Study suggests probiotics carry no benefits for healthy adults

A review of existing studies has indicated there is “no convincing evidence” that probiotic food and drink carry benefits for healthy people.
The team of researchers in Denmark analysed seven randomised, controlled trials of probiotic products, all of which had involved healthy adults between the ages of 19 and 88 years, with each sample size containing between 21 and 81 people. The studies had investigated whether the microbial composition of a healthy adult’s faeces had experienced changes as a result of consuming probiotics.
For time periods of 21 to 42 days, the study teams administered probiotic products in the form of capsules, sachets, biscuits and milk-based drinks. Reviewing these studies, the Danish researchers did not identify any changes to the microbial composition, indicating that probiotics failed to have any effect on the healthy adults.
The researchers admitted that larger sample sizes would be needed before saying for certain that probiotics do not work, but based on the current evidence it looks like people may be wasting their money on these kinds of products. One study did suggest changes to the microbial composition, but this may have been an anomaly, the researchers claimed.
Probiotics are often heavily marketed as products which improve your health, fighting infections and improving digestion, as well as carrying other benefits.
Probiotics are defined as “live microorganisms which confer a health benefit to the host if administered in adequate amounts,” by the World Health Organisation (WHO). However, the findings by the Danish team challenge this current definition.
Professor Oluf Pedersen, senior author, said: “While there is some evidence from previous reviews that probiotic interventions may benefit those with disease-associated imbalances of the gut microbiota, there is little evidence of an effect in healthy individuals.”
“To explore the potential of probiotics to contribute to disease prevention n healthy people there is a major need for much larger, carefully designed and carefully conducted clinical trials.”
“These should include ideal composition and dosage of known and newly developed probiotics combined with specified dietary advice, optimal trial duration and relevant monitoring of host health status,” he continued.
The findings were published in the journal Genome Medicine.