Most of those bacterial cells are concentrated in the stomach and intestines--the areas collectively known as the gut microbiome. Up to a thousand different species of bacteria inhabit your microbiome, and (contrary to popular assumption), most of them are actually beneficial to your body, with the disease-causing microbes limited to a minority. Humans have evolved alongside our microbiomes over millions of years in a symbiotic relationship with many benefits.
So what exactly does your gut microbiome do? Among other things, the gut microbiome plays an important role in digestion, particularly of fiber. It also supports the immune system as the bacteria within your body communicate to your own immune cells, instructing them on how to best fight infections.
But although we usually live in harmony with our gut microbes, sometimes imbalances occur. When your body has too many hostile microbes in the gut microbiome and not enough of the friendly bacteria, a state called dysbiosis occurs. This results in conditions like bloating, impaired digestion, and abdominal pain. It's in cases like this that you might want to turn to a probiotic.
So what is a probiotic, exactly? In short, a probiotic is a dose of cultivated good bacteria that are deliberately introduced to the gut microbiome. You can find naturally-occurring probiotics in fermented foods like yogurt, kimchi, kombucha, and sauerkraut--or you can take a probiotic supplement.
Probiotic supplements can vary widely in composition, but they all share a few common traits. On probiotic packaging, you'll see two important numbers. The first number is the total amount of live cultures in the probiotic. This number is usually somewhere in the billions--it might seem like a lot, but the gut microbiome works with a large scale of bacteria. The second number is the amount of strains of cultures. This can range from single-strain probiotics like lactobacillus acidophilus or saccharomyces boulardii to comprehensive probiotics containing a dozen or more strains. You'll also note that many probiotics specify on the packaging whether or not they require refrigeration. Many bacteria are especially sensitive to heat and moisture, and being too hot may actually kill the good bacteria within the probiotics. At Cambridge Naturals, we keep all of our probiotics in the refrigerator, just in case.
Probiotics can be helpful for anyone who experiences unpleasant gut symptoms like bloating or indigestion. They can also help to repopulate the gut microbiome after you've taken a course of antibiotics like penicillin (which kills both the bacteria that cause infection as well as, unfortunately, killing off some of the good bacteria in your body). Probiotics have also been found to aid individuals who suffer from yeast infections--especially a type of probiotic called lactobacillus rhamnosus.
Along with the probiotic cultures themselves, many probiotics come formulated with what's known as a prebiotic. This is a form of plant fiber that nourishes the good bacteria in the gut--it's basically the equivalent of giving them a welcome-home gift.