You are what you eat

The role of our diet in taking care of our physical health is well-known. Whether our goal is to lose weight or to avoid the development of long-term heart disease, there is plenty of information and guidelines out to help us choose the right diet for our goal. In recent years, however, research has shown more and more evidence that our diet has a significant impact also on our mental health and links have been found between our diet and the development of depression, schizophrenia, dementia, and ADHD.

Have you ever had a “gut feeling” or “butterflies in your stomach”? In our gut, which has been called our second brain, we have over 100 million neurons, which make up the Enteric Nervous System.¹ Although this second brain doesn’t process or create thoughts, it has a constant bidirectional communication going on with the brain via the Vagus nerve^2,3,4 and thereby it affects our mood, thoughts and feelings significantly. This is why severe emotional stress can make us feel nauseous, lose our appetite, or affect our bowel movements. Our gut is also the centre for our immune system and produces over 90% of our serotonin.^1,5 Serotonin, as we may have heard, regulates our mood, digestion, and sleep, thereby playing an important role in our mental health.^3,6

Within the gut we have the microbiota which consists of trillions of microorganisms – bacteria, fungi, viruses, and cells³- spread out on the walls of our gastrointestinal (GI) tract.^5,7 The microbiota is responsible for nutrient breakdown, allowing us to get the full benefits from the foods we eat.⁴ For instance, fermentation by the microbiota produces short-chain fatty acids which are vital for our immune system.⁸ For this process to work properly, diversity in the microbiota is key.³ Having a varied diet which gives us all the necessary proteins, carbohydrates, vitamins, minerals, and fats, keeps our microbiota diverse and able to process all types of foods properly.³

As already mentioned, the centre of our immune system is in our gut. Our immune system has a defence mechanism in place for dealing with injuries and internal or external stress – inflammation.⁹ The foods we consume can have pro- or anti-inflammatory properties.¹⁰ Pro-inflammatory foods include red meat, processed meals, sugary drinks, refined carbohydrates (for instance white bread, desserts)¹⁰, trans fats, and alcohol.¹¹ Anti-inflammatory foods include fatty fish, berries, green leafy vegetables, beans, nuts, legumes, and seeds.^12,13 Pro- and anti-inflammatory diets have been suggested to play a role in the control of auto-immune diseases of the Central Nervous System, such as Multiple Sclerosis,^3,7,8 affect the risk of cardiovascular disease,^10,13 and have a causal effect in the development of psychiatric disorders.^3,9,13,14 It is the microbiota that is responsible for the immunologic, neuronal, and endocrine changes which, when consuming high amounts of inflammatory foods, can lead to obesity and mental health disorders.^7,15 Some studies have found that supplemental probiotics can restore gut microbiota and prevent inflammation¹⁶, thereby decreasing depressive symptoms and increasing cognitive function in humans.¹⁵

Although radically changing our entire diet to minimise the consumption of inflammatory foods might seem an unachievable task, there are several things we can do today to get the full benefits of food consumption to our mental health. Firstly, we can ensure we eat meals regularly throughout the day. Our brain is always switched on and needs fuel to function.¹ Skipping meals will result in a drop in our blood sugar, which can make us feel tired, weak, irritable, unable to concentrate, and depressed.^1,17 Secondly, we can take care of our microbiota by eating balanced meals, ensuring we get enough proteins, healthy fats, vitamins, and carbohydrates for the optimal function of our body and brain.^1,17,18 Depression has been linked with a deficiency in vitamins, minerals, amino acids, and fatty acids.¹⁸ Thirdly, apart from our diet, the microbiota is also affected by our sleep and exercise routine.^3,8 Keeping to a consistent circadian rhythm and exercising regularly have a significant effect on our physical and mental health.

As we have learned, our diet does not only affect our physical health, but also the functioning of our brain and mental health. Let’s all take good care of our microbiota by eating fresh fruits and vegetables, fatty fish, beans, legumes, nuts, seeds, and other anti-inflammatory foods. This will help us be happier and healthier. Remember, we are what we eat.

See also:

• https://www.mind.org.uk/information-support/tips-for-everyday-living/food-and-mood/about-food-and-mood/
• https://www.youtube.com/watch?v=VVaOe6RYZts
• https://www.mentalhealth.org.uk/sites/default/files/food-for-thought-mental-health-nutrition-briefing-march-2017.pdf