That matters because lots of probiotic supplements focus around one or two strains – and not all strains are going to work for you. For a start, how do you know which types of bacteria are already thriving in your gut and which you could do with having more of?

It all depends on your gut community. “Some people just don’t have a community that’s going to be receptive to this new guy [the probiotic supplement] coming in and telling them what to do… whereas fermented foods give you a much broader choice. You’ve got all these microbes that are happy living together in the food and, collectively, they’re going to have a better chance of having an effect on your gut and restoring it to health.

“We know from other stories and randomly controlled trials on fermented foods that getting four or five little portions a day in a few weeks can reduce inflammation and boost your immune system. So there’s now science behind these fermented foods.”

Here’s why Dr Tim Spector recommends fermented foods over expensive probiotics for repairing gut health