You are what you eat!
The lining of your gut, like every surface of your body, is covered in microscopic creatures, mostly bacteria. These organisms create a micro-ecosystem called the microbiome, it plays an oversized role in your health and can even affect your mood and behavior.
There are two ways to maintain this balance — helping the microbes already there to grow by giving them the foods they like (prebiotic) and adding living microbes directly to your system (probiotic).
Prebiotics are specialized plant fibers. They act like fertilizers that stimulate the growth of healthy bacteria in the gut.
Prebiotics are found in many fruits and vegetables, especially those that contain complex carbohydrates, such as fiber and resistant starch. These carbs aren't digestible by your body, so they pass through the digestive system to become food for the bacteria and other microbes. The list of prebiotic foods is long, from asparagus to yams.
Probiotics are different in that they contain live organisms, usually specific strains of bacteria that directly add to the population of healthy microbes in your gut.
Like prebiotics, you can take probiotics through both food and supplements. Probably the most common probiotic food is yogurt, others like sauerkraut, kombucha and kimchi, are also good sources of probiotics. Probiotic supplements also contain live organisms.
Keep in mind
One thing to understand about supplements is that there are many kinds. For instance, one type of bacteria commonly used is lactobacillus. But there are more than 120 species of lactobacillus, and at least a dozen of them are used as probiotics. And even when you select one kind of bacteria, the amount in the supplement can vary between brands.
When taking a probiotic, research the condition you wish to address and select the probiotic based on that condition. Also, keep in mind that while a probiotic may show promise in treating a condition, it's likely that the research is still in early stages.
While the supplement may have improved a condition for a few people in a very limited circumstance, it may not work as well in real-world settings. As always, when considering taking a supplement, talk to your doctor first.