For GI experts, evidence mounting for probiotics

Mounting evidence is building a strong case for the use of probiotics, or "good" bacteria, to alleviate common gastrointestinal (GI) symptoms, such as diarrhea, bloating, and inflammation, according to several studies highlighted at the American College of Gastroenterology 2011 Annual Scientific Meeting.

Researchers found that in studies covering 3000 patients, probiotic prophylaxis significantly reduced the odds of developing antibiotic-associated diarrhea and Clostridium difficile–associated diarrhea by about 60%. In another trial in which more than 3000 patients received a single or a combination of antibiotics for various indications, the preventive effect of probiotic use was significant, regardless of the species used and regardless of the antibiotic administered.

In the largest study to date on probiotics in a nonpatient population, researchers evaluated the efficacy of Bifidobacterium, a probiotic that has relieved symptoms in patients with irritable bowel syndrome, to see how well it relieved abdominal discomfort and bloating in nonpatients. The double-blind randomized placebo controlled study was conducted on more than 300 nonpatients who had experienced abdominal discomfort and bloating more than twice weekly, on average, for at least 3 months. They had not seen a physician or received prescribed mediation for their symptoms in the previous 12 months. "By giving a specific probiotic orally, we could actually reduce the levels of these proinflammatory cytokines and actually enhance the production of an anti-inflammatory cytokine, which is the exact replication of what we identified in animal models and more basic models," said the researchers. Plasma levels of the anti-inflammatory cytokine interleukin (IL)-10 rose significantly in healthy volunteers and patients with psoriasis, but not in those who took the placebo for 8 weeks. Plasma levels of 2 proinflammatory cytokines — tumor necrosis factor-alpha and IL-6 — dropped in all patients who received Bifidobacterium. C-reactive protein levels were also significantly lower in patients with psoriasis, ulcerative colitis, and chronic fatigue after treatment with the bacterium than after treatment with placebo.

"It's ironic that we would worry about taking an organism when we've got billions of organisms in the GI tract" and the amount is relatively small, researchers observed. Instead of worrying about drug toxicity in that population, "we're worried about something that has vanishingly low side effects. It can't be zero, but it is very, very low." "If we paid more attention to prescribing antibiotics, we wouldn't have a lot of these problems," added researchers.

Bonnie - this is big-time stuff coming from a conservative organization like the ACG.