Brain fog is something many of us experience from time to time – difficulty concentrating, feeling as if our mind was cloudy or foggy, poor short term memory recall and struggling to multi task. Often this can be related to lack of sleep, excessive stress,  or consuming too much alcohol, but for some people frequent episodes of ‘brain fog’ can be disruptive to daily performance.

Brain fog has been described in the medical literature as a:

“…constellation of symptoms that include reduced cognition, inability to concentrate and multitask, as well as loss of short and long term memory. Brain “fog” characterizes patients with autism spectrum disorders (ASDs), celiac disease, chronic fatigue syndrome, fibromyalgia, mastocytosis, and postural tachycardia syndrome (POTS), as well as “minimal cognitive impairment,” an early clinical presentation of Alzheimer’s disease (AD), and other neuropsychiatric disorders.

It is important to always have these symptoms examined by a Medical Practitioner if they are persistent or severe, however often I have patients who have seen their GP and been told it may just be stress, or they should get more sleep. Often this advice has not been found to help so it’s worth looking into other factors that may be playing a role.

Our gut health is involved in almost all aspects of our physiology, and its relationship to brain fog and cognitive performance is no exception. A common line I hear from many of my patients is “when my gut is not great, my mind is not great”.

Symptoms like bloating, excessive flatulence, gut pain, and changeable stool habits, often associated with Irritable Bowel Syndrome, also correlate with mental health symptoms of brain fog, irritability, and even things like anxiety and depression.

So what are some of these Factors in the Gut and what can you do about them?

  1. INFLAMMATION: Our gut is home to billions of bacterial cells. In fact some researchers estimate bacterial cells outnumber human cells in our bodies by a factor of 5 to 1 (or even 10 to 1 in some studies!). These bacteria play a crucial role in our digestion and absorption of nutrients, but can also cause problems if the species that live in the gut are out of balance. Some of the common types of bacteria in the gut have a substance in their cell wall called Lipopolysaccharride or LPS for short. When the immune system ‘senses’ LPS in the bloodstream it triggers a strong inflammatory response. Excess inflammation in the brain disrupts the natural balance of neurotransmitters leading to disturbances in cognition, focus and mood. If you have ever had a hangover you will have noticed the direct effect of inflammation on the brain. Common bacterial families such as bacteroidetes, proteobacteria and bilophila when present in excessive amounts in the gut can cause excess inflammation due to their high levels of LPS. These bacterial types feed off excess refined sugars, fats and oils in the diet. They also tend to overgrow when stomach acid is low or when people take acid blocking medication such as proton pump inhibitors. A diet low in refined oils and sugars and high in plant fibres can reduce these organisms. Speak to one of our practitioners about how you can test for these organisms in your gut. Symptoms of inflammation in the gut can include unexplained gut pains, bloating or swelling (especially after food) and food sensitivities.
  2. HISTAMINE: Many people know the symptoms of histamine associated with hayfever – itchy nose, runny eyes and general feeling of irritability are all symptoms of histamine release. What most people do not realise is that we (a) also produce a lot of histamine in our gut, and (b) that histamine is a neurotransmitter in the brain. Many bacteria in the gut produce histamine as a by-product of their metabolism. When the balance of bacteria is disrupted in the gut we can have elevations in histamine production that can lead to symptoms of food sensitivity, unexplained gut pains and diarrhoea. Histamine in the gut can affect histamine in the brain. In excess amounts histamine in the brain can cause feelings of anxiety and even panic. In very high amounts it can also cause brain fog, difficulty concentrating and problems retaining information(1). To reduce histamines affect on the brain you can work with a practitioner to discover whether a low histamine diet may work for you, or whether probiotics and supplements that can help lower histamine may help your brain fog.
  3. MALABSORPTION: Many key vitamins and minerals are absorbed in the gut, and some are even produced by gut bacteria. A lot of these nutrients are critical for neurotransmitter production in the brain and even a mild deficiency of these can contribute towards poor concentration, low mood, problems with memory and sub-optimal brain function. Medications for heart burn such as proton pump inhibitors, NSAIDS such as aspirin and ibuprofen, excess alcohol, tannins in coffee and tea, excess calcium in dairy, food intolerances and inflammation can have significant negative effects on nutrient absorption. In fact studies of people with fructose malabsorption have shown low absorption of tryptophan, folate and zinc – all critical nutrients for mental health. People with fructose malabsorption correspondingly have higher rates of depression in part due to this nutrient malabsorption. This is but one example of common causes of malabsorption that can significantly affect brain function.


Assuming you have first had your symptoms of Brain Fog and lack of concentration assessed by a medical doctor and been told its nothing to worry about its time to dig a bit deeper! At Merge Health we pride ourselves on being willing to look beyond the standard tests and really investigate what is going on with peoples health.

Functional Testing can really help here. These tests assess the overall function and health of the body, rather than JUST looking for disease and pathology.

Tests I often utilise in patients experiencing these symptoms include Breath Tests for malabsorption and bacterial overgrowth, Stool Microbial Testing for the balance of bacteria in the gut, Microscopic Blood Analysis for signs of inflammation and malabsorption (our Medical Scientist Tanya is an expert here!) and our Oligoscan technology which assesses for the balance of minerals and toxic metals stored in the body (results obtained instantly too!).

So if symptoms of poor concentration, lack of focus, and Brain Fog have been bothering you and you really want to seek better answers, give the clinic a call today and find out which practitioner is right for you!


  1. Theoharides, T., Stewart, J., Hatziagelaki, E. & Kolaitis, G. (2015) “Brain “Fog”, inflammation and obesity. Key aspects of neuropsychiatric disorders improved by luteolin”, Front. Neurosci. V.9 2015.
  2. Rudzki & Szulc. (2018) “Immune Gate of Psychopathology – The Role of Gut Derived Immune Activation in Major Psychiatric Disorders”, Frontiers in Psychiatry, V.9.

  3. Ledochowski, Widner, Murr & Fuchs. (2001) “Decreased Serum Zinc in Fructose Malabsorbers” Clinical Chesmistry. V.47.

You might be interested in “Prac Spotlight with Marina Martic“.

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