Published September 21 2015
Brain fog is a type of cognitive impairment, and is common in people with thyroid and autoimmune thyroid conditions. Some of the symptoms associated with this condition include slow thinking, difficulty focusing, confusion, lack of concentration, forgetfulness, or a haziness in thought processes. In this article I’m going to discuss five of the common causes of brain fog, and then I will talk about some of the things you can do to help with this condition.
1. Low thyroid hormone levels. Having low thyroid hormone levels can lead to numerous symptoms, and brain fog is one of them. Although many are aware that normal levels of thyroid hormone are important for proper brain development, thyroid hormone also plays an important role in cognition in adults (1) (2). In addition, the activation of something called microglia cells can cause neuroinflammation (3) (4), which can lead to the symptoms of brain fog, and eventually neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. And normal T3 levels play a role in modulating microglia cells (5). In other words, healthy thyroid hormone levels are essential for healthy microglia cells. Just to be clear, I’ve also had people with hyperthyroidism and Graves’ Disease experience symptoms associated with brain fog. When this is the case it is usually due to other factors, and not the thyroid hormone imbalance.
2. Neurotransmitter imbalances. Having imbalances of certain neurotransmitters can cause cognitive impairment. A neurotransmitter is a chemical which is secreted by “presynaptic” neurons. The neurotransmitter then binds to a receptor on another neuron, and in order to get to the “postsynaptic neuron” the neurotransmitter must cross something called a synaptic cleft. However, numerous things can go wrong with neurotransmission, as the neurons can produce too many or too few neurotransmitters, or the neurotransmitter might not get broken down quick enough, or vice versa.
How does one develop neurotransmitter imbalances? There can be numerous factors, including a hormone deficiency, or blood sugar imbalances. For example, estradiol (the most dominant estrogen) modulates the serotonin receptors in the brain (6) (7). As a result, if someone with low estrogen levels takes a 5-HTP supplement in an attempt to increase serotonin, this might not be effective until the estrogen deficiency has been corrected. So this is one way in which a hormone imbalance can affect the neurotransmitters. Progesterone can also influence the neurotransmitters, as studies show that it can affect both serotonin and dopamine (8) (9) (10), as well as GABA (11) (12).
But how can one detect and then correct neurotransmitter imbalances? Well, testing for neurotransmitters can be a challenge, as while urinary testing is used by some natural healthcare professionals, it’s important to remember that this isn’t looking at the levels of neurotransmitters in the central nervous system. This doesn’t mean there isn’t some value with these tests, as while I don’t specifically recommend neurotransmitter testing to my patients, at times I’ll recommend an organic acids test, which is a urine test and evaluates some of the neurotransmitter markers.
As for how to correct neurotransmitter imbalances, many doctors will recommend giving the precursors to the neurotransmitters if they suspect a certain deficiency. For example, if they suspect low serotonin levels then they commonly will recommend tryptophan or 5-HTP. I have done this as well in the past, but what’s important to keep in mind is that certain nutrients are required for the enzyme reactions to form these neurotransmitters. For example, many people have low iron levels, yet iron is necessary for the conversion of tryptophan to 5-HTP. Now of course someone can choose not to address the iron deficiency and just take 5-HTP, but besides the fact that iron has many other important roles, other nutrients are required for the conversion of 5-HTP into serotonin.
3. Brain inflammation. Just like many people have gut inflammation, having neuroinflammation, specifically brain inflammation, is also common. There can be numerous causes of brain inflammation. Obviously a head trauma can lead to neuroinflammation, but other factors include blood sugar imbalances, a gluten sensitivity, toxins, and a leaky blood brain barrier. I have spoken numerous times in past articles and blog posts about having a leaky gut, and this is when the integrity of the intestinal barrier system is compromised. Similarly, one can have a leaky blood brain barrier, which can cause the symptoms associated with brain fog.
But how does someone develop a leaky blood brain barrier? Well, some of the same factors that can cause a leaky gut can also cause a “leaky brain”. This includes stress (13) (14), a gluten sensitivity (15), excess alcohol consumption (16) (17), and certain infections (18). Heavy metals such as aluminum, mercury, and cadmium can also cause an increase in permeability of the blood brain barrier (19) (20) (21) (22).
How can one determine if they have a leaky blood brain barrier? Well, there are a few different methods of determining this. There is a test by the company Cyrex Labs called the blood brain barrier permeability test, which tests for antibodies found when someone has a compromised blood brain barrier. However, another method is through something called the GABA challenge, which I learned through the work of Dr. Datis Kharrazian. This involves swallowing a 1,000 mg GABA supplement during the day, and if you feel different (either a calming effect or more anxious) then this is an indication that you have a compromised blood brain barrier. The reason is because most GABA supplements normally don’t cross the blood brain barrier, and so if someone takes GABA and has an intact blood brain barrier they shouldn’t feel any different.
However, it’s important to understand that some types of GABA supplements can cross the blood brain barrier. For example, a GABA product called Phenibut is able to cross the blood brain barrier due to the addition of a phenyl ring. And so someone who has an intact blood brain barrier would expect to notice a change in the symptoms when taking something like this. As a result, if you want an accurate GABA challenge you would want to take a GABA supplement that doesn’t have a phenyl ring.
4. Stress. Dealing with a great amount of stress can cause many different health issues, and it can lead to brain fog symptoms as well. Although some sources I’ve read claim that chronic stress can increase the permeability of the blood brain barrier, I was only able to find information showing that acute stress can cause a “leaky brain” (23). The hippocampus is part of the brain that is involved in memory, organizing, and storing, and there is evidence that chronic stress can have a negative effect on the hippocampus (24) (25). This is due to the effects of the elevated cortisol levels, and can cause or contribute to the symptoms of brain fog. One study did show that atrophy of the human hippocampus is reversible if the cortisol levels are decreased (26).
5. Blood sugar imbalances. Because glucose is the fuel source of the brain, having blood sugar imbalances can lead to symptoms of brain fog. As you can imagine, this is common with hypoglycemia, which involves low blood sugar levels, and is why many people with this condition feel significantly better after eating. However, high blood sugar levels can also cause symptoms of brain fog. Many people will develop insulin resistance, which is when the body becomes resistant to the effects of insulin. This also can cause brain fog symptoms, although unlike the person with hypoglycemia, the person with insulin resistance usually feels worse after eating. I discussed these conditions in greater detail in my blog post entitled “Insulin Resistance, Hypoglycemia, and Thyroid Health Part 1 and Part 2“.
In addition, blood sugar imbalances can also affect the production of the neurotransmitters. The reason for this is because certain amino acids that are necessary for the formation of the neurotransmitters need to be transported across the blood brain barrier. However, normal blood sugar levels are important for this transportation to occur. If someone has blood sugar imbalances then this will affect the production of neurotransmitters. I also mentioned earlier how activation of microglia cells can cause neuroinflammation, and blood sugar imbalances can cause the activation of these cells, which in turn can cause brain fog. So there are numerous ways in which blood sugar imbalances can lead to brain fog.
Natural Treatments For Brain Fog
If someone is experiencing brain fog then they will want to address the following imbalances.
1. Normalize the thyroid hormones. Low thyroid hormone levels are more commonly associated with brain fog symptoms than elevated thyroid hormone levels. As a result, if someone with low or depressed thyroid hormone levels has brain fog then the thyroid hormone levels need to be normalized.
2. Correct neurotransmitter imbalances. In many cases, low levels of neurotransmitters can lead to the symptoms of brain fog. So for example, having low levels of serotonin, GABA, or acetylcholine can cause brain fog. However, high levels of certain neurotransmitters such as epinephrine and norepinephrine can also lead to brain fog symptoms.
3. Lower cortisol levels and improve your stress handling skills. I spoke about how stress can affect the blood brain barrier, thus leading to a “leaky brain”. And so I would do everything you can to reduce your stress levels.
4. Correct blood sugar imbalances. Since blood sugar imbalances can lead to the symptoms of brain fog it is important to address this if it is an issue. If you have insulin resistance or hypoglycemia I would make sure to read my blog posts on these topics.
5. Reduce your toxic load. I mentioned earlier how heavy metals can increase the permeability of the blood brain barrier, and so you of course want to minimize your exposure to these. However, I didn’t mention that other toxins can also disrupt the integrity of the blood brain barrier, such as PCBs (27) (28). And I’m sure there are many other toxins which disrupt the blood brain barrier, yet haven’t been proven to do so. There is even evidence that exposure to electromagnetic fields can disrupt the permeability of the blood brain barrier (29). So this is yet another reason why you need to minimize your exposure to environmental toxins.
6. Repair the blood brain barrier and eliminate brain inflammation. There are numerous compounds which decrease brain inflammation. Curcumin and resveratrol are two of the more well researched nutrients which can help with this. One study shows that resveratrol that is given after traumatic brain injury results in a decrease in neuroinflammation (30), while another study showed that resveratrol can inhibit activated microglia (31). A few studies have shown that resveratrol can help to maintain the integrity of the blood brain barrier (32) (33). Curcumin not only can help greatly with neuroinflammation, but it also passes through the blood brain barrier and can modulate the neurotransmitter levels in the brain (34). Another study showed that curcumin weakens the inflammatory responses of brain microglia (35). Curcumin can also decrease the permeability of the blood brain barrier (36).
However, other nutrients can also decrease brain inflammation. Green tea catechins have been shown to have neuroprotective activities and to decrease inflammation (37). Another study showed that green tea polyphenols have protective effects on age-related neurodegeneration (38). And the polyphenols in green tea has been shown to be neuroprotective against damage of the blood brain barrier (39). Rutin is a flavonoid that can prevent cognitive impairments by decreasing oxidative stress and neuroinflammation (40), and it has an inhibitory effect against microglial activation (41). Rutin can also help to decrease the permeability of the blood brain barrier (42). Luteolin is another bioflavonoid that can help with neuroinflammation by inhibiting microglial activation (43). Docosahexaenoic acid (DHA), which is found in fish and fish oil supplements, can also modulate microglia activity and reduce neuroinflammation (44) (45), and both DHA and vitamin D can offer protection against damage to the blood brain barrier (46) (47).
In summary, brain fog is common in people with thyroid and autoimmune thyroid conditions. Some of the common causes of brain fog include low thyroid hormone levels, neurotransmitter imbalances, brain inflammation, stress, and blood sugar imbalances. Infections and environmental toxins can also compromise the blood brain barrier, leading to the symptoms of brain fog. As a result, when attempting to treat brain fog naturally it is important to address any of these problems. When dealing with brain inflammation you can consider taking curcumin, resveratrol, and drinking green tea. Docosahexaenoic acid (DHA) and vitamin D can also play important roles in maintaining the integrity of the blood brain barrier. Rutin and luteolin can also be beneficial.