Research into the human microbiome may offer insights into many aspects of human health and disease, and certainly the discovery of the vastness and diversity of microbial populations that call the human body home have been a surprise, but it may time to tamp down the exuberance a notch, William Hanage, an associate professor of epidemiology at the Harvard School of Public Health, writes in Nature.
"Microbiomics risks being drowned in a tsunami of its own hype," he says, and points to Jonathan Eisen, who gives awards for "overselling the microbiome" on his blog .
Not surprisingly, the media is at least partly to blame, Hanage says, but so are new companies that offer to provide personalized analyses and enlightening information from fecal samples.
"As excitement over the microbiome has filtered beyond academic circles, the potential mischief wrought by misunderstanding encompasses journalists, funding bodies, and the public," he writes.
So, how can researchers and the public avoid feeding the microbiome-industrial-hype-machine? Hanage offers five questions that should be asked concerning microbiome research.
Is it possible to detect differences in the microbiome that actually matter? Microbial genomes are "littered with clues both true and false," he writes, and until it is possible to identify functional differences in closely related genes it is important to remember that seeming similarities between species "might cloak important differences."
Does a study show causation or correlation, he asks. "Sometimes, a particular microbiome found in association with disease will be merely a bystander."
Asking what the mechanism behind causation and correlation also is important, Hanage says, and that a reductionist approach is "essential" to nail down whether the microbiome affects health, and how that works.
Another issue is whether or not experiments reflect reality, he says, noting that microbiome studies often rely on germ-free mice that are not representative of the animals' natural states.
Lastly, when looking at microbiome research results showing that bacteria are linked to a disease it is important to ask whether anything else beyond bacteria could explain the illness.
Hanage says the "hype machine" is dangerous, for people who might make bad decisions and for science. "Press officers must stop exaggerating results, and journalists must stop swallowing them whole," he adds.