Photo by Hal Gatewood on Unsplash
In short: Your gut and your brain are in conversation all day long, through nerves, hormones and the bacteria living in your gut. That’s why stress can upset your stomach, and why an unhappy gut can leave you feeling flat or on edge. You can support that conversation with plenty of plants and fibre, a little fermented food, regular meals, calm moments to eat, good sleep and gentle movement.
You have a difficult phone call to make. Before you’ve even picked up the phone, there it is: a knot in your stomach. Or perhaps you’re about to speak in front of people, and suddenly you need the loo. Or after a stressful week, your digestion is all over the place, bloated one day and sluggish the next, and nothing you eat seems to sit quite right.
We say “I’ve got butterflies”, “I had a gut feeling”, “it made me sick to my stomach”. Our language has known for a very long time what our bodies feel every day: the belly and the mind are deeply connected. In this article I’d like to explain, in plain words, how that connection works, and share the simple, everyday things I suggest to look after both ends of it.
Do my gut and brain really talk to each other?
They do, all day and all night, and in both directions. You may hear this called the gut-brain axis. I prefer to think of it as a conversation along a busy telephone line.
There are three main ways the messages travel.
Through nerves. Your gut is lined with a huge network of nerve cells, so many that it’s sometimes called your “second brain”. It can run a lot of digestion all by itself. And it’s connected to your brain by a long nerve that wanders down from the base of your skull, past your heart and lungs, all the way to your belly. It’s called the vagus nerve, and most of the messages along it actually travel upwards, from the gut to the brain.
Through hormones and chemical messengers. Your gut makes many messengers that tell your brain whether you’re hungry or full, and that play a part in how settled you feel.
Through your gut bacteria. Living in your gut is an enormous community of bacteria and other tiny organisms. I like to call it your gut garden. These bacteria help digest your food, and as they feed on the fibre you eat, they produce substances that help look after the lining of your gut and play a part in calming inflammation. That, in turn, seems to influence how you feel.
Why does stress upset my stomach?
When you feel under pressure, your body switches into alert mode, the same response that once helped us run away from danger. In alert mode, digestion is not a priority. Why would your body spend energy on lunch when it thinks it needs to run? So blood is sent away from your gut towards your muscles, the gut can speed up or slow right down, and the stomach can feel tight.
The opposite state is often called “rest and digest”. It’s when your body feels safe, and it’s the state in which digestion works best. That’s why eating in a hurry, standing up, while reading emails or after an argument so often ends in bloating or heartburn.
If the pressure goes on day after day, the alert mode can stay switched on in the background. Many people notice their digestion becomes more sensitive during stressful times, and their gut calms down on holiday. That’s the gut-brain conversation, written in your own body. If you’re not sure how much stress you’re carrying, I listed some quiet signs in Uncover hidden stress. Stress shows up in our eating too, especially on long autumn evenings, as I wrote in Comfort eating in autumn.
Can my gut affect my mood?
This is where it gets fascinating, and also where I want to be honest with you, because a lot gets said about it that goes further than we know.
What we can say is this: the messages travel upwards too. When your gut is uncomfortable, inflamed or unsettled, your brain hears about it. And many people notice that when their digestion is unhappy, their mood, energy and concentration dip as well. It goes both ways: a worried mind upsets the gut, and an upset gut can make the mind more worried.
You may have read that most of your serotonin, the “happy” messenger, is made in your gut, so a healthy gut makes you happy. It’s true that a lot of serotonin is made in the gut, but it does its work there, in digestion, and doesn’t simply travel up to your brain. So I’d rather not promise you that sauerkraut will lift your mood. What I can say is that a well-fed gut garden is one part of feeling well in yourself, alongside sleep, movement, daylight, people you love and work that means something to you. And that low mood that lasts for weeks always deserves a visit to your doctor.
What does my gut garden like to eat?
Fibre, above all, and variety.
Your gut bacteria live on the parts of plants that you can’t digest yourself. When you eat lentils, beans, oats, vegetables, fruit, nuts and seeds, the fibre travels down to your gut garden and feeds it. Different bacteria like different plants, so the more variety you eat, the more varied your garden becomes. That’s why I always talk about colour: red, orange, green, purple, white. I wrote about it in Colour your plate with nutrients.
Some plants are especially good food for your gut bacteria: leeks, onions, garlic, chicory, artichokes, asparagus, slightly green bananas, oats, lentils and beans. You may hear these called prebiotics. And then there are fermented foods, like plain yoghurt, kefir, raw sauerkraut, miso and kimchi, which bring friendly bacteria of their own. I explain the difference in The gut health trio: prebiotics, probiotics and fermented foods.
Here’s what it might look like in a real day. Breakfast: overnight oats with yoghurt, a grated apple and walnuts, or eggs with sautéed leeks on rye bread. Lunch: a big bowl of lentil and vegetable soup with a piece of goat’s cheese. A snack: a pear and a handful of nuts. Dinner: sardines with roasted squash, a green salad and a spoonful of sauerkraut on the side. Nothing exotic. Just plants, in many colours, every day.
How does the way I eat affect my gut and my brain?
When I work with someone on their digestion, I always look at how they eat as well as what they eat. Because the same bowl of soup eaten in five minutes at the desk and eaten slowly at the table is, for your gut, two different meals.
Digestion starts in your head. The smell of food cooking, the look of a plate, even thinking about lunch, all tell your gut to get ready. Then chewing does a big part of the work your stomach would otherwise have to do. And sitting down, breathing and slowing down move you into “rest and digest”.
Regular meals help too. Your gut has its own rhythm, and it likes to know when food is coming. Long gaps followed by a very big meal, or grazing all day, can leave it confused. And eating late in the evening, just before bed, often makes nights less restful and mornings less hungry.
What about probiotic supplements?
You’ll find shelves full of them, often with big promises on the box. Some people find certain probiotics helpful for particular digestive problems, but they’re very different from one another, and what helps one person may do nothing for another. I don’t recommend supplements myself. If you’re thinking about trying one, please talk to your doctor or pharmacist first, especially if you have a weakened immune system, a serious illness or take regular medicines. And please never stop or change any prescribed medicine because of something you’ve read about your gut. Talk to your doctor instead.
For most of us, food is the place to start: plants, fibre, a little fermented food, and calm meals.
What helps?
Here’s what I suggest when someone wants to look after their gut and their mood together. Start with whichever one feels easiest.
1. Feed your gut garden with plenty of plants
Add one more plant to what you already eat. A handful of lentils in the soup, a grated carrot in the salad, a spoonful of seeds on your yoghurt, herbs on everything. Try to eat a few different colours every day. If your gut is sensitive, go slowly and drink well, so your gut has time to get used to more fibre.
2. Add a little fermented food
A spoonful or two a day is a lovely way to start: plain yoghurt or kefir at breakfast, a little raw sauerkraut with lunch, some miso stirred into soup once it’s off the heat. If you bloat easily, start small. I share how to choose fermented foods that really are alive, and my easy homemade sauerkraut, in Fermented foods for beginners.
3. Breathe before you eat
Before you pick up your fork, stop. Put your hand on your belly and take three slow breaths, letting the out-breath be a little longer than the in-breath. That longer out-breath gently invites your body out of alert mode and into rest and digest. It takes less than a minute, and you can do it anywhere. I shared more simple practices in Breathe your way to mindfulness.
4. Sit down, slow down, chew
Eat at the table, not in front of a screen, and put your fork down between mouthfuls now and then. Chew until your food is soft. It sounds almost too simple, but many people find this alone makes a real difference to bloating and heartburn.
5. Look after your nervous system every day
Your gut feels everything your mind goes through. So the kindest thing you can do for your digestion is often nothing to do with food at all: a walk outside, time with people you love, enough sleep, a few minutes of quiet. Autogenic training, which I teach, is a gentle relaxation method that helps your body switch off alert mode by itself; one of its exercises even focuses on warmth in the belly. It’s best learned with a qualified teacher, and I explain it in Autogenic training: more than just a relaxation technique.
What doesn’t help?
Cutting out whole food groups on your own. Removing lots of foods without guidance can leave your gut garden with less to eat.
Eating in a rush, standing up or on the move. Your body can’t digest well while it thinks it’s in a hurry.
Adding a lot of fibre overnight. Go gently, or your gut will complain.
Expecting a pill to do it all. No supplement replaces plants, sleep and calm.
Try this for one week
For seven days, at one meal each day, do three things: sit down at the table, take three slow breaths before you start, and add one plant you haven’t eaten yet that week.
Each evening, write down two words in a little notebook: how your belly felt, and how your mood was.
At the end of the week, read your notes. Many people notice their digestion is calmer on the days they ate slowly, and that their mood and their belly often moved together. That’s the conversation between your gut and your brain, and now you’re listening to it.
Frequently asked questions
What is the gut-brain connection in simple words?
It’s the constant two-way conversation between your digestive system and your brain, through nerves, chemical messengers and your gut bacteria. It’s why stress can upset your stomach, and why an unhappy gut can affect how you feel.
Can stress cause bloating and digestive problems?
It can play a big part. When you’re stressed, your body puts digestion on hold, so slowing down, breathing and eating calmly often help as much as changing what you eat.
What foods are good for the gut-brain connection?
A wide variety of plants: vegetables, fruit, lentils, beans, oats, nuts, seeds and herbs, plus a little fermented food such as plain yoghurt, kefir or raw sauerkraut. Variety and regular meals matter more than any single food.
When should I talk to my doctor?
Please see your doctor if your bowel habits change and stay changed, if you notice blood, lose weight without trying, have ongoing pain, or feel low or anxious for weeks. Talk to your doctor or pharmacist before taking any probiotic or other supplement, and never change prescribed medicine without their advice.
Would you like some help?
Looking after your gut is rarely only about food. It’s about how you eat, how you sleep and how much you carry, and that’s exactly how I work. I run group programmes in nutrition and health, such as Six Tuesdays in Montignac, where digestion, stress and everyday eating sit side by side. If you’d like to hear when the next group opens, simply write to me at hello@catherinepolet.coach.
You can also work with me one to one, online, wherever you live. Book a free 20-minute call and tell me what your belly has been telling you. We’ll find a gentle place to start.
About Catherine
I’m Catherine Polet, a holistic nutrition health coach, yoga and autogenic training teacher for more than 30 years, author and speaker. I help people find a way of eating and living that suits their own body, online in English, French, Spanish and German, and in person in Southwest France.
