The Gut-Brain Axis: Mental Health and the Gut Microbiome.
This is a tale of two brains.
Did you know that it’s not only your mouth and gut that are connected, your brain gets in on the action too. This is known as the gut-brain axis, and it has a significant impact on your mood and behaviour. The gut-brain axis is an information superhighway that provides a flurry of notifications from your brain to your gut and vice versa.
The Second-Brain - The Enteric Nervous System.
Most of us will have first-hand experience of the connection between the gut and the brain - when you feel nausea before giving a presentation, a stomach ache during stressful periods, or ‘butterflies’ in your tummy when falling in love. Have you ever followed your ‘gut feeling’ because you feel something inside you telling you which decision to make? Or perhaps you’ve ignored these feelings and you’ve found yourself in a situation you’d rather not be in? This isn’t just your imagination - you’re receiving signals from your ‘second brain’, which lives inside the walls of your digestive system in your microbiome.
The Second-Brain is found in your gastrointestinal tract and is composed of 2 layers, consisting of millions of nerve cells. Although the ‘Second-Brain’ doesn’t make executive decisions like the main guy, both communicate back and forth via electrical impulses through a pathway of nerves, and this pathway influences our endocrine system (including the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands), immune system and our focus for this piece, the enteric nervous system, which controls neural pathways which impact your mental health.
Mental Health & The Gut Microbiome.
Researchers in this 2017 study asserts that the microbiome’s Second-Brain has a direct effect on our actual brain. The microbiome releases neurotransmitters that speak to the brain and vice-versa. This influences our state of mind and it plays a role in mental health conditions such as anxiety and depression.
How the Gut Influences Stress & Anxiety.
The enteric nervous system can trigger big emotional shifts, and insights from the same 2017 study, show that gut issues can cause these emotional feelings. The study reveals that people with serious disorders such as obesity, anorexia, irritable bowel syndrome, autism and PTSD - disorders that are said to be influenced by emotional triggers and psychological factors - share a common physiological symptom: a hypersensitivity to gut stimuli. Any imbalance in the gut influences our brain in a perpetual feedback loop, influencing our perception of self, the world around us, and our behaviour, according to the study.
Cell Press, a monthly journal that publishes findings related to microbes, found evidence in this study that by treating inflammation and hypersensitivity in the gut, we can help to keep feelings of anxiety and depression under control. By having greater control over these feelings, we can reduce the amount of gut inflammation and subsequently increase the number of beneficial bacteria in the gut. Happy Gut = Happy Mind.
How Stress & Anxiety Influences the Gut.
When you’re feeling stressed or anxious, your body releases peptides (short chains of amino acids) known as Corticotropin-Releasing Factors (CRF). These factors result in inflammation and an increase in gut permeability and sensitivity. Chronic exposure to stress can lead to a variety of gastrointestinal diseases, such as Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD), and even food allergies, due to stress slowing down the transit time of food within the small intestine. This 2011 study by The University College Cork, asserts that this encourages overgrowth of bacteria that compromise the intestinal barrier. Bloating, diarrhoea, constipation… these are all signs of a stressed mind causing an unhappy gut.
Keeping Your Gut and Your Brain Healthy.
So the big question that we’ve been leading up to, how can you offer support to both your gut and your brain? The key is to nurture a healthy gut flora. When we encourage a diversity within the gastrointestinal tract, we can reduce hypersensitivity and normalise our levels of stress hormones. Improving the quality and health of our friendly gut bacteria benefits our mental health and overall well-being.
Interestingly, around 90% of Serotonin levels are stored in the gut, with just 5-10% stored in the brain. Serotonin is a neurotransmitter that plays a crucial role in controlling mood. The right balance of Serotonin makes us feel calm and positive, but imbalances contribute to feelings of depression and also impacts appetite, sleep, memory and social behaviour.
Serotonin-Boosting Foods to Help your Happy Hormone.
Researchers believe that fermented foods are a strong dietary option for people wishing to fight anxiety and depression. One study found that women who drank fermented milk showed altered activity in brain regions related to emotional processing compared to those who drank normal milk, reinforcing the idea that strategies to alter our microbiome can alter our mental state as well.
Fermented foods are a rich source of healthy bacteria or probiotics. While most people associate probiotics with digestive health, these healthy bacteria have far-reaching effects on the body. Fermented foods such as Sauerkraut, Kimchi, Kombucha, Cultured Vegetable Juices, Jun Tea and Kefir assist in the digestion and absorption of the all-important nutrients that we need for Serotonin production.
This Danish study asserts that foods that are high in Vitamin B6, such as cauliflower, mushrooms, spinach, garlic, fish, celery, chicken and beef are proven to play an important role in helping our bodies to produce Serotonin. Eggs are also proven to boost blood plasma levels of Tryptophan, the amino acid from which Serotonin is biochemically derived.
Our recommendation - incorporate all of the above into your daily diet and keep a food diary to monitor the effect these foods have on your mood. As always, please be sure to seek the advice of a qualified medical professional before making any changes to your diet, they’ll support you to find the best solution to meet your individual needs.
Share your Experience! Healthy Gut, Healthy Brain.
Do you find that your dietary choices have an effect on your mental health? Share your thoughts on the food and mood connection in the comments section below.