Introduction:

Nutritional Psychiatry

The field of ‘Nutritional Psychiatry’ is a relatively nascent field in which various research is still going on. Our brain is continuously working even while we are sleeping. It not only takes care of our physical functioning like heartbeat, breathing, swallowing, ambulation, etc., but also takes care of our thoughts and emotions, and our perception of the world around us which is a continuous process.

For this hard work, we need to fuel our brains with food. The food we eat and the quality of that food make a significant difference in our brains’ functioning.

For example, diets rich in simple sugars will harm the brain by worsening our body’s insulin regulation, increasing inflammation and causing oxidative damage to cells. Eating nutrient-rich foods/complex sugars protects our brain from such oxidative damage to cells and neurons.

The Gut-Brain Axis

It is a two-way path that connects the gut and brain. This pathway is not only anatomical, but it also includes hormonal, metabolic, and immune routes.

The hypothalamic-pituitary-adrenal (HPA) axis, autonomic nervous system (ANS), and nerves within the gastrointestinal tract, all connect our gut to the brain, allowing the brain to influence our gut activities, and allowing the gut to influence our brain, especially mental health.

Nutritional Psychiatry

To understand this influence on mental health, let’s see this example. Several neurotic disorders like anxiety, depression, and autism spectrum disorders have a well-established connection to functional gastrointestinal problems.

On the other hand, gastrointestinal problems, like irritable bowel syndrome, often present with psychological comorbidities, mostly anxiety disorder.

In this article, we will be discussing the metabolic pathway of our gut–brain axis in detail.

Metabolic Pathway of Gut-Brain Axis:

Bacterial metabolites (particularly short-chain fatty acids or SCFA) derived from the bacterial fermentation of sugar, starch, etc., play a key role in this pathway. They act like local hormones, stimulate the sympathetic nervous system and influence our immunity. Not only that, microbiota-derived SCFAs can traverse the blood-brain barrier and control microglia homeostasis which in turn can cause brain tissue homeostasis and changes in behaviour.

There are studies which say that the disturbances in the metabolism of short-chain fatty acids are connected to the onset of autism through the disturbances in microglial homeostasis.

These short-chain fatty acids also control the manufacture of serotonin which is derived from the gut and activates afferent nerve endings which are linked to the central nervous system. We all are aware of the importance of serotonin in regulating our mood.

Another metabolite derived from gut microbiota is lipopolysaccharide (LPS). Research has proven that when LPS passes into the blood, antibodies are generated by the body to act against the LPS and the levels of these antibodies are more in people who suffer from depression.

 

Conclusion:

Research is now focusing on single foods, or nutrients available in the foods, instead of single nutrients. What we eat in excess is more important in causing medical problems rather than what we do not eat enough of.

The Thiru Kural rightly says,

English Couplet 945:

With self-denial take the well-selected meal;
So shall thy frame no sudden sickness feel.

Couplet Explanation:

There will be no disaster to one’s life if one eats with moderation, food that is not disagreeable.

Dr. Kurinji G R

Dr. Kurinji G R
Consultant – Behavioral Science,
Kauvery Hospital, Chennai

Kauvery Hospital