In this video, Dr Sanil Rege discusses Faecal microbiota transplants, The Gut-brain axis, their link to psychiatric disorders, and the Role of Probiotics.

The gut-brain axis (GBA) consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centres of the brain with peripheral intestinal functions.

Gut Microbiome

Collectively, the genetic material of the microbiome is approximately 150 times greater than the human genome, which has led some scientists to label the microbiome as a ‘superorganism’ There is accumulating evidence that bacteria secrete neuroactive compounds that have psychiatric properties that can affect sleep, appetite, mood, and cognition.

Faecal microbiota transplant (FMT)

FMT is the administration of a solution of faecal matter from a donor into the intestinal tract of a recipient in order to directly change the recipient’s gut microbial composition and confer a health benefit. There is increasing evidence for the role of faecal microbiota transplantation in psychiatric disorders.

Gut Microbiome and Neurotransmitters

These neuroactive compounds can act locally on the enteric nervous system as well as act directly on the brain either by crossing the blood-brain barrier or communicating through vagal chemoreceptors. The intestinal nervous system consists of 200-600 million neurons. It has therefore been given the term ‘Second Brain’.

Vagus nerve and the Gut microbiome

These neurons are controlled predominantly by the vagus nerve and thus the vagus nerve acts as the primary connection between the brain and the proximal intestinal tract.

Lipopolysaccharides

Lipopolysaccharides (LPS) are proinflammatory endotoxin that is a component of the outer membrane of Gram-negative bacteria. LPS can trigger an inflammatory response that has been associated with anxiety, depression, cognitive deficits, and visceral pain.

Micronutrients

Gut microbiota produces water-soluble vitamins and affects the intestinal absorption of micronutrients. Dysbiosis therefore could result in a deficiency of micronutrients contributing to depression.

Leaky gut

HPa axis dysfunction can lead to a leaky gut setting up a process of neuroinflammation.

Role of Probiotics

Pre and probiotics can regulate the capacity of intestinal microbiota, prevent leaky gut and hence reduce inflammation. Evidence suggests that daily consumption of a probiotic supplement could positively improve the mood, anxiety, and cognitive symptoms present in MDD. More research is needed.