Brain Fog: 5 Potential Causes

Brain Fog: 5 Potential Causes

When it comes to being mentally sharp, we all have good days and bad days. There are times our minds seem to fire on all cylinders, but in other moments we may feel sluggish or forgetful. That’s a completely normal thing and just part of life. However, if our minds feel constantly unclear, tired, or slow, that could point to a different problem. Today we look at an issue called brain fog, a somewhat mysterious phenomenon that can cause our thinking to become cloudy. We will take a look at what scientists are saying about the cause of brain fog and some effective ways that you can help clear it up for good.

Article At-A-Glance:

  • Brain fog is a neurological issue characterized by poor memory, impaired speech, trouble with calculation and mental functions.
  • Stress, mood imbalance, poor gut health, fatigue, low blood sugar and inflammation can all play a role in causing brain fog.
  • Eliminating stress, sleeping more, exercising, and dietary changes can all help clear brain fog and get you feeling back to normal.


What Is Brain Fog?

Although brain fog itself is not a medical condition, it is a very real thing that affects millions of people. Different people may experience brain fog in different ways, but it can be generally described as a disturbance or impairment in cognitive function. Some people report feeling ‘off’ in their thinking, while others point to more specific issues. Here are some common signs or symptoms of brain fog.

  • Diminished memory and difficulty recalling information (source.)
  • Slurred speech or issues understanding or using language.
  • Trouble with mental calculation.
  • Difficulty with executive functions, such as planning, organizing or problem solving (source.)

Let’s be clear about one thing: brain fog is different than just feeling mentally tired. Everyone has mental difficulty when facing a tough situation. But brain fog is a persistent haze and cloudy thinking that is unrelated to momentary circumstances.


What Causes Brain Fog?

Nobody can point to one specific cause of brain fog. However, there are a number of factors that can contribute to it. Let’s look at a few of them.



Stress can not only take an emotional toll on you, it can also be at the root of many health problems, including brain fog. Part of the reason for this is that stress activates our ‘fight-or-flight’ response, which releases hormones and chemicals that can cloud your brain’s ability to concentrate, withdraw past memories, or learn new information (source.) Adrenaline, cortisol, and other stress-related chemicals can focus your brain on danger avoidance. This can interfere with your higher-order thinking (source.)


Mood Imbalances

Low mood levels can actually flatten out your brain’s signalling, causing your neurons to fire with less frequency. Mood imbalance can also create lower levels of ‘feel-good’ neurotransmitters, such as dopamine and serotonin. Decreased amounts of these key neurotransmitters can make it difficult for your mind to stay sharp and focused as well as remember clearly (source.)


Poor Gut Health

As we’ve spoken about in other articles, the gut and the brain are very closely related--so much so that some scientists refer to the gut as the ‘second brain.’ Many health experts believe that one of the common causes underlying brain fog is poor digestive health. Dr. Datis Kharrazian, researcher and professor at Loma Linda University School of Medicine, says that issue may boil to a condition called intestinal permeability or ‘leaky gut.’ Leaky gut is thought to be an issue where the intestinal lining becomes overly porous and allows toxins, undigested food and pathogens into the bloodstream (source.) These pathogens create systemic inflammation and another problem he calls ‘leaky brain.’

Many nutritionists and holistic doctors believe that leaky brain is the key to the gut/brain fog connection. They theorize that leaky gut allows inflammatory proteins into the bloodstream, which damages the blood-brain barrier. As this happens, proteins and other invasive elements are allowed into the brain, which causes an inflammatory response--and thus, brain fog (source.)

It should be noted that not all scientists agree with this theory. Some debate continues as to whether or not leaky gut/leaky brain accurately describes this process of inflammation in the body. Despite the debate, many brain fog sufferers find relief as their gut health improves. Later in this article, we will cover some things you can do for your digestion that may help boost mental clarity and performance.



Fatigue and brain fog can go hand in hand. If fatigue is something you struggle with persistently, then you are likely well acquainted with brain fog also. Fatigue is a mysterious complaint that often baffles doctors and leaves patients feeling dissatisfied. Similarly, the relationship between fatigue and brain fog is also unclear in the scientific community. There are however, a number of theories that could explain why fatigue issues can often lead to cognitive dysfunction. Here are just a few:

  • Poor sleep, insomnia or nonrestorative sleep could be a contributor.
  • There may be abnormal blood flow in certain parts of the brain.
  • There may be abnormal connectivity patterns between different regions of the brain.
  • Certain neurotransmitters (brain chemicals) may be functioning abnormally.
  • Brain fog could be a result of premature aging of the brain (source.)


Blood Sugar Imbalance

Low blood sugar can not only create mood swings, it can also lead to cognitive issues, causing your memory, focus, and clarity to go haywire (source.) Your brain is built to require a steady source of glucose in the blood to function optimally. When your blood sugar gets too low (say from skipping a meal), or when it gets too high (from eating too much sugar), brain fog may come as a result (source.)

Your brain cells (neurons) need glucose more than any other cells in the body (source.) As insulin absorbs glucose out of the blood, there is no fuel for your neurons, which can leave you feeling cloudy, unfocused, and lightheaded (source.)

Also, changes in blood sugar can affect the use and metabolism of certain neurotransmitters. Sharp spikes can raise serotonin and GABA, which creates a sense of drowsiness. As blood sugar rapidly drops, hormones such as adrenaline and cortisol are released to help buffer the sudden decrease in glucose (source.) All of this basically can keep your brain from functioning well, making it difficult to think critically, recall facts, and converse properly (source.)


Understanding The Bigger Picture (Inflammation and Brain Fog) 

In addition to chemical and hormone imbalances, the root of brain fog at the cellular level is inflammation. Inflammation is caused by low-grade overactivity of the immune system and can create cognitive impairment, insomnia and mood-related issues (source.)

It’s important to note that inflammation is not a bad thing in and of itself. We all need inflammation because it helps our body fight off infection and heal--this is called our inflammatory response (source.) The issue, however, is when inflammation becomes imbalanced (i.e. chronic inflammation.) Too much inflammation or an inappropriate inflammatory response can damage our bodies tissue and even our brains (source.)

In order to learn how inflammation creates brain fog, it’s important to understand a little about how the immune system works in the brain. According to Dr. Kharrazian, our brain’s immune response is controlled by cells called microglia. These tiny organisms ‘turn on’ an inflammatory response under specific circumstances. Here are a few:

  • Whenever there is head trauma.
  • If blood sugar is unregulated.
  • If blood is not circulating properly to the brain
  • If there is inflammation outside the brain (i.e. gut inflammation.)
  • If there is hypersensitivity to environmental pollutants (source.)

When microglia are turned on, so is inflammation. When inflammation is present in the brain, it can cause neurons to fire more slowly, which can hamper your reflexes, mental sharpness and recall abilities. These sluggish neurons also cut off the production of energy in the cells, which can lead to fatigue (source.)

A number of factors can lead to inflammation, including lifestyle and diet. Later in this article, we will cover some practical ways that you can help lower excessive inflammation in your body.


6 Ways To Banish Brain Fog

If brain fog is an issue that you’re facing, there is good news. Brain fog can be many times relieved by a combination of factors, several of which come down to lifestyle, diet, and exercise. Here is a list of ways that you can tackle brain fog head on.


Find Ways To De-Stress 

Many people who struggle with issues like brain fog or fatigue also struggle (or have struggled) with stress and overstimulation. More than ever, we are surrounded by people and devices demanding our time and attention. To clear your brain fog, find a way to free up your mental space. This could look like taking up a restorative practice like meditation or prayer. It could mean cutting out unnecessary social media time. Whatever it looks like, finding a way to still your mind will be key to restore balance to your brain fog.

It almost seems too easy to say “relax” when it comes to dealing with health issues. But in the case of brain fog, that may be exactly what you need to do. Because stress can interfere with the body’s ability to fight inflammation, being intentional about relaxation could be key to getting back to normal. If you want to get serious about cutting stress, make a list this week of ways you can make rest a priority. Brainstorm (and Google) stress-busting techniques. You may start with taking a 10-minute walk in the evening, or drawing a bath instead of taking a shower. You might also try to think of ways you can spend more time with others since close relationships are linked to lower stress levels. Get creative and find your own ways to make life simpler and peaceful.


Sleep More

It may seem obvious, yet to so many Americans it is not! According to a massive survey of over 20,000 US citizens, 79% reported getting less than the recommended 7-8 hours of sleep per night (source.) It’s no wonder we’re feeling tired. But how can sleeping more combat brain fog specifically? Regulating and maximizing your sleep can have major cognitive benefits, including heightened memory, attention and mood (source.) Consider this quote from Dr. Lawrence Epstein, instructor at Harvard Medical School: "You really can make up for lost sleep and restore focus and clarity. You can lose the brain fog within a week. But start now; the longer you have bad sleep, the longer it will take to catch up. (source.)"

Scientists are finding more and more evidence that it pays to take sleep seriously, but here is something to take note of: research shows that sleep quality is actually more important than sleep quantity (source.) The brain creates new neural pathways while you sleep to prepare for new information. High quality sleep can boost your attention, problem-solving and decision-making skills (source.)


Exercise Regularly

Getting active can work on a number of levels to reduce brain fog. As you start to work out, your blood vessels open up and your brain starts to receive more oxygen. This delivers more nutrients to your brain, and it can have a performance-boosting effect on your ability to think. Research shows that even a short 10 minute burst of exercise can deliver brain-boosting benefits, including greater memory function (source.)

Exercise also combats brain fog by up regulating BDNF (Brain-Derived Neurotrophic Factor.) BDNF is a molecule that plays an important role in your brain’s function, and some studies have linked brain fog and low BDNF levels. Research has also found a connection between BDNF and brain size. One study found that the increase in BDNF from exercise actually increased the size of the hippocampus, a portion of the brain responsible for memory function (source.)

Finally, exercise triggers a release of a number of key neurotransmitters that can combat brain fog. Working out spurs the release of helpful chemical messengers called cytokines as well as ‘happy chemicals’ called endorphins (source.) Both of these chemicals bathe and rejuvenate the brain and can play a role in relieving mental cloudiness.

What are the best exercises for brain fog? In general, all exercise is good exercise, but some may be particularly beneficial. Meditative exercises like yoga and tai chi are great for boosting mental clarity (source.) Also aerobic exercises like swimming, biking, dancing, and jogging can help push out brain fog. Finally, anaerobic exercises like weight lifting can be helpful also because they release high amounts of BDNF.


Gut Health Repair

Some health experts put so much emphasis on gut health that they believe healing your gut is a prerequisite for getting rid of brain fog. While that isn’t true in every case, many people do find their brain fog relieved when they start addressing their digestive health. What does that look like? An easy place to start is simply adding a probiotic to your daily routine. Probiotics affect your gut microbiome, which is a fancy way of saying that it puts good bacteria in your digestive tract. Continuing to take probiotics can strengthen your immune system and digestive function, which could have a powerful effect downstream on your mental clarity and thinking abilities. Another way to boost your microbiome is to eat foods rich in probiotics, such as yogurt, kambucha, kefir, and fermented foods such as sauerkraut, miso, and kimchi.

Another way to help boost your digestion is to start taking an amino acid called Glutamine. Glutamine is a critical part of the immune system, and it can help strengthen your intestinal lining. It is commonly recommended for anyone who suspects they’re dealing with leaky gut (source.)

The final piece is to start changing your dietary habits, which we will cover next...


Change Your Diet

Diet is maybe the biggest factor in overall health, but it’s especially important when it comes to dealing with brain fog. In some cases, we may not even be aware of which foods may be triggering our cognitive issues.

Therefore, one place to start addressing brain fog is by eliminating “high-inflammatory foods (source.)” What are they? Here is a list of foods you can temporarily cut out to see if it improves brain fog:

  • Lectins — foods like legumes, beans, peas, lentils, and vegetables like eggplant, tomatoes and peppers.
  • Gluten
  • Wheat
  • Casein — including all dairy!
  • Yeast

If you’re really serious about brain fog, removing these foods from your diet could be a good test to see if food may be at the root of your cognitive issue (source.)

In terms of general dietary guidelines, here are some other things to keep in mind. Whenever possible, it is best to cut out unhealthy or ‘useless’ carbs found in many processed, starchy or sugary foods. On the other hand, it is a good idea to increase ‘brain-healthy’ fats, such as Omega-3 Fatty Acids. You can find Omega-3s in foods such as mackerel and salmon, as well as olive oil, canola oil and sunflower oil. If you’re not a big fan of those foods, you could try adding an Omega-3 supplement, such as this one. For more general guidelines on healthy brain foods, check out this article


Final Thoughts On Brain Fog

Although brain fog can be an irritating nuisance, it doesn’t need to be your constant companion. Integrating these strategies along with a healthy lifestyle can go a long way in increasing your mental clarity and performance. To learn more practical ways to take control of your brain health, keep reading our blog at


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