Could my digestive symptoms be linked to my depression?

It may not seem obvious that your digestive health is linked to your mental health, but many scientists are now calling your gut the 'second brain', and here's why.


Scientific research is showing that our gut microbiome communicate with our brain via the nervous system, the immune system, and our hormone system.

The gut microbiome does this in the following ways:

  • It produces neurotransmitters, such as serotonin. In fact, our gut produces over 90% of all the serotonin our body makes. As this is known as the 'happy hormone', and a deficiency is associated with depression, it's little wonder people who are unhappy are called 'misery guts'.
  • Our gut microbiome produces chemicals that interact with our hormone system, such as cortisol, and can help makes us more or less resilient to stress, depending on how well we look after our gut microbiome. High cortisol levels also have a knock-on effect on serotonin, by using it up to produce different chemicals in the body (this is one theory about a cause of depression).
  • Our gut bacteria also produce chemical signals which are carried from the intestinal lumen via the enteric nervous system (ENS) and vagus nerve to the central nervous system (CNS) and our brain and back.

This means that how you feel on a day to day basis, and every neurological disease such as Parkinson’s Disease, is linked to your gut microbiome. If you suffer from low mood or depression, including a plethora of other brain disorders, it could be that your gut microbiome aren’t being fed properly and are 'fed up' themselves.

As what we eat or drink can profoundly affect our digestive function, changing your diet can significantly improve your well-being and digestion. In addition, what you eat and drink can impact your gut microbiome, especially as it is known that there is a connection between your friendly gut bacteria and every disease condition.

Did you know that your gut microbiome is now being classified as an organ in its own right?

Fascinating facts about your gut bacteria

  • There are 40 trillion bacterial cells in your gut.
  • There is 150 times more DNA is your gut microbiome than the rest of your body.
  • Your gut bacteria carries out more metabolic functions than your liver.
  • Your gut microbiome weighs around three kilos – the same as your brain!

In light of the above, more and more research is pointing to the fact that your health depends directly on the health of your gut microbiome.

So, you’ll be pleased to know that there are some surprisingly easy steps you can take to check the health status of your gut microbiome and straightforward solutions to fixing your gut health. What they are will ultimately depend on your current diet, what you need to change and your health history.  Sophisticated DNA analysis can pinpoint exactly which microbes you have in your gut, and there are specific dietary and supplemental strategies that you can employ to ensure your gut bacteria flourish to maintain and/or help reserves for any health issue you may have.

However, a good start will be to make sure you are eating enough microbe-friendly food in your diet, such as vegetables, fruit, beans, legumes, nuts, and seeds.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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London SW15 & W1H
Written by Melody Mackeown, mBANT, CNHC, BSEM | Nutritional Therapist and Health Coach
London SW15 & W1H

Melody has a Masters Degree in Personalised Nutrition and specialises in helping you with problems conceiving, gut problems, autoimmune disorders, weight loss and more.

Melody treats the whole person, not just the disconnected symptoms and as a result, clients typically see significant positive improvements to their health within just 3-6 months.

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