We contain, on average, around one thousand different species of bacteria inside our guts. And in total: well, it’s difficult to count, but there are trillions. And they are almost all doing useful work for us.
Our genomes contain around 20,000 genes, but our microbes carry around 500 times more. This allows them to perform some pretty awesome tricks – they help digest food, produce vitamins and minerals and even stop us from catching diseases by crowding out and killing infectious bacteria.
But they go even further than that: they have shaped who we are on the inside and out.
Fermented foods are especially good for encouraging a healthy microbiome. “People know about live yoghurts, but the next stage up which has five times as many microbes is kefir, a Persian soured milk,” Spector told me. Other fermented foods like miso soup and kimchi (pickled cabbage) are a delicious feast for your internal lodgers.
If that all sounds a bit rich, then garlic, artichokes, bananas and whole grains are also good fibrous fodder. And the polyphenols in red grapes are one of the favourite meals of Akkermansia. Which I’m taking as a good excuse for another glass of red.