Sometimes when you’re feeling stressed and anxious it can make you feel sick to the stomach. There is a good reason for that: the stomach or gut is one of the key connections to brain and emotional health.
This connection is known as the gut–brain axis. In fact, your body has two nervous systems: the central nervous system, your brain and spinal cord; and the enteric nervous system, the intrinsic nervous system of your gastrointestinal tract. These are formed at the same time during foetal development from identical tissues connected via the vagus nerve: the 10th cranial nerve that runs from your brainstem to your abdomen. This is the primary route your gut bacteria use to transmit messages to your brain.
Just as you have neurons in your brain, you also have neurons within your gut. This includes neurons that produce neurotransmitters such as serotonin. Serotonin is responsible for feelings of wellbeing and happiness and is found in its greatest concentration in the gut, not the brain.
The ability of the gut microbiota to communicate with the brain and influence behaviour is emerging as a very exciting concept in the scientific world of health and disease.
Research has shown that the presence of Bifidobacterium longum NCC3001 normalises anxiety-like behaviour in mice. Other findings include the ability of certain probiotics to modulate antidepressant-like behaviour by reducing pro-inflammatory cytokines and increasing levels of tryptophan, both of which have been implicated in depression.
The close connection between stress-related psychiatric symptoms such as anxiety and gastrointestinal disorders like irritable bowel disease provide further proof of the gut–brain axis. The impact of poor gut health on the functioning of the brain has been scientifically linked to a range of illnesses, including ADHD, autism, chronic fatigue, OCD, Tourette syndrome and anxiety and depression.
Stress and emotional factors can override even the most perfect diet. Stress causes many changes in the gut, including alterations in gastric secretion, gut motility, mucosal permeability, viscal sensitivity and barrier function. Evidence also suggests that the hormones secreted during a stress response contribute to the overgrowth of bad bacteria.
Your gut and your emotions are a two-way street, so addressing the state of your mental health — not just the food you eat — is vital.
