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Neuroinflammation: The Cause of Brain Fog

Life is challenging enough without your brain being mired in a thick, hazy fog. If you can’t seem to think clearly or focus on specific tasks, if you are constantly forgetting why you walked into the bedroom or why you picked up your phone, or if you often have a word just on the tip of your tongue but can’t seem to recall it, it’s likely you are suffering from brain fog.

Brain fog is not a diagnosis or medical condition, but instead a symptom of a deeper issue going on in your body, particularly the gut. Although brain fog is a common symptom in many more serious medical conditions like hypothyroidism, Crohn’s disease and fibromyalgia, these conditions often also are associated with imbalances in the gut, suggesting that the lack of mental clarity, slipping memory, poor focus and that feeling of your brain just not getting up to speed are really the result of poor gut health.

What the Research Says About Brain Fog

Several recent studies have confirmed what functional medicine practitioners have suspected for some time: that brain fog is the result of inflammation in the brain[1], or neuroinflammation.

In one study, 20 healthy volunteers were subjected to cognitive tests before and after receiving a vaccine that induced short-term brain inflammation. The results showed that the subjects required more cognitive effort when they were experiencing inflammation[2].

Neuroinflammation arises when toxic substances cross the blood-brain barrier, activating the brain’s immune system. While inflammation is a perfectly natural (and crucial!) response by the immune system to fight off toxins, viruses and pathogens, long-term inflammation is what wreaks havoc in the body.

There are a number of underlying causes for this. Let’s dig deeper.

Gut Dysfunction

The gut and the brain are inextricably linked through physical and chemical connections involving the vagus nerve, neurotransmitters and the gut microbiome.

In the walls of your digestive lining are two thin layers of over 100 million neurons, also known as the enteric nervous system (ENS). The ENS starts from the oesophagus to the rectum, and cleverly communicates with the brain and spinal cord[3]. Additionally, the gut and brain also engage in “crosstalk” through our hormones and immune system.

This bidirectional link between the central nervous system of the brain and the enteric nervous system of the gut is known as the gut-brain axis, and explains how what’s happening in the gut affects what happens in the brain, and vice versa.

In a condition called Leaky Gut Syndrome (or Gut Permeability), the gut becomes dysregulated by a variety of factors such as an unhealthy diet, food intolerances, overuse of medication and chronic stress. The tight connections between the cells of the intestinal lining become weak or damaged, making the lining more permeable than it should be.

Image from: TCI Medicine 

When this happens, food particles, bacteria and other toxins are able to leak through the now-permeable intestinal lining and into the bloodstream where they don’t belong, triggering inflammatory responses in different parts of the body – including the brain. The blood-brain barrier can then become disrupted, exposing the brain to toxins and cause neuroinflammation.

And what does that mean? That means the start of your brain fog! Do you see how it’s all linked?

How to Combat This

Heal your gut

If you suspect you have a gut imbalance or a more serious condition like leaky gut syndrome, you should first consult your naturopath or functional medicine doctor first to get a test done. But in the meantime, you can still start healing your gut at home with foods like bone broth and probiotic-rich foods.

Bone broth contains collagen, which nourishes and repairs the intestinal lining and can calm an inflamed gut. We recommend homemade bone broth from organic bones instead of store-bought – just so you know exactly what you’re putting into your body.

Probiotic-rich foods include fermented foods like kimchi, sauerkraut and tempeh to provide your gut with good bacteria and help restore balance to the gut microbiome.

Reduce inflammation

Since brain fog is the symptom of inflammation in the brain, reducing overall inflammation is key to getting to the root of the problem. Add turmeric into your daily meals (add it to a curry or in your winter soups) or take a high quality curcumin supplement, which is the chemical in turmeric that reduces inflammation[4].  

It is also a good idea to review your diet, cutting out as much inflammatory foods as possible. Gluten, dairy, sugar and processed foods are some examples of foods that cause inflammation. 

Oxidative stress

Oxidative stress occurs when there is an excess of free radicals relative to antioxidants in your body, which can cause cell and tissue damage and chronic diseases.

This can happen as a result of anything that causes long-term and persistent stress such as psychological stressors, sleep deprivation, poor diet and other unhealthy lifestyle habits.

Because the brain uses a significant amount of oxygen, it is particularly susceptible to oxidative stress. When this happens, structures inside the brain cells can become altered or damaged and in some cases, cell death can occur, leading not just to brain fog, but to more serious conditions like Parkinson’s and Alzheimer’s disease.  

How to Combat This

Broccoli sprouts

Hundreds of scientific publications suggest that broccoli sprouts have the highest antioxidant effect in human cells. Broccoli sprouts contain a compound called glucoraphanin, which is converted into sulforaphane when ingested, which help protect our cells, tissue and DNA from free radical damage.

While you can the sprouts to your salads, you’ll need to eat a lot of it to get the therapeutic dose – so look for a supplement that contains a high quality broccoli sprout concentrate.

Antioxidant-rich foods

Eat more foods rich in antioxidants – green tea, brightly coloured fruits and vegetables, lots of herbs and spices. 

Prioritise sleep

An obvious one! If you’re not getting adequate sleep, If you’re not sleeping well at night, your body and brain don’t have time to repair themselves. Studies have shown that the lack of sleep decreases glutathione, the antioxidant that prevents inflammation and oxidative stress in the brain[5]. 

Food and Histamine Sensitivities

Food sensitivities such as gluten or dairy sensitivity (or intolerances) can also trigger brain fog by first activating an immune response in the gut, which then spreads to the brain through the gut-brain axis.

Histamine sensitivities occur in people who don’t break down the immune cell histamine properly. This causes a free radical called superoxides to be released, triggering an inflammatory response.  

How to Combat This

Try an elimination diet

An elimination diet involves removing a specific food group for a set period of time, then gradually reintroducing them to determine what is triggering adverse reactions.

Whether it is a gluten elimination diet or a histamine elimination diet, this should always be done under the supervision of a natural healthcare practitioner.

Chronic Stress

Chronic stress diverts energy towards the stressor and away from your brain and other crucial bodily functions. With decreased blood flow and energy in your brain, mental clarity and focus can be impaired. 

Studies have also shown that prolonged levels of cortisol results in the shrinkage of the hippocampus[6], which is the part of the brain responsible for learning and memory, as well as accelerated brain ageing[7] with its neurodegenerative effect. 

How to Combat This 

Adaptogenic herbs

Adaptogens are a class of plants and herbs that help the body adapt to stress, bringing the body back to a state of homeostasis. While there are many adaptogens, each working a little differently in the body, Holy Basil (Tulsi) and Bacopa (Brahmi) are our favourites specifically for brain fog.

Other adaptogens that help with chronic stress are Ashwagandha, Rhodiola and Siberian ginseng.


Manage your stress

Daily meditation, breath work and practices like yoga and tai chi are relaxation techniques that activate a state of restfulness in the body, counterbalancing the fight-or-flight response. Exercise is also a great way to combat stress as it reduces the body’s stress hormones such as adrenaline and cortisol, while releasing endorphins which trigger a positive feeling in the body.



[1] Theoharides, T.C. (2015). Brain ‘fog,’ inflammation and obesity: key aspects of neuropsychiatric disorders improved by luteolin. Frontiers in Neuroscience, [online] 9. doi:10.3389/fnins.2015.00225.

[2] Balter, L.JT., Bosch, J.A., Aldred, S., Drayson, M.T., Veldhuijzen van Zanten, J.JCS., Higgs, S., Raymond, J.E. and Mazaheri, A. (2019). Selective effects of acute low-grade inflammation on human visual attention. NeuroImage, [online] 202, p.116098. doi:10.1016/j.neuroimage.2019.116098.‌

[3] Dodds KN, Travis L, Kyloh MA, Jones LA, Keating DJ, Spencer NJ. The gut-brain axis: Spatial relationship between spinal afferent nerves and 5-HT-containing enterochromaffin cells in mucosa of mouse colon. Am J Physiol Gastrointest Liver Physiol. 2022;322(5):G523-G533. doi:10.1152/ajpgi.00019.2022

[4] Hewlings, S. and Kalman, D. (2017). Curcumin: A Review of Its’ Effects on Human Health. Foods, [online] 6(10), p.92. doi:10.3390/foods6100092.

[5] DʼAlmeida, V., Lobo, L.L., Hipólide, D.C., de Oliveira, A.C., Nobrega, J.N. and Tufilk, S. (1998). Sleep deprivation induces brain region-specific decreases in glutathione levels. NeuroReport, 9(12), pp.2853–2856. doi:10.1097/00001756-199808240-00031.

[6] Gianaros, P.J., Jennings, J.R., Sheu, L.K., Greer, P.J., Kuller, L.H. and Matthews, K.A. (2007). Prospective reports of chronic life stress predict decreased grey matter volume in the hippocampus. NeuroImage, [online] 35(2), pp.795–803. doi:10.1016/j.neuroimage.2006.10.045.‌

[7] Ouanes, S. and Popp, J. (2019). High Cortisol and the Risk of Dementia and Alzheimer’s Disease: A Review of the Literature. Frontiers in Aging Neuroscience, 11. doi:10.3389/fnagi.2019.00043.

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