<i>E. coli</i> and gut health—For the loser now will be later to win

In humans, commensal gut bacteria participate in a miniature nitrogen cycle, metabolizing dietary nitrate and nitrite. While these processes can generate harmful N-nitrosamines, they may also produce beneficial nitric oxide (NO) or ammonium. Hager and colleagues demonstrate that E. coli, though representing less than 1% of the gut flora, plays a dominant role in reducing nitrate and nitrite in the gut, potentially detoxifying carcinogenic intermediates by converting nitrite to ammonium. Their findings reveal a beneficial facet of a bacterium otherwise often linked to disease.