Probiotics are good bacteria. They can restore the biodiversity within the microbiome, fight pathogenic organisms and help heal the gut mucosa. Healthy people should include a few tablespoons of fermented foods, which are rich in probiotics, in their daily diet. Foods like sauerkraut, kimchi, kombucha, microalgae, tempeh and miso soup and good sources of probiotics. Probiotics should not be confused with prebiotics.
Probiotic supplements can be useful for some gastrointestinal disorders. Some strains have been shown to improve symptoms in antibiotic-associated diarrhea, infectious gastroenteritis, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and hepatic encephalopathy. For antibiotic-associated diarrhea or infectious gastroenteritis, several Lactobacillus strains as well as the probiotic yeast S. boulardii are helpful. For IBS patients, a Bifidobacteria strain (Align) has been shown to improve symptoms. For ulcerative colitis patients, VSL#3, a multi-strain probiotic, has been shown to be helpful.
While probiotic supplements are marketed for broad use, it’s important to remember that the science is still young. Research has shown that in most cases, short-term use of some probiotic supplements probably isn’t too helpful for healthy adults. Supplements are also not subject to the FDA’s standard safety testing as drugs are. That being said, if you are going to take a probiotic supplement, try to pick a reliable brand that has been studied in clinical trials, and take doses with colony-forming units in the billions.
Probiotic supplements are generally well-tolerated by most people. But they need to be used with caution in the immunocompromised, and should be avoided in the severely immunocompromised. Because they contain live bacteria, probiotic supplements can cause dangerous infections in people with weakened immune systems, such as chemotherapy and organ transplant patients.
Excessive use of probiotics can lead to problems. Because the supplement industry is not strictly regulated, contamination with unwanted fillers or pathogenic organisms is a concern. Clinical cases of a condition known as D-lactic acidosis have been reported, and patients with short bowel syndrome who have had much of their gastrointestinal tracts removed or patients with carbohydrate intolerances may be especially at risk. You should take probiotics as directed on the bottle or as prescribed by your doctor.