UK food supplements cannot be marketed as probiotics currently (although NICE and the NHS use the term) because no food supplement has been able to satisfy EU health claim labelling requirements. Reasons for this include that a microorganism is insufficiently specified, or that the proposed claims are not specific, measurable or considered a beneficial physiological effect for the target population.37

Probiotic microbes are generally considered safe but they still carry a risk of causing serious adverse events, with septicaemia a theoretical risk in people with serious underlying disease. Particular care is needed with:9,38

·       premature infants;

·       people with a serious illness;

·       the immunocompromised (eg HIV, cancer, or immunosuppressants);

·       long-term corticosteroid therapy;

·       severe pancreatitis;

·       a shortened bowel or experiencing short bowel syndrome.

To reduce risk, the European Food Standards Agency approves which microbes are suitable for food products and supplements. Products containing live organisms should also conform to microbial impurity tests, although impurity levels are not always set for every potential pathogen.38,39

Dose needs to be considered as it does not always follow that a probiotic consumed at a higher dose will have a greater health benefit compared to a lower dose. ISAPP recommends that the dose of a preparation should match the level found in efficacy studies to be beneficial.9

Prebiotics lack any official dietary recommendations for ‘healthy’ individuals, but ISAPP suggests most prebiotics need minimum daily doses of 3g to show an effect, while FOS and GOS prebiotics typically require a minimum of 5g a day.22