However the news was not all bad. The meeting was also occasion for the positive results of a subset analysis conducted at Ireland's Alimentary Pharmabiotic Centre (APC) at University College Cork to be presented.
Involving 165 women with IBS, the study indicated that in the 85 who received B. infantis 35624 for four weeks as opposed to a placebo, the probiotic showed promise in normalizing bowel movements - both in those suffering from constipation and those with diarrhoea.
IBS is a long-term condition that usually involves abdominal discomfort accompanied by diarrhoea or constipation. It is believed to affect more than 58 million people worldwide, and more women suffer from it than men. Although it is not life threatening and dose not lead to other, more serious health conditions, IBS is untreatable. At present, intervention involves management of symptoms.
Strict regulations around the world mean that probiotic products cannot carry explicit disease prevention or treatment claims, but they are often marketed as containing 'friendly' or 'good' bacteria that can redress the balance of flora in the gut and help the user to feel 'better'.
The same UCC team, led by Professor Eamonn M.M. Quigley, reported in the in the March issue of Gastroenterology (vol 128, issue 3, pp541-51) that patients who consumed a malted milk drink containing B. infantis 35624 everyday for eight weeks experienced fewer overall symptoms, abdominal pain and discomfort than those taking a placebo.
The symptom relief was comparable to that seen with Zelnorm (tegaserod) and Lotronex (alosetron), drugs that have been recently approved for the treatment of irritable bowel syndrome (IBS).
B. infantis 35624 is not presently available in commercial products, but the APC works in partnership with Procter and Gamble and is hoping to bring the bacteria to market in new products.
Overall, the two review studies were less ebullient in their findings.
One, conducted at the Mayo Clinic, looked at probiotics' observed ability to improve bloating in seven randomized, controlled trials. They concluded that the studies showed only a modest improvement, but said that there is a need for larger trials.
Similarly, investigators from the University of New Mexico reviewed eight clinical trials looking at safety and efficacy of probiotics in IBS, and found that there was a great deal of variation in results.
"We found that various probiotic regimens may be useful in IBS, but larger trials are needed to verify findings from the smaller studies we analyzed," said lead researcher Dr Paveen Roy.