Eat colourful vegetables. In fact it is recommended to eat vegetables of 5 different colours every day. But why different vegetables of different colours? One of the reasons is that this variety is good for the bugs that live in our gut, and their associated genes, collectively known as our microbiome. Scientists have only recently begun focusing on this area, and it’s becoming clear that the importance to our mental and physical health of having a healthy microbiome can hardly be overstated. And we have a lot of these bugs to feed. One study found that the human gut contains between 30 trillion and 400 trillion microorganisms, whereas the number of actual human cells in our bodies ranges from 5 trillion to 724 trillion. ‘Based upon these approximations,’ write the scientists, ‘the human body could have nearly the same amount of cells as microbes, or at the more extreme end, non-human cells may outnumber our own almost a hundred to one.’

Whilst researchers are discovering more about these bugs every day, there is still much that’s unclear. Our best guess at the moment is that an ideal microbiome is a diverse one, capable of adaptation and job share. These bugs have evolved with us over millions of years and live off the food we take in and, in return, provide a huge array of services to the human machine. For example, one species makes serotonin, which is the hormone linked with your mood. Others manufacture vitamins.

Over the years our gut populations have been decimated by modern industrial living, food additives, high stress levels, the overuse of antibiotics and much more.

A recent examination of the Hadza, a Tanzanian hunter-gatherer tribe, suggested that our gut’s microbiome is 50 per cent less diverse than theirs. This could be a key factor in growing rates of chronic, degenerative diseases. If we have a greatly diminished microbiome, it also might explain why we are no longer able to tolerate certain foods. Our microbiome represents a key component of our body’s defence system against the outside world.

FEEDING YOUR MICROBIOME

There is a simple way we can start fixing our damaged microbiomes. We’re forever being told that vegetables are good for us, but it’s not often explained why. Well, here’s one of the key reasons – because our gut bugs love plant-based fibre. This is also known as pre-biotic fibre. Broccoli is a particularly fine example. When the fibre that’s in broccoli gets as far as your large bowel, or colon, it finds itself in the place where the vast majority of your gut bugs live. They feast on it and produce various by-products including short-chain fatty acids, or SCFAs. These SCFAs, including the most studied one, butyrate, are anti-inflammatory.This means that they help bring down the inflammation and its harmful effects, including heart disease, stroke, Alzheimer’s disease.

BUILDING UP YOUR IMMUNE SYSTEM

Because the body is so interconnected, by feeding the microbiome we’re also strengthening other parts of it, such as our immune system. It’s common to think of the immune system as something that is there simply to protect us from airborne bacteria and viruses and prevent coughs and colds. Whilst that’s true, 70% of our immune system activity takes place in and around our gut. This makes perfect sense, of course, because our gut is one of the key interfaces between the external world and our bodies.

FOODS FOR YOUR GUT BUGS

Our ancestors ate between 50 and 150 grams of complex fibre per day – that is about 10 times the amount that most people eat today! These complex fibres are known as Microbiota Accessible Carbohydrates (MACs) because they are carbohydrates that feed our gut bugs. They’re found in abundance in vegetables but also in fruits and legumes. We can’t use them directly as they are hard to break down and digest. But our gut bugs can!

Getting five different vegetables into your diet every single day will accelerate the process of optimizing your microbiome. To enhance the benefits even further, try to make these vegetables as many different colours as you can. This means it’s much more likely that you will encourage the growth of more beneficial bacteria as well as getting maximum gut-bug diversity.

Different colours contain different phytonutrients. Red foods, such as tomatoes, contain lycopene, which some researchers argue reduces the risk of some types of cancer and heart disease. Orange foods, such as carrots, contain beta-carotene, which has a beneficial effect on our immune system and promotes healthy vision. Green vegetables, such as broccoli, contain chlorophyll, which seems to help control hunger. The list goes on. Some vegetables, lentils and fruit are listed below. Try to eat 5 different colours everyday