Your mood health is dependent on many factors which includes family history of mental health issues, genetic make-up, diet and lifestyle factors. Neurotransmitter production and function is key to mood health.


Neurotransmitters such as serotonin, dopamine, adrenaline, and GABA are chemical messengers which pass information through the brain and nervous system. Many neurotransmitters are shared by the digestive and nervous system alike. Neurotransmitters influence and regulate heart/breathing rate, appetite, energy levels, gut function, mental performance, pain levels, mood and sleep. Poor neurotransmitter function is linked to fatigue, anxiety and mood disorders.

Signs and symptoms linked to neurotransmitter and hormone dysfunction are depression, anxiety, compulsive behaviour, addictions, ADD and ADHD, adrenal dysfunction, insomnia, mental fog, cravings, loss of appetite control, fatigue and low libido.


One important and commonly known neurotransmitter is serotonin. Serotonin is responsible for regulating mood health, sleep, appetite, aggression, digestive processes and pain control. It is estimated that 80% of serotonin is produced in the gut. Serotonin production may be decreased due to poor gut health, stress, fluctuating hormones, poor diet, use of stimulant medications or caffeine and genetic predisposition. Low serotonin levels may cause low mood, anxiety, worry, depression, obsessive thoughts and behaviours, carbohydrate cravings, PMS, sleep cycle disturbances, constipation and reduced pain threshold. Serotonin production is reliant on intake of an amino acid (a building block in proteins) called tryptophan which is available from eggs, meat, fish and other protein sources combined with a small carbohydrate snack, nutrients listed in figure 2 and is boosted by regular exercise, adequate sleep, and healthy gut function.

Five other important neurotransmitters, their functions and possible links to symptoms are listed below:

  1. GABA is a major inhibitory neurotransmitter found in the nervous system and balances excitatory neurotransmitters. High GABA levels may indicate high excitatory neurotransmitter levels and acts to balance their effect. High GABA levels produce a calming effect but may also cause lethargy, feelings of sedation, and foggy thinking. Low GABA levels are linked to poor functioning of the adrenal glands. Without the inhibiting function of GABA, impulsive behaviours are often poorly controlled, contributing to a range of anxious and/or reactive symptoms that extend from obsessive compulsive behaviour to epilepsy. Alcohol and benzodiazepine drugs (tranquilisers e.g. Valium) act on GABA receptors and imitate the effects of GABA.
  2. DOPAMINE is principally responsible for controlling the pleasure/reward pathway, learning, memory, sleep/wake cycle and motor control (or coordination of movement). Its function creates both inhibitory and excitatory action depending on the receptor it binds to. Memory issues are common with both high and low dopamine levels. Caffeine and medications for ADD/ADHD often improve focus by increasing dopamine release, although chronic stimulation of this release can reduce dopamine over time.
    Low dopamine levels are linked to loss of motor control, depression, cravings, compulsions, loss of satisfaction and addictive behaviours (drug and alcohol use, smoking cigarettes, gambling, and overeating). Addictive behaviours may be an unconscious attempt to self-medicate, looking for the satisfaction that is not occurring naturally in the body.
    High dopamine levels may be related to hyperactivity, anxiety, schizophrenia, autism, mood swings, psychosis and attention disorders.
  3. NORADRENALINE is an excitatory neurotransmitter produced in the central nervous system and also in the adrenal glands. Norepinephrine is involved heightening attention/focus, regulating heart rate, influencing blood flow, and suppressing inflammation. It helps prepare the body for a stress response. High levels of noradrenaline are often linked to anxiety, stress, high blood pressure, and hyperactivity, whereas low levels are associated with lack of energy, focus, and motivation.
  4. ADRENALINE is an excitatory neurotransmitter made from noradrenaline in the central nervous system and the adrenal glands. Adrenaline helps regulate muscle contraction, heart rate, glycogen (sugars in the muscles) breakdown, blood pressure and more, and is powerfully involved in a stress response. High levels of adrenaline are linked to hyperactivity, ADHD, anxiety, excessive sweating, palpitations, insomnia, and poor adrenal function. Chronic stress can reduce adrenaline supplies which are associated with difficulty concentrating, lethargy, depression, insufficient cortisol (stress hormone) production, chronic stress, poor recovery from illness, dizziness and more.
  5. GLUTAMATE is an excitatory neurotransmitter and is thought to be the most abundant and active neurotransmitter in the nervous system and metabolism. Glutamate is involved in normal brain function including thought, memory and learning. High levels of glutamate may cause excitotoxicity and nerve cell damage, and is linked to panic attacks, anxiety, difficulty concentrating, OCD, Alzheimer’s disease, and autism. Low glutamate levels may cause agitation, memory loss, sleeplessness, low energy levels and depression.


Note: Levels of Serotonin, GABA, Dopamine, Adrenaline, Noradrenaline and Glutamate  may all be tested via a simple urine test.

Gut Health and Mood

Increased gut permeability may allow protein particles (casein’s from dairy products and gluten from wheat, barley,oats and rye) which contain ‘morphine’ like substances to pass into the blood stream and attach to brain receptors. These substances have an uplifting effect, and then unpleasant withdrawal symptoms e.g. anxiety, low mood, headaches food cravings and brain inflammation.

Beneficial bacteria in the gut produce B vitamins which aids in the production of neurotransmitters. Pathogenic bacteria produce toxic substances that may pass into the brain and cause inflammation, brain fog, anxiety and depression and is linked to attention deficit disorder, attention deficit and hyperactivity disorder, autism and mental health disorders. Pathogenic bacteria may also cause local inflammation in the gut which is linked to irritable bowel syndrome (IBS), inflammatory bowel disease, diverticular disease, Crohn’s disease and ulcerative colitis.

As a qualified gut and psychology syndrome practitioner I find laboratory stool testing valuable in the assessment of gut inflammation, digestion and the composition of the gut bacteria; and helps to determine a gut healing protocol which often involves removing gut pathogens with herbal antibiotics, removing food substances that may be irritating the gut lining, possible supplementation of digestive enzymes (to aid digestion of foods) and probiotics (beneficial strains of gut bacteria)/probiotic foods.

Brain and neurotransmitter production/function relies on adequate intake of: