Trusting your gut

Guts are having a renaissance. It’s 2021 and it’s now perfectly acceptable to bring them up in conversation. Look in the bookshop window and the shelves are groaning with guts. The gastrointestinal tract is merely a 4.5 metre tube, yet it’s the most densely populated spot on the planet. A place that 100 trillion microbes call home, housing 300–1000 different species, which together weigh in at around 2kg. That’s heavier than a brain. Our gut biomes are…