William P. Hanage in Nature:
Explorations of how the microscopic communities that inhabit the human body might contribute to health or disease have moved from obscure to ubiquitous. Over the past five years, studies have linked our microbial settlers to conditions as diverse as autism, cancer and diabetes. This excitement has infected the public imagination. 'We Are Our Bacteria', proclaimed one headline in The New York Times. Some scientists have asserted that antibiotics are causing a great 'extinction' of the microbiome, with dire consequences for human health1. Companies offer personalized analysis of the microbial content of faecal samples, promising consumers enlightening information. Separate analyses from the same person can, however, vary considerably, even from the same stool sample. Faecal transplants have been proposed — some more sensible than others — for conditions ranging from diabetes to Alzheimer's disease. With how-to instructions proliferating online, desperate patients must be warned not to attempt these risky procedures on themselves. Microbiomics risks being drowned in a tsunami of its own hype. Jonathan Eisen, a microbiologist and blogger at the University of California, Davis, bestows awards for “overselling the microbiome”; he finds no shortage of worthy candidates. Previous 'omics' fields have faltered after murky work slowed progress2. Technological advances that allowed researchers to catalogue proteins, metabolites, genetic variants and gene activity led to a spate of associations between molecular states and health conditions. But painstaking further work dampened early excitement. Most initial connections were found to be spurious or, at best, more complicated than originally believed.
The history of science is replete with examples of exciting new fields that promised a gold rush of medicines and health insights but required scepticism and years of slogging to deliver even partially. As such, the criteria for robust microbiome science are instructive for all researchers. As excitement over the microbiome has filtered beyond academic circles, the potential mischief wrought by misunderstanding encompasses journalists, funding bodies and the public. Here are five questions that anyone conducting or evaluating this research should ask to keep from getting carried away by hype.