What Causes Brain Fog?

Brain fog is a common experience for many people. Although it is not a condition in and of itself, it typically occurs as a symptom generated from a wide variety of other conditions or circumstances. Let’s explore the many contributing factors by taking a look at the following questions…

Hi Cynthia, my name is Kathy, I always feel like I am spaced out or brain fog whatever you want to call it. I have been this way for a long time.I have numerous other symptoms as well.I am wondering if you could tell me what might be causing this. It is becoming harder and harder to deal with this. Thanks Kathy.

Hi Cynthia, I have been diagnosed with candida and adrenal fatigue. I am also blood type A and have gone back and forth with the candida diet and the blood type diet. I know for sure that grains, high carb veggies, fruit, caffeine, alcohol, beans, corn, dairy, soy eggs and nightshades all negatively effect me which makes me believe in the paleo diet. But it seems like the only animal flesh I can eat without getting fatigued and bogged down with brain fog is fish. With research I find out that the reason could be that I may have too little hydrochloric acid in my system, a congested liver, a healing reaction or it just might be that fish is the only thing I can have per blood type. I started today eating garlic, apple cider vinegar and have yet to do a coffee enema even though I’ve done so in the past. What can I do to help prevent the unrelenting brain fog and fogginess when I eat meats? Lauren

For those of you who may not be familiar with the term, brain fog refers to a “fuzzy,” “cloudy,” “spacey,” or “foggy” feeling within the brain. It typically impairs one’s cognitive functioning skills and is usually associated with mental confusion, forgetfulness, difficulty concentrating, short term memory loss, poor word recall, impaired problem solving abilities, a feeling of disconnection or detachment and/or lack of mental clarity.

Some people have bouts of brain fog that seem to come and go for no identifiable reason, while other people may live with it on a continuous day-to-day basis. Many people have brain fog and aren’t even aware of it, because they have been this way for so long, they think it is normal. For some it may be a mild annoyance, while for others it may be completely debilitating.

Causes of Brain Fog

The root cause of brain fog is disrupted neurotransmitters in the brain, which results in impaired brain function. Neurotransmitters are natural chemicals in our brain that are used for communication between cells. However, there are many factors that can contribute to this disruption. It’s usually a complex interaction of many of these factors, not just one.

Candida overgrowth

An overgrowth of Candida yeast is the most common cause of brain fog. The organism releases a variety of toxins like acetaldehyde and alcohol that impair neurotransmitters in the brain. Additionally, brain fog may intensify temporarily during die off, when organisms are killed due to changes in diet or the use of antifungals.

Environmental Toxins

Environmental toxins, including electrosmog, sick buildings, mold, pesticides, air fresheners, cologne, perfume, disinfectants, cosmetics, shampoo and other common everyday chemicals in your home disrupt and/or deplete neurotransmitters in the brain.

Heavy Metal Toxicity

Heavy metals like mercury, cadmium, arsenic, etc., which are commonly found in seafood, dental fillings, water, air and more, impair the production of neurotransmitters and thus result in brain fog.

Nutritional deficiencies or imbalances

The brain needs a wide variety of vitamins, minerals, amino acids, and fatty acids to function properly. If there are not enough or too many of a particular nutrient, then neurotransmitters are not produced or transmit properly, and brain dysfunction occurs.

For example, too much copper can result in confusion, disorientation and manic mood swings. However, not enough copper can also result in brain fog, as the brain cannot produce neurotransmitters or function properly without adequate copper levels.

Neurotransmitters cannot be produced without adequate intake of amino acids, which are derived from protein, and much of the population is protein deficient and has a variety of other nutritional deficiencies.

Food sensitivities

Disrupted neurotransmitters and impaired cognitive functioning is one of the most common symptoms of food sensitivity or intolerance.

Adrenal Fatigue

In adrenal fatigue the adrenal glands that are depleted don’t produce enough cortisol to meet the demands of the body, this puts the body and mind under tremendous stress and depletes its neurotransmitter levels.


Low thyroid function inhibits the production and alters the function of some neurotransmitters, thus resulting in many of the brain impairment symptoms accompanying hypothyroidism, like brain fog.

Chronic stress

When we are under stress, we need high levels of neurotransmitters like dopamine, acetylcholine, endorphins, and serotonin to counteract the effect of the stress. So if there is chronic stress, then our reserves of neurotransmitters will be depleted, thus leading to poor brain function.

Poor diet

Sugar, caffeine, artificial sweeteners, food additives, dyes, white flour, preservatives and other junk food all alter function of the neurotransmitters and can lead to depletion. This is true of a diet that is too high in complex carbohydrates like grains, potatoes and legumes as well. The brain needs lots of protein and fat in order to produce neurotransmitters and for proper neurotransmission.


When blood sugar levels drop, as they do in hypoglycemia, then so do neurotransmitters and the inevitable changes in mood and brain function.

Diet Transition

When one is switching over from a high carb diet to a healthier high protein diet as I recommend in the Paleolithic diet, there can be a temporary adjustment period in which brain fog may occur. If you’ve been eating a high carb diet for some time, and then you remove them, it takes time for the body to switch over from running on carbs to running on protein and fat. There may also be an increase in fatigue and other symptoms. Typically this is a transitional phase that lasts 2 or 3 weeks.


Other causes of brain fog may include an overgrowth of other unfriendly organisms like bacteria, h pylori, lyme or parasites, cavitations or other dental issues, menopause, misalignment of the spine, lack of oxygen and dehydration.

Brain fog commonly occurs with multiple sclerosis, lupus, chronic fatigue syndrome, multiple chemical sensitivity, fibromyalgia, and other chronic health conditions, but the important point to be aware of here is that these conditions occur because of all the factors that we just listed above.

What to Do About Brain Fog

Clean up the diet. Get rid of the caffeine, sugar, white flour, artificial sweeteners, additives, preservatives, etc. Reduce or eliminate grains and potatoes.

Eat more meat. Follow the Paleolithic diet.

Avoid alcohol

Stay hydrated

Keep blood sugar stable with frequent meals that are high in protein and good fats

Address Candida and other organisms

Identify food sensitivities.

Assess nutrient status and replenish deficiencies

Reduce exposure to environmental toxins


Assess thyroid and adrenal glands and address accordingly

If in a diet transition, give it a few weeks to stabilize

Use deep breathing exercises, mindfulness meditation, yoga etc.,to reduce stress

Kathy in your situation, you need to start exploring all the possible causes and see which ones are applicable to your situation.

Lauren, in your situation, you already know you have Candida and adrenal fatigue, so these are your likely culprits. The meat situation is probably temporary as your body is switching over to run on protein and fat and should subside in a few weeks. Please read my page on the  blood type diet, as I am not a believer. You could also try eating smaller portions of meat and take a look at my How to Eat Meat Again post.

Additionally, you may be having die off on the high meat diet, and that too will subside shortly. Die off can be reduced with enemas, colon cleansing with *Oxy-Powder®., charcoal supplementation, bentonite clay and exercise. Many people with Candida and adrenal fatigue are low in digestive enzymes, so they should always be part of the recovery path.

Best Regards,

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