When you think about positive mental health, your first thought isn’t usually your stomach, but there’s growing reason to suggest it should be. We’ve all heard the phrase “you are what you eat”, and while we usually apply that to our physical health, there is a real phenomenon linking the brain to the gut that could connect what we consume to how we feel.
The gut-brain axis is a two-way communication between the gastrointestinal tract and the central nervous system, via the vagus nerve, that allows the brain to send signals to the gut, and vice versa. In fact, you’ve probably experienced this without realising it. If you’ve ever felt ‘butterflies’ or had a ‘gut feeling’, this is the gut-brain axis in action.
Both the brain and the gut are home to millions of neurons that tell your body how to behave, and they both produce neurotransmitters that control feelings and emotions. For example, the neurotransmitter serotonin contributes to feelings of happiness and also controls your body clock – but the majority of serotonin is produced by the trillions of bacteria that reside in our gut microbiome, not the brain.
If the gut microbiome becomes imbalanced, signals are sent to the brain that can result in someone experiencing increased stress, anxiety or depression. Research has found that the microbiome of a person with a mental health problem is different from someone without any mental health issues. It has also been found that poor gut health may contribute to the onset and progression of mental health conditions including depression and anxiety.
A balanced microbiome (i.e. one with adequate numbers and diversity of good bacteria) can help regulate mood and reduce feelings of anxiety.
Much of what influences the health of our gut is diet, but some foods are better for it than others. The best types of food are high quality, fibre-rich whole foods that been minimally processed, and we should avoid ultra-high processed foods – what we usually term ‘junk food’. Here are some suggestions of foods to focus on, and some to avoid in order to promote healthy gut bacteria:
High-fibre foods (like whole grains, nuts, seeds, fruits & vegetables)
Fermented foods (like sauerkraut, kimchi & kefir)
Yogurt with live cultures
Omega-3 fats (found in oily fish and eggs)
Polyphenol-rich foods (like coffee, green tea, cocoa and olive oil)
Highly processed foods
Refined sugars and fizzy drinks
Red meat and processed meats
Artificial food additives (like sweeteners and preservatives)
Antibiotics and some lifestyle factors such as smoking, lack of sleep and physical exercise, and stress can also negatively impact the integrity and health of our gut.
So next time you sit down to eat, think about whether your chosen food will nourish your microbiome – if you can feed your good bacteria, it might just help improve your mood too!