Conventional wisdom tells us bacteria are bad, causing colds, infections and other unpleasantries. And that's true — the wrong kinds of microbes in the wrong circumstances can indeed cause problems.

However, that's only part of the story.

The rest of the story is that bacteria can also be beneficial — in fact, bacteria can even help us become healthier. The trillions of bacteria that live inside our bodies are collectively called the microbiome, which is present at birth and becomes further diversified as we grow. Most of these bacteria live inside the large intestine, which contains up to 1,000 different strains of bacteria.

While some gut bacteria are harmful, most of them play an essential role in our health and survival. Research shows these microorganisms help us digest food, fight infection and maintain a healthy weight. Some scientists even speculate that gut bacteria may have an effect on how our brain works, as well as the health of our heart. Having the right balance of "good" and "bad" bacteria in your gut is thought to be one of the keys to maintaining good health.

What Happens When You Don't Have Enough "Good" Bacteria?

Life happens. Sometimes we get sick, don't get enough sleep or eat too much sugary, processed food. We may experience stress from work and relationships, or take antibiotics that destroy healthy gut bacteria. All of these things can throw our gut microbiomes out of whack, decreasing levels of good bacteria in our digestive system and increasing levels of bad bacteria. When your gut microbiome is out of balance, your body doesn’t function as it should—and you may not feel your best. For example, an imbalanced microbiome can affect the formation of healthy stools. It may also make you more vulnerable to colds and infections.

Probiotics to the Rescue

Probiotics are live, “good” bacteria that, when ingested, may help replenish the gut microbiome with healthy microbes that your body needs to thrive. Probiotics can be found in foods like yogurt, sauerkraut and kefir, although only in small amounts. Rather than consume large quantities of these foods, many people choose to supplement their diet with probiotics, which are much more convenient and provide highly concentrated doses of healthy bacteria.

A high-quality probiotic can help increase the naturally beneficial flora in your gut, which in turn supports your body’s ability to perform at its peak.

With so many probiotics on the market today, choosing the right probiotic supplement can be tricky.