Knight says probiotic marketing outpaces microbiome evidence

Marketing and startups continue to sell the potential of probiotics and other microbial applications rather than what scientific research has already established, Rob Knight, a professor at the University of California in San Diego, told ERR. He said microbes could eventually contribute to improving both human health and the environment.

Five points from Rob Knight

The prebiotic and probiotic market remains like the Wild West. Although probiotics have proven benefits for several indications, research is still far from demonstrating broad health benefits. Fortunately, the bacteria found in most supplements are generally weak enough not to harm people.

Uniform training data undermine precision medicine algorithms. Models trained on one population group can fail when used with others. Diagnostic systems should be fine-tuned using data from local biobanks to avoid situations in which a solution treats patients in the same way as a soap dispenser calibrated for white skin treats Black people.

Science relies on open access to raw data to correct itself. Reproducible results require researchers to share their raw data and analysis code freely. However, the current academic career model makes organising and cleaning data feel like tedious housekeeping, reducing the long-term value of costly research.

General dietary rules are incomplete without personal data. Conventional wisdom and universal recommendations, such as advising people to eat plenty of fruit, can sometimes harm health. Ideally, dietary advice should be personalised and based on multiple data streams, including the microbiome and changes in blood sugar levels.

Society celebrates rescuers but undervalues prevention. Maintaining health is always far more effective than trying to reverse an illness after it has developed. Yet most healthcare funding goes towards rescue efforts aimed at treating what is already broken.

“I am naturally sceptical of all kinds of marketing claims,” Knight said. He recalled watching with dismay as different prebiotic and probiotic products appeared on shop shelves from the 2010s onwards, promising to improve people’s health with their various bacteria.

According to Knight, probiotic marketing has always been far ahead of the evidence. He said the situation had not improved over the years because of several structural reasons.

At the same time, there is enough evidence that probiotics can help with several indications, he said. He cited diarrhoea following a course of antibiotics and certain forms of irritable bowel syndrome as classic examples in which specific probiotic products may help people.