The gut-brain connection.

Science often refers to your gut as your “second brain.” Your gut and brain are actually formed from the same fetal tissue when you were growing in your mother’s womb, and continue their special bond throughout your whole life through what is known as the gut-brain axis. So, in order to heal the brain we need to look at the other end of this axis for clues.

For anyone in the wellness world, leaky gut syndrome is not a foreign health problem. Leaky gut happens when your gut lining is damaged and can lead to a whole slew of digestive and other health issues. Occludin and Zonulin are two proteins that govern gut permeability as well as the permeability of your blood-brain barrier. Elevated antibodies to these proteins can indicate that there has been damage to your gut and your brain. The gut-brain connection becomes all too real here by turning leaky gut into “leaky brain.” Pleasant sounding, huh?

In my clinic, it’s not uncommon that I have a patient come in looking for help with depression or brain fog and have further diagnostic testing reveal that they also have leaky gut syndrome. It just goes to show that digestive problems can still be a factor even if you aren’t experiencing symptoms.

Your brain on inflammation.

To make matters worse, with increased permeability comes increased inflammation in the gut. Inflammation is a necessary part of a healthy body to fight off infections or when you get a cut. However, chronic inflammation wreaks havoc on your health. So much so that a whole area of medical research known as “the cytokine model of cognitive function” is dedicated to researching how inflammation, specifically inflammation of the brain, is correlated with brain problems.

This increased inflammation doesn’t help your blood-brain barrier either. The microRNA-155 molecule is elevated (4) with high inflammation and ends up creating gaps in the blood-brain barrier that lets bacteria and other toxins slip through. Your brain’s immune system has to work in overdrive to fight off these invaders and ends up creating a cascade of inflammation to your brain in order to try to protect it. This inflammatory oxidative stress in the hypothalamus of the brain is the underlying cause of brain fog and why you can’t figure out where you last left your keys.

The Top Triggers of Brain Fog

1. Thyroid problems

Thyroid hormone imbalances have been shown (5) to cause inflammatory-immune responses. Your thyroid works by receiving the proper messages from the brain through the hypothalamic-pituitary-thyroid (HPT) axis, so if your hypothalamus is inflamed, it causes dysfunction in the brain-thyroid axis. The end result? A vicious cycle of inflammation.

2. Adrenal fatigue

Just as you have the brain-thyroid axis, you also have the brain-adrenal (HPA) axis. Dysfunction in your adrenal-based circadian rhythm (6) can manifest as adrenal fatigue, when the stress hormone cortisol runs wild, depressing your immune system. As with thyroid issues brain fog can be both the cause and the effect of adrenal fatigue due to this particular brain-hormone connection.

3. Viral infections

Low-grade chronic viral infections such as Epstein-Barr virus (EBV) are linked to a wide range of inflammatory problems like chronic fatigue syndrome. One of the many issues viral infections can cause is to block the body’s vitamin D receptors, so you can’t use the vitamin D you take in – a particular talent of the villainous EBV, which has been shown (7) to do just this.

4. Leaky gut syndrome

Your gut and brain are inextricably linked – they are even formed from the same fetal tissue when you were growing in your mother’s womb. In the medical literature, leaky brain syndrome is highly associated with leaky gut, and an increase in gut bacterial toxins called LPS, has been shown (8) to affect brain inflammation.

5. Candida overgrowth

Excess yeast in the microbiome, particular those yeasts that are in the candida genus, increases the inflammatory cells (9) IL-1, IL-6, and TNF, which can contribute to too much inflammation in the body and brain.

6. Histamine intolerance

Some people – particularly people with the gut problems mentioned above – are more prone to something called histamine intolerance. This happens when the body doesn’t break down the immune cell histamine properly, or overreacts to its presence, which causes (10) a release of superoxide, a nasty free radical that causes a lot of inflammatory damage that can affect the brain.

7. Poor sleep

If you’re not sleeping well at night, you don’t need me to tell you it affects your brain health. Sleep loss decreases (11) the inflammation-fighting antioxidant glutathione, which increases oxidative stress in the hypothalamus, causing brain fog.

8. Methylation impairments

Methylation is a biochemical process that happens 1 billion times every second in your body. Your organs, including your brain, depend on methylation for health and detoxification. Many people (myself included) have genetic methylation mutations, such as the MTHFR mutation, that impede this detoxification process, increasing the likelihood of systemic inflammation.

9. Sugar

It might be tasty (especially when you are addicted), but refined sugar in all its many guises is everywhere, and it is brain poison. I believe that if your goal is a healthy brain, refined sugar should be the first thing on your list to cut out of your life. Why is it so bad? There are primarily two mechanisms by which refined sugar can have a toxic effect on your brain function.

First, sugar actually suppresses activity of a key growth hormone in the brain called brain-derived neurotrophic factor, or BDNF. BDNF is highly beneficial to a properly functioning brain, but levels are notoriously low (12) in people with depression. Second, eating sugar-containing foods triggers a complex cascade of chemical reactions in your body that will up-regulate chronic systemic inflammation. Over time, inflammation will disrupt the normal functioning of your immune system and wreak havoc on your brain. The good news is that once you get sugar out of your diet, naturally sweet foods like fruit will taste as sweet as candy and you will no longer crave the refined junk.

10. Grains

You may have been told that whole-grains are healthy, but refined or whole, there are many ways eating grains can negatively affect your brain. Grains can cause blood sugar instability that, just like refined sugar, can result in inflammation. Grain proteins like gluten (13) and lectins (14) are also well linked in the literature with gut inflammation and permeability, which can in turn affect brain inflammation and blood-brain-barrier permeability.

11. Artificial sweeteners

Those little yellow, blue, and pink packets you might put in your coffee or sprinkle on your oatmeal (see above item on grains) are wreaking havoc on your mood as well as your microbiome. In a double-blind study (15) on the effects of aspartame on people with mood disorders, findings showed a large increase in serious symptoms in those using artificial sweetener products containing aspartame. Aspartame is made with the isolated amino acid phenylalanine, which is neurotoxic and goes directly into the brain, depleting your serotonin levels and possibly worse. When you lower serotonin, it can trigger a variety of different mood disorders. Also, artificial sweeteners have been documented to cause microbiome dysbiosis, again impacting the gut-brain axis and potentially impacting mood. Both of these factors mean that for the sake of your brain, it’s best to stay away from the artificially sweet stuff.

12. MSG

Monosodium glutamate or MSG is a processed flavor enhancer that is commonly added to many convenience food such as soups, processed meats, and frozen dinners, and is also a ubiquitous ingredient in restaurant Asian food. While some people claim not to be affected, MSG is an excitotoxin which can affect your brain chemistry (16) and your body’s endocrine (hormone) system. Sometimes it’s difficult to spot a food containing MSG because it hides in food ingredient labels behind many different names, including glutamic acid, glutamate, autolyzed yeast protein, textured protein, natural flavors, and hydrolyzed corn. This is just one more reason why natural whole foods without long ingredients lists are always the best choice.

13. Toxic household products

The world is undoubtedly far more toxic than it has ever been before, and we all have toxins in us and around us. Some of these we can do little about, but there are some effective things we can all do that are within our immediate control. For example, chemicals that are used in common household cleaning products have been linked to altered brain function. Switch to natural, plant-based cleaners without industrial chemicals and you have made a big step in the right direction. Also, the majority of beauty products used today are also filled with chemicals that will literally interfere with your body’s hormones, affecting how you feel and think.

These ingredients in beauty products are anything but pretty. The Environmental Working Group found that one in eight of the 82,000 ingredients used in personal care products are industrial chemicals, many of them linked to hormone and mood disorders. Remember, your skin is your largest organ and is highly absorptive. If you can’t eat it, don’t put it on your skin. Many beauty products and personal hygiene products are now available that are plant-based and contain all-natural ingredients. But good old coconut oil alone can replace a lot of beauty products.

14. Heavy metals

Conventional doctors don’t tend to think about chronic heavy metal toxicity as a factor in brain problems, but in my practice, I find this can have a profound effect. Chronic heavy metal levels of mercury or lead (as opposed to acute levels) can be an insidious issue for chronic conditions like depression, anxiety, chronic fatigue, and brain fog, and have been linked (17) to almost any mood or brain disorder. One reason why chronic heavy metal toxicity goes undiagnosed is because unlike acute poisoning, during which heavy metals are circulating in your blood, chronic metal toxicity has leached into your body’s tissues like your bones, fat, and brain. This can make it harder to find because a blood test might come back normal. Proper diagnostic testing is essential for this issue. Pulling the metals from the body using chelating agents and measuring those levels using a Urine Heavy Metals test is how I uncover this piece of the puzzle for my patients.

How Do I Find Out If I Have This Problem?

If you think you are suffering with brain fog or a "leaky brain" start here to know more definitively.

1. Ask your doctor about getting labs to asses your blood-brain barrier.

Blood-Brain Barrier Proteins: I run these labs to help determine if the blood-brain barrier has been breached.

Occludin and Zonulin: Blood tests can measure antibodies against these two proteins, which can suggest both brain and gut permeability.

Homocysteine: High levels of this amino acid have been linked (18) with blood-brain barrier damage. Learn more about why you should get your homocysteine levels tested in my previous article.

Test for other common contributors to poor brain health: Chronic inflammation accelerates your brain’s aging. High blood sugar is one risk factor (19) for blood-brain barrier destruction.

2. Ask your doctor about microbiome labs.

An unhealthy gut can lead to an unhealthy brain, so looking at the state of the gut (or “second brain”) could shed light on what’s going on in your brain. Bacterial imbalances and yeast overgrowth are two conditions that can have neurological implications – for example, anxiety and depression have been linked (20) to lower levels of bacteria called Lactobacillus helveticus and Bifidobacterium longum.

Functional Medicine Tools to Overcome Brain Fog

So what are you supposed to do about that dastardly brain fog? Here is my prescription:

1. Find out your inflammation levels.

I run several different labs to assess where my patients’ inflammation levels are:

TH1/TH2/TH17-dominance test

CRP

Homocysteine

Leaky-gut labs

Blood-brain barrier labs

Methylation genetic labs

These labs will tell you what you’re up against, so you and your doctor can have a more specific idea about what to target.

2. Reduce inflammation.

There are many natural ways to soothe inflammation back down to baseline levels. Incorporating turmeric into your daily meal plan and swapping out inflammatory foods with nutrient dense substitutes are just a couple ways you can start healing today.

3. Heal your gut.

A leaky gut takes anywhere from 12 to 24 months to fully heal. To start this healing journey, bring in food medicines like bone broth and probiotic-rich fermented foods like sauerkraut to sooth damaged gut lining and provide your microbiome with good bacteria.

4. Add in herbs.

There aren’t many things that adaptogens can’t help with. These herbal and plant medicines bring balance back to every system in the body, including the brain. Holy basil is one of my favorites for brain fog since it works to regulate cortisol (21) and increase cognitive function. Lion’s mane mushrooms are also a top choice of mine due to their uber-powerful nerve growth factors (NGFs) that help to regenerate and protect brain tissue. Research has shown that cognitive function improves with the addition (22) of this adaptogenic mushroom.

Adaptogens like astragalus (23) and reishi (24) are also two great tools to balance the immune system and gently boost energy.

5. Indulge in a sauna session.

Infrared saunas are a great therapeutic way to bring down inflammation levels. A 30 minute sauna session a few times a week is a relaxing way to de-stress while bringing down inflammation.

6. Boost your vitamin D.

Vitamin D deficiency can contribute (25) to decreased memory as well as brain fog. Sunshine is your most bioavailable source but it’s not always possible to get outside often, especially if you live in a place with harsh winters. In that case, turn to food medicines like salmon, tuna, and mackerel and pair them with foods loaded with fat-soluble vitamins A, E, and K2 to increase the bioavailability of vitamin D.

7. Make your life a cleanse.

There are many ways to avoid toxins in your everyday life. These can also help mitigate what’s passing through a damaged blood-brain barrier while you heal.

8. Don’t miss your Zz’s.

We live in a culture that doesn’t always put enough value on sleep as it should. But sleep is crucial to our mental clarity. It only makes sense that a lack of sleep leads to a foggy next day since it increases (26) the oxidative stress in your brain’s hypothalamus.

9. Use plant medicines.

Try adding some gynostemma (27) and gotu kola (28) to your morning. These two plant medicines have been shown to decrease oxidative cellular damage and increase cellular energy, paramount to overcoming brain fog. Just add them to your smoothie, or take supplements.

10. Support your methylation.

Methylation runs primarily on B vitamins, so taking activated B vitamins, like B9 L-Methylfolate (L-5-MTHF) and B6 Pyridoxyl-5-Phosphate (P5P), will support this crucial process. You can also read my other tips on supporting methylation in this article on the subject.

11. Go bright or go home.

In addition to providing you with the most bioavailable source of vitamin D (which is likely to be lacking in those with brain fog), the sun also provides (29) healing infrared light, which is essential to balancing the immune system and calming inflammation levels. On sunny days, spend at least 30 minutes outside and soak up the rays.

12. Try targeted natural medicines.

Various research has shown that natural compounds such as apigenin, (30) baicalein, (31) catechins, (32) curcumin, (33) luteolin, (34) resveratrol, (35) and rutin (36) can reduce brain inflammation levels. The correct dosage will be case specific, so work with a functional medicine doctor to figure out which types and what dosages are best for you (what works for someone else may not be right for you).

13. If you don’t already, start exercising.

Aerobic exercise has been shown (37) to increase brain-derived neurotrophic factor (BDNF), which promotes the health of brain and nerve cells.

14. Dial back the alcohol.

Alcohol is stressful for the brain, and some studies suggest (38) it can damage the blood-brain barrier, so while you are working on healing this all-important protection, take a break from the booze.

15. Avoid known brain zappers.

Be sure to steer clear of common brain-damaging foods such as highly refined and sugary foods, as well as exposing yourself to other toxins.

16. Wrangle your stress.

Research suggests (39) that acute stress increases blood-brain-barrier destruction. Tai chi, yoga, and mindfulness meditation can all be effective ways to mitigate the stress in your life.

17. Try an elimination diet.

A poor diet is one of the main drivers of chronic inflammation. When you’re choosing your meals, remember that everything you eat either feeds disease or fuels health. If you’re struggling with inflammation, I always recommend trying an elimination diet to identify any food sensitivities or allergies you might have. For a detailed guide to eliminating foods and how to reintroduce them, check out my book The Inflammation Spectrum.

18. Stop snacking.

With drive throughs, vending machines, and endless aisles of convenient and delicious snacks, food is always readily available. But that doesn’t mean we should always be eating. In fact, going periods of time without food — such as with a 12 or 16 hour fast between dinner and our first meal the next day — can enhance anti-inflammatory mechanisms in the body including autophagy, your cell’s self-cleaning process that helps keep inflammation under control. If you’re interested in giving fasting a go, check out my complete guide to fasting here.

19. Watch your carbs.

When it comes to inflammation, carbohydrates — especially refined and processed breads, crackers, pastas, and baked goods — are one of the major culprits. If you want to fend off inflammation, following a ketogenic diet is a great place to start. Being in ketosis — which happens when your body starts using ketones for fuel instead of glucose, which it gets mostly from carbohydrates — has been shown (40) to be extremely helpful for brain health issues like autism, ADHD, bipolar disorder, schizophrenia, anxiety, and depression. Ketones are naturally anti-inflammatory; and coupled with their ability to cross the blood-brain barrier, reaching ketosis with a ketogenic diet can be a great way to further soothe inflammation. (41)

20. Eat eggs.

This incredible, edible superfood is one of the most unjustly and inaccurately persecuted foods ever! The yolk of the egg in particular gets a bad rap but forget everything you’ve heard about the evils of dietary cholesterol (which have all been disproven, by the way). Egg yolk contains the majority of the egg’s nutrients. All those well-intentioned people eating egg white omelets are missing out on some serious brain-boosting dietary power. The yolk is truly nature’s multivitamin, especially when it comes from organic, pastured eggs from chickens who roam outside in the sunlight.

One of the best nutrients for the brain is choline, (42) which has a variety of benefits for healthy brain function, including facilitating the synthesis of the neurotransmitter acetylcholine, and supporting cell-membrane signaling, which the entire hormonal system requires. Symptoms of choline deficiency include fatigue, insomnia, and memory problems, so eat more pastured egg yolks, which are also rich in omega-3 fats – another important healthy brain booster.

Keep in mind however, that as with all meat and dairy, not all eggs are created equal. Pasture-raised eggs have been shown to contain three times more of the brain beneficial omega-3 fats than supermarket eggs! Their nutritional superiority makes them totally worth a dollar or two more per dozen.

21. Try organ meats.

They may sound weird or unsavory, but organ meats are another real-food source of multivitamins. Throughout history, vigorous and healthy societies have traditionally consumed powerhouse superfoods like liver, but organ meats are now only eaten sparingly in modern Western society. Consider that the liver is a storage organ for many important brain nutrients like vitamins A, D, E, K, B12, and folic acid, as well as minerals such as copper and iron. Some people find liver pate a palatable way to get the nutritional benefits of organ meat without the yuck factor. Another interesting option is fermented cod liver oil, which comes in different forms like gels and capsules, if you want to take it in a whole-food supplement form. You can also find powdered organ meats in capsule form.

Healthy brain, healthy gut – the two are inextricably linked through nerve pathways (the gut-brain axis). And guess what has super gut-healing powers? Bone broth is one of the best foods you can consume for a healthy gut. This nutrient-rich liquid is filled with collagen, which acts like a healthy ointment to an inflamed gut, calming the burn and healing the lining.

23. Use coconut oil.

This amazing food contains the best possible fat for brain health: medium-chain triglycerides, or MCTs. A study (43) in the Journal of Neurobiology of Aging suggested that medium-chain triglycerides improved cognitive function among older folks with memory problems and Alzheimer’s disease, and coconut oil is one of the best sources. The amazing thing about this research was that cognitive function improved almost immediately following ingestion of the medium-chain triglycerides! Talk about fast-acting brain food.

24. Switch to grass-fed dairy.

I’ve said it before and I’ll say it again – fat is good for your brain, which is made up of 60% fat (44) and contains more cholesterol than any other organ in your body. Also, the cell membranes in the body, which carry messages between hormonal systems, are lined with these same components of saturated fat and cholesterol. That’s why it’s important to acquire these nutrients through your diet, and high-quality dairy is a good way to do that, if you tolerate dairy products.

Dairy should always be grass fed, organic, and preferably raw, for ultimate health benefits and minimum reactivity. Fermented dairy like kefir is also a good option. The healthy fats of grass-fed dairy are where all the brain food is, so avoid low-fat dairy products – they do not help you! The two primary fats that your brain wants and needs that grass-fed dairy has to offer are saturated fats and arachidonic acid. Another nutrient your brain craves is vitamin K2, which is critical for the formation of the myelin sheath and the nerves in the brain. We get this power nutrient from the fat of grass-fed animals, the very food that’s disappearing from our modern low-fat diet. It’s time to look to the past for a healthy future!

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