DEAR DOCTOR K: Lately I've noticed a lot of TV ads for probiotic products, especially yogurt. What do they do? Should I start eating them?
DEAR READER: Our bodies are home to a mix of “good” and “bad” bacteria. Most of them live in our intestines, but there are bacteria flourishing in many parts of our bodies. You can't see them — they're just along for the ride.
Sometimes bad bacteria that do not normally live in our gut gain entrance, usually in the foods we eat or liquids we drink. These invaders can rapidly cause diseases such as “turista,” cholera, typhoid fever and C. difficile infection.
Unlike the invaders, the bad bacteria that probiotics are designed to fight normally live in the gut. Hundreds of different species of good bacteria help digest your food. Under balanced conditions, these friendly bacteria outnumber the bad bacteria. We're beginning to learn that the bad bacteria living in our gut may help cause a number of different diseases if they are able to throw the bacterial balance out of whack.
Infection, for example, can make your gut more vulnerable to unfriendly bacteria. Probiotics are “good” living bacteria that you ingest to improve the balance of bacteria.
One thing that commonly throws off the balance of bacteria in the gut is taking antibiotics for some kind of infection elsewhere in the body. Along with killing that infection, the antibiotics often kill good bacteria. This can lead to gas, cramping or diarrhea. Probiotics can help offset the bacterial imbalance caused by taking antibiotics.