By Dr Tim Crowe

You are what you eat. It’s a common saying, but when it comes to your mental health, what you eat can have a profound impact on your mood and how you feel. And it is the gut microbiome and the bacteria in it that have co-evolved with humans that are the key players in this.

Why gut health is important

Our gut does more than help you digest food – it can also affect your mood. New developments in a rapidly emerging field of research show that the gut has a two-way communication link with the central nervous system – and we call this the gut-brain axis.

Initial work in mice showed that changes in the gut microbiota can go on to lead to depressive-like symptoms. Supplementing the diets of the stressed mice can reverse the problems. So, what is the case in humans then?

People with depression do have a different gut microbe fingerprint compared to healthy volunteers. And intriguingly, human clinical trials involving probiotic supplementation appear to demonstrate a positive improvement in psychological symptoms related to depression, anxiety and stress.

So, what about food and mood?

The nutrients found in healthy foods appear to work together to help the brain produce the ‘feel-good’ hormone serotonin, which is associated with improved mood and feelings of relaxation. Add to this that eating foods that maintain a steady blood-sugar level helps to stabilise mood as well.

But how does your mood affect the foods you select?

It seems that people in a good mood are more likely to prefer nutritious foods that are lower in added sugar, salt, and fat, and to focus on the long-term benefits of these healthy foods. So healthy eating improves mood which goes on to promote more healthy eating and so the positive cycle goes on.

How to improve gut health

To keep your gut ecosystem thriving and having a positive influence on your brain and mood, aim to eat more foods high in different types of fiber. Fiber is nourishment for good gut bacteria, and you will find it an array of everyday foods such as most vegetables, whole grains such as barley and oats, and legumes such as beans and lentils. Then add some fermented foods to your diets such as sauerkraut, kimchi, kefir, and yogurt which contain a good supply of healthy bacteria to add to boost your gut bacterial community. Really, the simplest advice is to eat a wide variety of nutritious whole foods from all food groups, which would naturally contain different types of fiber and beneficial gut health nutrients. And from that, you can expect to reap not just the physical health benefits, but also mental health benefits.