Eat to please your microbiome

All the studies are showing that the greater the variety of microbes we have living inside us, the healthier we will be. And it’s not just about a happy digestion; an unbalanced population of gut flora has been linked to everything from immune trouble to depression to degenerative diseases to cancer. So what happens when we ask the question: what should I eat to please my microbiome?

The first essential ingredient is fibre. It has no nutritional value for us, but the bacteria love it. It’s present in whole vegetables and fruit – though not juice – although our modern vegetables are much lower in fibre than the wild ones we co-evolved with. Root vegetables are the best.

The second ingredient is variety. Different bacteria get to work on different foods (this is why, when you eat an unfamiliar food, you sometimes get an upset stomach; it’s not that the food is bad, just that you don’t have the bacteria to deal with it). So the greater the range you eat, the more diverse your gut flora will be. Estimates vary, but at least 17-21 different vegetables and fruits per week seems to be a good start.

The third ingredient is fermented foods, which contain lots of bacteria to replenish your supply and add useful new ones. Many foods are fermented, from bread and alcohol to tofu, sauerkraut, yogurt, kimchi and kefir, and a few surprises like chocolate. Most of the bacteria don’t make it through to your gut, but some do, and fermentation makes food much easier to digest. Expect tastier versions of some traditional fermented products to appear on the market any time soon, but beware; if it’s blander, it probably has a much smaller load of lovely bacteria.

The fourth ingredient is an interesting one: fasting. When you don’t eat for several hours, a different set of microbes goes into action, cleaning up the gut wall. You don’t have to do extended fasts or even regular days of not eating, but going without from time to time is beneficial to gut health.

And last of all: what foods do not please your microbiome? No surprises here. Processed food, sugar and sweeteners, and high fat ‘junk’ food all tend to lead to a reduction in the number and variety of bacteria. If your bacteria are happy, then you will be happy, so it makes sense to limit consumption of this last group.