THE GUT BRAIN CONNECTION
“I’ve got a gut feeling about this”. We have all used this expression at some stage of our lives. There is a real relevance to this as our gut really does influence our feelings!
One way this happens is through the vagus nerve. This nerve joins your brain to your intestines, and along the way connects other organs also, such as the heart. It is one of the largest nerve systems in our body, second to the spinal cord. The vagus nerve influences our parasympathetic nervous system, which is the ‘rest and digest’ part of our nervous system.
This ‘enteric nervous system’ of the intestines is known as the second brain
Stress, fatigue and anxiety reduces vagal nerve activity. When there is poor vagal nerve activity this manifests as low digestive enzymes secretion and therefore poor digestion of foods and poor gallbladder function. This poor gut function then leads to overall inflammation in the body and this inflammation inhibits vagal activity. It’s a vicious cycle! It can lead to IBS symptoms (irritable bowel syndrome) with symptoms such as erratic bowel movements, bloating, flatulence and intestinal cramps.
Poor vagal activity → Decreased gut, pancreatic and gallbladder function
Mental health disorder → POOR BRAIN FUNCTION decreased gut immune system & intestinal blood flow
Leaky blood brain barrier ← pathogenic gut bacteria
and activation of microglial cells leaky gut, low grade inflammation
*Microglial cells are immune cells which can cause inflammation of the brain.
Leaky gut …. Leaky brain
Leaky gut or intestinal permeability is when your small intestine becomes more permeable and unwanted molecules are absorbed back into the blood stream instead of being excreted.his is a leaky gut barrier.
This is more prevalent today and I see it regularly in my clinic.
Leaky gut can be caused by;
- food allergies or intolerances
- intestinal dysbiosis (imbalance of bacteria in bowels)
- pathogens such parasites, bacteria or candida
- from frequent antibiotic use
- ongoing severe stress
- poor dietary choices.
- Poor digestion and/or low stomach acid
- Excessive alcohol intake
- Frequent NSAIDS, antacids or aspirin use
Leaky gut leads to inflammation which can increase production of cortisol (from the adrenal glands) and reduces the function of the inhibitory neurotransmitters such as GABA, which makes us feel calmer. Therefore leaky gut can lead to anxiety. It can also result in poor sleep, reduced production of serotonin and melatonin (our sleep hormone) and chronic pain.
The inflamed brain, anxiety, fatigue and poor memory
Leaky gut can cause symptoms such as fatigue and anxiety and even depression.
These symptoms occur when the leaky gut causes inflammation in the body, and this inflammation can access the brain (the blood brain barrier) and lead to negative brain and mood health. If this is ongoing it reduces brain cell function. If it happens in the hippocampus of the brain, this contributes to low mood and cognitive function, therefore memory is affected.
“Inflammatory, toxic and oxidative stressors that arise from leaky gut can deteriorate blood brain barrier integrity. This allows the passage of unwanted compounds into the central nervous system, setting off a cascade of damaging reactions”. (1)
An example of this is the high levels of ‘MMP -9’s’ in people with schizophrenia and depression. MMP-9 is ‘matrix metalloproteinase -9’ which is a specific proteolytic enzyme which breaks down the ‘extracellular matrix’ (the complex meshwork which fills the space between the cells of your body’s tissues).
Leaky gut breaks down tryptophan, which is an amino acid needed for the production of serotonin (our happy hormone) and melatonin (our sleep hormone). You produce neurotransmitters such as serotonin and dopamine in your gut. It also activates our HPA axis, which is the communication of the hypothalamus, pituitary (glands of the brain) and the adrenals. Which can over activate the production of cortisol and adrenalin, leading to anxiety.
Over exercising is a form of inflammation which can contribute to leaky gut. So if you have a leaky gut then reduce your exercise to light to moderate.
When homocysteine levels are high, as mentioned in my previous blog on MTHFR, this results in inflammation and MMP-9 and increases intestinal permeability (yes, the leaky gut again!). This high homocysteine can be linked to having the MTHFR gene mutation.
What to do
Treat leaky gut with change of diet and lifestyle, antimicrobials, pre and probiotics and gut healing supplements. As treating leaky gut is quite complex and individualised to each person, consulting a naturopath is the best course of action here. Anti inflammatory herbs such as curcumin (in turmeric) and fish oils can be taken.
Reduce stress, anxiety and reduce exercise if there is too much.
Stimulate the vagus nerve. You can do this by singing loudly, gagging (even though not fun), gargling several times a day, with coffee enemas (not for everyone) and yoga. You could try the following exercise;
Yoga poses for digestion and vagus nerve stimulation
Kneel on a yoga mat with your buttocks on your heels. Put a rolled blanket on your lap and let it rest against your lower abdomen. Inhale to lengthen your spine and then exhale and lean forward over the blanket. Try to reach forward far enough so that you ribs are over the top of the blanket. Slowly walk your fingers forwards reaching your head down towards the mat. Breathe fully and stay in the pose as long as you like. To exit the pose just walk your hands back into a seated position.
Also deep breathing, in for three and out for five, shuts off the sympathetic nervous system ( the ‘flight and fright’) and allows for vagal activation (which activates the parasympathetic nervous system to do with – resting and digesting!)
If you have a leaky gut then adhering to an anti inflammatory gluten and dairy free diet for at least 6 weeks is recommended. I also suggest the avoidance of all sugars and processed foods. Anti inflammatory diet would contain oily fish, nuts and seeds, organic eggs, lots of organic vegetables, some fruit and limited gluten free grains such as organic brown rice, buckwheat and quinoa (they are really seeds).
Gluten has been shown to harm the gastrointestinal tract, brain and nervous system. A third of people with gluten sensitivity show no symptoms. Wheat is especially highly processed now days and it is harder to digest.
Eliminate known allergens and food sensitivities or test for these. You can also try an elimination diet and slowly introduce one food at a time to observe reactions.
Mood and gut health, to sum up…
Having and maintaining a good bacterial balance in the gut will improve;
- Digestion and nutrient uptake
- The immune system
- neurotransmitter production (ie serotonin)
- protection against toxic agents and heavy metal toxicity that can reduce mental and cognitive health
- prevention leaky gut
- prevention of local infections which can cause mood imbalances
As it is a two way street, anxiety and stress can cause leaky gut and leaky gut can cause anxiety and low mood. Re-establishing the microflora (the good bacteria) in the intestines plays an the important role of maintaining healthy moods in the long term.
If you suspect you have a leaky gut or are experiencing any of the above mentioned symptoms, please contact me for a consultation.
Biological mood management and mental health. Stacey Jarvis.
Dr. Sircus “The function of the vagus nerve”
(1) FX Medicine spring 2014. ‘The state of mind – How gut health affects the brain’. Bioceuticals trade manual
The digestive and renal systems ; Henry Oseiki and Fiona Meeke