Do you know that intestinal microbiota plays an important role in mental health?

Alterations in the microbiota are common in patients with depression. Taking good care of your gut health can help support those who struggle with their mental health, along with appropriate treatment tailored for the individual.

Gut dysbiosis (an imbalance in gut microbiome) has been linked to several mental illnesses. Those with various conditions such as depression, bipolar disorder, schizophrenia, and autism have been found to have significant alterations in the composition of their gut microorganisms.

Thus, this imbalance can be improved through a balanced diet that can support the mental health of the person and can work to make their psychological treatment more effective.

It should be noted that depression is a systemic disease, in which different systems of the organism come together. If a poor diet or other inappropriate habits cause intestinal dysbiosis, the gut-brain axis is altered and complicates the evolution of depressive disorder.

Therefore, this microbiota imbalance must be explored to support better recovery from depression.

Diet as a management tool

Experts agree that poor diet & quality sleep, a sedentary lifestyle, pollution and not being in contact with nature and isolation (as has been happening since the appearance of covid 19), are some of the factors that affect our microbiota and our mental health.

We know that 95% of serotonin (known as the happiness hormone) is manufactured in the intestine and travels to the central nervous system through platelets, crossing the blood-brain barrier. We also know that no less than 100 billion bacteria of some 1000 different species live in our digestive tract, especially in the colon.

Functional Foods

For years, the potential to modulate the microbiome-gut-brain axis and, consequently, mental health, through functional foods, has been a topic of great interest. Functional foods are broadly defined as foods that supply additional psychological benefit, more than just nutrition. Some of the foods considered functional are fermented and it is because their fermentation process gives rise to functional microorganisms (probiotics), which improve the proliferation of beneficial bacteria in the intestine and bioactive components that have the ability to modify the intestinal microbiota and consequently influence the immune, endocrine and nervous systems.

Foods to include more in the diet, to support mental health:

  • Foods high in tryptophan: An amino acid, essential for producing serotonin. Sources include milk, turkey, chicken, fish, oats, chocolate, tofu, nuts & seeds.
  • Sources of omega-3. It is estimated that 1 third of the fatty acids in the grey matter of the brain are made up of omega 3 and according to studies it can reduce the symptoms of depression by at least 10%: Oily fish such as salmon and mackerel, as well as vegan sources such as walnuts & seeds.
  • Foods high in folic acid. Folic acid deficiency is more common in those that suffer from depression.Good sources include whole grains, peanuts, or green leafy vegetables such as spinach or Swiss chard.
  • Rich sources of magnesium. A mineral whose deficiency is associated with states of stress, memory problems, attention and fatigue. Great sources are whole grains, nuts & seeds, soy products and dark chocolate.

We recommend prioritising whole grains and a range of vegetables and fruits, rich in vitamins and minerals, which help supply glucose to the brain and are rich in B vitamins and zinc, very important for our mental health.


People who regularly eat fast food are 51% more likely to develop depression than those who don’t eat fast food often. And although various factors interact, it has been proven that consuming a diet rich in saturated fats, added sugars, higher volumes of meat, and low in vitamins, minerals, and antioxidants leads to a decrease in our mood and the possibility of developing depression.

These foods should be consumed less often, as well as considering the intake of alcohol, which can increase feelings of anxiety and depression for many. Research has shown that aspartame (an artificial sweetener) slows down the production of serotonin and dopamine.

For a personalised approach to your diet and link with mental health, reach out to one of our registered dietitians today!


Written by Nadia, dietetic student intern.

Reviewed by Reema Patel, Registered Dietitian


1 – Jacka, F. N. et al (2017) A randomized controlled trial of dietary improvement for adults with major depression (the “SMILES” trial). BMC Medicine. 15:23.

2 – Rogers, G. B. et al (2016) From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways. Molecular psychiatry. 21(6): 738-748.

3 – Sherwin, E. et al (2016) May the force be with you: the light and dark side of the microbiota-gut-brain axis in neuropsychiatry. CNS drugs. 30(11): 1019-1041.