The term "probiotics" is thrown around and loosely defined as a health supplement, but the ambiguity surrounding it leads to confusion of the purpose of probiotics in our bodies.
The truth of the matter is that probiotics are live microorganisms that can give their hosts (our bodies) health benefits. These microorganisms, which are mostly bacteria and yeast, are actually alive and functioning in our intestines. When you hear the word "bacteria" you may think of antibiotics and antibacterials, both of which kill bacteria, so why would you want to consume something that has bacteria in it? The key is balance. (via MedicineNet)
What it boils down to is that there are good bacteria and bad bacteria in our guts, and a balance between the two is necessary for a healthy digestive tract and immune balance. According to MedicineNet, the bacteria in our immune system protects us from imbalances that can cause allergic reactions, autoimmune disorders (like Crohn's disease) and infections. An imbalance in the gastrointestinal tract could lead to urinary tract infections, diarrhea, muscle pain and fatigue, so obtaining that balance of bacteria in our guts is crucial to avoid those symptoms.
An imbalance is usually caused by something in our lifestyle like poor food choices, lack of sleep, emotional stress, antibiotic overuse and other drug abuse. The good news is that we hold the power to fix that imbalance as well. And if we can't drastically change our lifestyle, then we can turn to probiotics to help us balance the bacteria in our gut and immune system.
Probiotic products contain bacteria and/or yeast that assist in restoring the balance in our gut. The most commonly ingested probiotic products are capsules or food. Foods like yogurt, cereal, juice, frozen yogurt and granola are said to contain probiotics. However, there is no guarantee that they have the probiotics necessary for health benefits. Only manufacturers can tell you if there are any specific studies related to the probiotics in their products. (via MedicineNet)
Because probiotics are supplements, they are not strictly monitored by the FDA. Some studies show health benefits to taking probiotics, but more research needs to be done in order to ensure that they are safe and effective in food. Children, elderly people, those with compromised immune systems and pregnant women should be careful when taking probiotics. As always, consult your doctor before taking any supplements that are not heavily researched.