Those who take part in clinical trials often have to do nasty things, from taking new drugs to forgoing sleep. Participants in a trial organised by Stanley Hazen of the Cleveland Clinic, in Ohio, had a decidedly easier task: eating steak. After reading Dr Hazen’s conclusions, though, they may be inclined to eat rather less of it.
A link between red-meat consumption and heart disease was perceived by epidemiologists several decades ago, but the nature of this link has never been properly explained. Blame’s finger usually points at saturated fats and cholesterol. Red meat contains both. But a big recent study showed no connection between saturated fat and heart disease, so something else is probably involved. Dr Hazen thinks he knows what. As he outlines in a paper just published in Nature Medicine, he believes the blame actually lies with the microbiome—the collection of 100 trillion or so bacteria that live in the human gut.