18th November 2009

Confused about probiotics?

The health effects of probiotics have been applauded as 'miraculous' one minute and labelled with 'misleading health claims' in another. Consumers are confused but a new scientific review by the British Nutrition Foundation (BNF), Probiotics and health – summing up the evidence, draws together complex probiotic research and shows accumulating evidence to support the health benefits of probiotics in some areas. The results of this review are a valuable tool for health professionals which will underpin consistent health advice.

The BNF has examined around 100 original research studies and reviews on probiotics and health. Sian Porter, spokeswoman for the British Dietetic Association says: "We welcome BNF’s efforts to bring together the evidence on probiotics and clear the confusion. This review is a useful, up-to-date resource for dietitians to support their evidence based advice on the use of probiotics for different health conditions, to both individuals and the public".

A complex science

‘Probiotics’ is an extremely complex topic, and this often leads to consumers being exposed to conflicting advice. Dr Elisabeth Weichselbaum, Nutrition Scientist and author of the BNF review says: "Probiotics seem to work in a very strain specific manner - speaking about ‘probiotics’ in general may be as misleading as speaking about ‘pills’ and their effects on health. If a certain strain has been found to affect a certain health outcome, such as IBS, it would be misleading to state that ‘all probiotics’ are effective in relieving IBS symptoms."

The BNF review shows that each single probiotic strain has to be tested for each single health outcome. To be effective, probiotics need to influence the balance of the human gut microflora. Probiotics must be able to survive their passage through the gastro-intestinal tract, be taken regularly, and in the right dose. Dr Weichselbaum adds: "Scientists are also now becoming increasingly aware that it is important to test whether the food or drink in which probiotics are given is an effective vehicle for delivering health benefits."

Promise for irritable bowel syndrome

Between 3-25% of the population complains of the uncomfortable symptoms of irritable bowel syndrome (IBS), so it is no wonder that sufferers are interested in whether probiotics can help. Professor Glenn Gibson, Professor of Food Microbiology at the University of Reading, is optimistic: "The science shows promising results for the use of probiotics in IBS. The studies have looked at many different strains of bacteria but we need more studies to find out which strains are most effective, and to make sure any benefits found are not the result of a placebo effect."

Established benefits for diarrhoea

The potential for probiotics to help in the prevention and treatment of diarrhoea has been widely studied.

Antibiotic-associated diarrhoea

Dr Weichselbaum says: "The prevention of antibiotic-associated diarrhoea has a good science-base for some probiotic strains. Two strains called S. boulardii and L. rhamnosus GG have been shown to cut the risk of antibiotic-associated diarrhoea by more than a half."

Dr Mary Hickson, Imperial College Healthcare NHS Trust adds: "Certain strains of bacteria have good evidence to show they prevent antibiotic associated diarrhoea and Clostridium difficile diarrhoea. Providing products containing these strains to hospital patients may help to reduce these detrimental side effects and so reduce healthcare costs".

Infectious diarrhoea

There is also good science to support the treatment of infectious diarrhoea with some probiotics. Dr Weichselbaum says "The probiotic strains S. boulardii and L. rhamnosus GG have been shown to shorten the duration of acute diarrhoea in children, on average by one day. There is also some evidence that other strains may be effective, but more studies are needed to confirm this".

Potential hope for constipation sufferers

Constipation is a very common condition that affects people of all ages. The scientific evidence shows that by altering the balance of bacteria in the gastro-intestinal tract, probiotics could help relieve constipation. Dr Weichselbaum says: "Studies examining the effects of probiotics on constipation are limited. Results for some bacterial strains are conflicting but evidence for some strains - L. casei rhamnosus Lcr35, L. casei Shirota - seems promising, so it is worth encouraging sufferers to try products containing these probiotic strains".

Sara Stanner, Science Programme Manager at the BNF, would like to see more consistent advice to consumers: "although probiotics is a complicated area, we hope that our review explains the issues and shows where the science is heading. Health professionals need to be aware that different probiotic strains are beneficial for different health conditions". To support health professionals, BNF has produced a series of factsheets on probiotics and health, which are available at www.nutrition.org.uk/nutritioninthenews/probiotics.




For further information, interviews and images contact:

Lisa Miles tel: 0207 4046504

Elisabeth Weichselbaum tel: 0207 4046504


Notes to Editors:

  1. For further information see www.nutrition.org.uk/nutritioninthenews/probiotics.
  2. These comments are highlights from a scientific review published by the British Nutrition Foundation: Probiotics and health: a review of the evidence. The review is published in the December issue of the Nutrition Bulletin which is available online 18/11/09
  3. The British Nutrition Foundation offers an expert nutrition information service for journalists and media. Tel: 02074046504. Email: postbox@nutrition.org.uk
  4. The British Nutrition Foundation (BNF) was established over 40 years ago and exists to deliver authoritative, evidence-based information on food and nutrition in the context of health and lifestyle. Accurate interpretation of nutrition science is at the heart of all we do. The Foundation’s work is conducted and communicated through a unique blend of nutrition science, education and media activities. BNF’s strong governance is broad-based but weighted towards the academic community, and we are honoured to have Her Royal Highness The Princess Royal as our Patron. BNF is a registered charity that attracts funding from a variety of sources, including contracts with the European Commission, national government departments and agencies; food producers and manufacturers, retailers and food service companies; grant providing bodies, trusts and other charities.
Last reviewed November 2009. Next review due December 2013.