How feeding your gut bacteria could make you happy

Certain “happy” bugs thrive in our digestive systems when we are in good mental health, and are depleted when depressed, according to a recent study on more than a thousand Flemish humans.

Scientists have discovered that a subdivision of bacteria called Coprococcus is usually high in happy people and low in depressed. This means that growing this bacteria in our guts could help support our mental health.

The scientists discovered the difference between happy and depressed people's guts by looking at the bacteria in subjects’ stool samples and comparing them with quality of life questionnaires.

Our digestive system is connected to our brains via a long cord called the vagus nerve, and our gut bacteria pass messages up the line to the brain. Increasing evidence suggests they influence mood. Messages are also passed down from brain to gut - hence that butterfly feeling when we're nervous.

The scientists concluded that the next step in the research trail should be to find out which pills could be developed to plant these “happy” live bacteria into depressed people’s guts.

I read this paper and wondered why some elements of the medical world have to make life complicated and commercial? Why turn to developing a pill when the answers are often so much closer to home, cheaper, and enjoyable?

You just need to ask, which foods do we need to eat to stimulate the growth of a big variety of bacteria in the gut and in doing so increase chances of growing happy ones. And here you have your answer – prebiotic foods.

Prebiotic foods are plants – vegetables, fruits, nuts, seeds, that can’t be digested in the top half of the digestive system. Their textural fibres and/or pigment colours make it all the way down to the colon (the last department before the end) undigested and act like fertiliser on the microbiome (our gut bacteria), stimulating growth of all sorts of beneficial bacteria including Coprococcus.

Interestingly, Coprococcus produces a fuel called butyrate which helps keep your gut lining healthy and helps lower inflammation in the body. Some types of depression are now understood to have an inflammatory component which adds another layer to this story.

Often people I meet in my clinic work are feeling down – low mood often goes hand in hand with gut dysfunction. It’s that gut-brain connection at play.

I also notice that people when busy, stressed and low often find it hard to make good food choices. The typical busy exec diet goes something like this: croissant and coffee, sandwich, biscuits, pasta and tomato sauce washed down with alcohol at the end of the day.

I know this diet well – it was mine when I was a journalist in my past life and I always acknowledge my old friend when I meet it again on food diaries.

Notice something about this diet?

Very beige. Hardly any fibrous textures and different colours.

My tip: If you change just one thing in all this to get the gut and brain symptoms improving it’s this:

Feed your gut bacteria some plant fibre and colour every day to stimulate growth of a diverse range of bacteria including your Coprococcus.


This is my current quickest solution, my Happy Gut Shake:

• 200ml of hazelnut milk (because it tastes nice – you could choose any nut milk you like).

• Stir in one large tablespoon of prebiotic ground flax seeds (you can buy these ready-ground everywhere nowadays including Aldi and all the main supermarkets). Flax seeds, also known as linseeds, are a fabulous source of fertiliser for gut bacteria and improve constipation or loose stools pretty quickly in many people, as well help grow your beneficial bacteria.

• Eat an apple (which contains prebiotic pectin fibre) or a banana (which contains inulin prebiotic fibre) alongside. Or some berries which contain dark colours which are prebiotic.

You can have these at any time of the day for effect.

Of course you may not be able to change some of the bigger problems in your life but feeding your gut some fibre and colour whatever else goes wrong in your day, could help you cope better by getting some happy bugs flourishing to support your brain through the maze of life.



Valles-Colomer M, Falony G, Darzi Y, et al. (2019). The neuroactive potential of the human gut microbiota in quality of life and depression. Nat Microbiol. doi: 10.1038/s41564-018-0337-x.