most common reason people consider using probiotics while sick, primarily to prevent Antibiotic-Associated Diarrhea (AAD). Antibiotics kill harmful bacteria causing infection, but they are not selective and also destroy beneficial gut bacteria. This indiscriminate killing disrupts the normal balance of the gut flora, which often leads to digestive side effects like diarrhea.
Probiotics help restore this microbial balance by introducing new beneficial organisms to repopulate the gut and crowd out potential pathogens. Clinical research shows that co-administering probiotics with antibiotics can reduce the risk of AAD by about 37% to 50% in adults and children. The efficacy is particularly strong for specific strains, such as the bacterium Lactobacillus rhamnosus GG (LGG) and the yeast Saccharomyces boulardii. These strains are consistently found to be effective in preventing AAD, with some studies ranking LGG as having the highest probability of effectiveness.
Higher doses are more effective, with recommendations often starting at five billion colony-forming units (CFU) per day or more. Utilizing a probiotic with proven strains helps maintain the integrity of the intestinal environment. This reduces the chance of severe complications like Clostridioides difficile infection (C. diff), a serious form of antibiotic-related colitis.
Probiotics and General Immune System Support
The gut is highly interconnected with the body’s defense mechanisms, a relationship often termed the gut-immune axis. Probiotics can support the immune system by modulating its response when fighting off various infections. The beneficial microbes strengthen the epithelial barrier of the intestines, which acts as a physical shield against toxins and pathogens entering the bloodstream.
Probiotics also interact directly with immune cells present in the gut lining, influencing their activity. They stimulate the production of protective substances, such as short-chain fatty acids (SCFAs), which help calm inflammation and nourish the gut barrier. These microorganisms enhance the activity of various immune cells, including lymphocytes and macrophages, supporting a more balanced immune response. This support is supplementary, working to optimize the body’s natural defenses, rather than acting as a direct treatment for the illness itself.
Safety Considerations and Proper Usage
For most healthy individuals, taking probiotics alongside antibiotics is safe and well-tolerated, with few reported adverse effects. Proper timing is a practical consideration to maximize the probiotic’s survival and effectiveness. The beneficial microorganisms should be taken at least two to three hours apart from the antibiotic dose to prevent the medication from killing the probiotic organisms. Starting the probiotic within 24 to 48 hours of beginning the antibiotic course offers the best chance for AAD prevention.
It is recommended to continue taking the probiotic for one to two weeks after the antibiotic course is finished to allow the gut flora to fully stabilize. Probiotics are not suitable for everyone, and certain safety warnings must be observed. Individuals who are severely immunocompromised, such as those undergoing chemotherapy, or patients who are critically ill, have a central venous catheter, or have a condition like pancreatitis, should consult a doctor before use. In these vulnerable populations, there is a serious risk of infection from the live organisms in the supplement.