How our Gut Health and Mood are Connected - Food for the Brain

Mental health conditions are on the rise and the statistics speak for themselves: a record 70 million antidepressant prescriptions were handed out in 2018, and an estimated 10 million people will be in need of mental health support in the next five years. Mood can of course be dependent on external factors, but internal factors such as fluctuations in hormones, neurotransmitters and nutrient availability can also exert considerable influence. In light of this, treating the mind and body separately does not make sense. 

Our Second Brain

Far from being distant organs, the gut and brain communicate through a complex network of neural, hormonal and immune pathways and messengers, called the “gut-brain axis”. The integrity of our digestive system directly impacts the information our brain receives, and the quality of the building blocks of the brain tissue itself.  

Poor mental health may be a symptom of imbalances in the gut-brain axis. More  than 100 million nerve cells line our gastrointestinal tract, working independently of our brains. We know that the gut-brain axis is a strong communication mechanism because anxiety and mood changes are correlated with irritable bowel syndrome and functional bowel problems such as constipation, diarrhea, bloating, pain and stomach upset.

Our mood can also be impacted by poor vagal tone. The vagus nerve connects our digestive system to our brain and is the major nerve in our ‘rest and digest’ nervous system. With busy and stressful lifestyles regularly triggering our ‘fight or flight’ response, this vagus nerve may not be functioning well, which can contribute to depression and indigestion. 

Mood and Immunity

The nervous and immune systems work together, with the brain housing specialised immune cells called microglia to help fight infections and clear away damaged cells. When stress is excessive, or when the immune system sends persistent distress signals, the inflammatory response triggered by the immune system has been linked with depression.  

Much of the immune system is housed in our gut, making sense when much of our environmental risk exposure enters the body through our food. Our gut, therefore, needs to be in good shape for our immune system to be working well.  

Maintaining Balance

Our blood sugar levels also impact our mood. Our brain is an energy hungry organ, using 25% of our total energy stores and preferring glucose to carbohydrates to keep it going. If our blood glucose levels are unstable, say from a high carbohydrate diet, this can be stressful for the brain to cope with and can cause mood swings or feeling ‘hangry’.   

Blood sugar swings can also make us feel fatigued and have a detrimental impact on an important protein, BDNF (brain-derived neurotrophic factor) essential for the survival and growth of brain cells. BDNF helps our brain cells communicate and promotes the calming neurotransmitter GABA, levels of which may be low in anxiety sufferers. It also supports how our body makes energy,  and therefore if levels of BDNF are low, we are more likely to feel fatigued, listless and at risk of experiencing mental ill health. 

Top Tip

Keeping our gut healthy with a Mediterranean style diet, abundant in fibre-rich fruit and vegetables, oily Omega-3 rich fish, and wholegrains enriched with B-vitamins, translates into increased brain health, in turn improving our mood and mental health. 

With thanks to Julie Pichler at Vagus Wellbeing for this article. 

Julie is a registered Nutritional Therapist and delivers our Workplace Wellbeing programme offering educational and empowering webinars. Julie’s specialism is the gut-brain connection and how food impacts our mood and brain health.

Find out more about our webinars here and how they can support your employees’ mental wellbeing.