'Good' Bacteria Aid Weight Loss Surgery

Study Shows Probiotics Improve Weight Loss and Lessen Nausea After Weight Loss Surgery

Reviewed by Louise Chang, MD on May 21, 2008

May 21, 2008 -- A bacteria pill a day may enhance weight loss among obese people undergoing gastric bypass surgery.

Researchers studied 42 morbidly obese people who had weight loss surgery. Six months after surgery, those who took a daily probiotic supplement had shed 70% of their excess pounds vs. 66% for those who did not.

Study participants who took probiotics after surgery also had less nausea and bloating and generally felt better than those who did not, says researcher John M. Morton, MD, of the Stanford School of Medicine.

"It's a very safe, cheap, and easy-to-administer adjunct to weight loss surgery," he tells WebMD.

The findings were presented at Digestive Disease Week 2008 in San Diego.

Too Much of a Good Thing

The study is the latest to point to the health benefits of probiotics, or so-called good bacteria. Found in certain yogurts and supplements, probiotics are often used to treat diarrhea and other gastrointestinal ailments.

We all have hundreds of species of bacteria in our digestive tract. They help to digest sugars and other carbs. Many are thought to help prevent illness by keeping other, sickness-causing microbes from flourishing.

But sometimes you can have too much of certain bad bacteria, Morton says. That can cause gastrointestinal symptoms, which can affect quality of life.

After noticing that some patients who had undergone gastric bypass surgery had elevated levels of bad bacteria, he decided to see if probiotics could restore the balance of good to bad bacteria in the GI tract.

Patients in the study were given a supplement that contained 2.4 billion colonies of Lactobacillus daily.

Probiotics Lower Levels of Harmful Bacteria

At six months, breath tests confirmed the patients taking supplements had lower levels of harmful gastrointestinal bacteria than those who didn't. The test measures hydrogen byproducts that are produced when bacteria digest carbohydrates.

Morton says that the fact that patients taking supplements had less nausea and bloating could have contributed to their extra weight loss.

"If you're able to digest food with more comfort, you may be less likely to seek out junk food after surgery," he says.

Alternately, the changes in weight could have been directly due to the changes in bacteria levels, Morton says.

Gastroenterologists are enthused about the approach. "Even though it's a small study, I would recommend the supplements to patients who experience GI symptoms after surgery," says Mark DeLegge, MD. DeLegge, professor of medicine at the Digestive Disease Center of the Medical University of South Carolina in Charleston, who moderated a media briefing to discuss the findings.

But, he cautions, patients shouldn't start taking supplements on their own; always check with your doctor first.

Gastric Bypass Surgery

During gastric bypass surgery, surgeons create a smaller stomach pouch, which dramatically reduces the amount of food a person can eat. In addition, a portion of the small intestine is attached to the pouch to allow the food to bypass the rest of the stomach and the upper portion of the small intestine; this cuts calorie and some nutrient absorption.

Morton says that the procedure has revolutionized the care of morbidly obese patients who can't get the pounds off with diet, exercise, and medication. "There's striking weight loss, about 80% at one year. In 82% of patients, it cures diabetes. And there's resolution of hypertension and other medical problems. The benefits clearly outweigh the risk."

But there are risks -- and one that most people don't want to talk about is stool incontinence. At the meeting, other researchers reported that it often gets worse, not better, after weight loss surgery.

University of Wisconsin researchers surveyed 194 patients who had undergone bariatric surgery: 159 underwent gastric bypass surgery and 35 had gastric banding.

Among the findings:

  • About half of patients had stool incontinence, usually in the form of uncontrollable diarrhea, before the surgery. About half of them thought it got worse after surgery.
  • Nearly three-fourths of patients suffered from urinary incontinence before the procedure. Of those, two-thirds reported either an improvement or no change following the procedure.

DeLegge says patients need to tell their doctors if they are experiencing incontinence. For diarrhea, the physician may prescribe extra fiber or medications that make the stool more solid, he says. In some cases, biofeedback can help, DeLegge adds.

Show Sources


Digestive Disease Week 2008, San Diego, May 18-21, 2008.

John M. Morton, MD, department of surgery, Stanford School of Medicine.

Mark DeLegge, MD, professor of medicine, Digestive Disease Center, Medical University of South Carolina, Charleston.

Erica Roberson, MD, department of internal medicine, University of School of Medicine and Public Health, Madison.

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