Gut Feeling

Probiotics Research Indicates Good Bacteria Can Conquer Bad

It’s a balancing act that you feel in your gut.
More than 400 types of bacteria—good and bad—live in the digestive system and help break down food. A settled stomach and smooth elimination attest to a healthy balance. But excess bad bacteria—caused by factors including alcohol, stress, disease and exposure to toxins—can set the stage for upset stomachs, diarrhea and other problems.

“People mostly get diarrhea by being exposed to viruses or bacteria and ingesting them,” says Dr. Scott Martin, a professor in the Medical College of Georgia Department of Physician Assistant. “They may touch something that’s been exposed to these bacteria and viruses, then wipe their eyes or nose and eventually become ill. Contaminated food is another source of infection.”

But good bacteria, he says, can conquer the bad.

Probiotics, or healthy bacteria, combat digestive problems by competitive exclusion, Dr. Martin says.

“The good bacteria out-compete the bad and bind to the intestines to keep the bad from attaching and causing the illness. Consequently, the bad organism gets flushed out of the gastrointestinal tract.”

Probiotics also counter the complications of antibiotics, which don’t differentiate between good and bad bacteria. “Because they kill both types of bacteria, not just the disease-causing ones, antibiotics leave us susceptible to harmful organisms that can cause yeast infections and diarrhea,” Dr. Martin says. “People taking antibiotics often counter those effects by taking a probiotic supplement or eating yogurt that contains live cultures.”

Indeed, he notes, yogurt’s health benefits have long been considered no-brainers. But only recently have many of those benefits been traced to probiotics, which are added to foods including yogurt and sauerkraut to speed the fermentation process. Probiotics are also available in a pill form and can be purchased at most pharmacies.

“We haven’t even begun to identify all of the bacteria—good and bad—in the human body,” Dr. Martin says. “But we do know now that good bacteria prevent bad bacteria from surviving and multiplying, which has obvious positive health effects.”

Most probiotic research has focused on two forms of nonpathogenic bacteria—lactobacilli and bifidobacteria—because probiotics occur naturally in the colon and are used in the fermentation process to make yogurt. But as the research advances, evidence suggests that more health benefits will be uncovered.

“There is some early evidence that probiotics may hold promise as a way to prevent colon cancer and other diseases, but we don’t have enough research to prove that right now,” he says.

--Jennifer Hilliard