Probiotics Not as safe as believed to be

By Vibha Varshney
Published: Monday 31 March 2008

-- it's believed that probiotics--dietary supplements containing microbes--benefit health. A recent study dispels the notion and says they may adversely affect patients suffering from acute infection in the pancreas, called pancreatitis. Probiotics strengthen the natural microflora--yeast and bacteria--in the body and the researchers hoped that this trait would help cure pancreatitis. But they were proved wrong. Mortality increased in patients who were administered probiotics, said 'probiotics in pancreatitis trial', the largest ever study on probiotics.

The researchers from the department of surgery, University Medical Center Utrecht, The Netherlands, studied 298 patients; 153 received a pro-biotic preparation of lactobacilli and bifidobacteria and the rest got a placebo. The doses were administered twice a day for 28 days and the variety of infections in patients was observed twice; during admission and the second after three months.The following were the results of the study

Down to Earth 30 per cent of those on probiotics suffered infectious complications compared to 28 per cent in the placebo group

Down to Earth 16 per cent of the patients in the probiotics group died; the mortality rate in the placebo group was 6 per cent

Down to Earth Nine patients in the probiotics group developed bowel ischaemia, of whom, eight died; no one in the placebo group suffered the problem

The research team concluded that in patients with acute pancreatitis, the probiotic strains given did not reduce the risk of infectious complications. "Our findings show probiotics should not be administered routinely in patients with predicted severe acute pancreatitis, and that the particular composition used here should be banned. Probiotics can no longer be considered to be harmless adjuncts to enteral nutrition," the authors noted in the paper published in February 23 issue of The Lancet.

But how do probiotics, which have been associated with positive developments so far, affect pancreatitic patients? "Severe pancreatitis is associated with increased gut permeability and giving probiotics in that condition is counterproductive as probiotics leak across the breached intestinal barrier to gain entry into the blood stream and cause sepsis. Hence, they are not a good idea for critically ill patients with breached intestinal barrier function," says G E Mullin, Division of Gastroenterology, Johns Hopkins Hospital, Baltimore, us.

The deaths during the trial are being investigated by the Dutch Healthcare Inspectorate and the Central Committee. The scientific evaluation has prevented the ad hoc and widespread adoption of probiotic therapy, based on anecdotes and personal bias, said Derek A O'Reilly and Andrew N Kingsnorth, professors of surgery, Derriford Hospital, Plymouth, in a comment in the British Medical Journal.

Large-scale effect The larger question is how the results will impact the millions of people worldwide who regularly consume probiotics in various forms--baby food, curd, ice creams and health drinks. Marc Besselink, the lead author of the paper, says the results do not have any relevance on the general use of probiotics. "Given the obvious fact that people buying over-the-counter probiotics do not suffer from acute pancreatitis there is no problem," he says. An editorial in The Lancet says the results intensify the debate over the role of probiotics as nutritional supplements. This has implications for the global probiotic market of about us $4 billion. The microbes are naturally present in fermented food. Those who promote probiotics say natural food do not have the same degree of predictability and reliability that probiotics do.

The eu requires scientific evidence to support claims of benefit but it is often found that labelling is misleading. Despite Food and Agriculture Organization's recommendations to specify strain details, number of viable bacteria and storage conditions, a uk survey in 2006 revealed that half of the probiotics tested did not adhere to them. The Lancet editorial suggests that questions on safety and efficacy should lead to further research on probiotics, including community studies.

Johannes Huebner, assistant professor of Medicine, Harvard Medical School, Boston, us, told Down To Earth that while there is growing evidence to support specific preparations, it is also important to be aware of risks associated with probiotic treatments, especially in seriously ill and immuno-compromised patients. "Probiotics should be under stringent quality control required for drugs instead of being treated as food additives," says Huebner.

Subscribe to Weekly Newsletter :

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.