How Your Gut Causes Brain Fog and How to Fix It

Brain fog is one of the most frustrating symptoms, and one I have dealt with personally.  Many people notice that when they improve their gut health, brain fog goes away.  Let’s discuss some recent research that shows why this happens and how this information can help you get better results with clearing brain fog.


Dr. Michael Ruscio, DC: Hi, this is Dr. Ruscio, and let’s discuss how your gut can contribute to brain fog and, more importantly, how healing your gut can help to fix brain fog. Brain fog can be a very unpleasant symptom. It’s something that I suffered with myself. It’s a feeling of feeling like you have slurred speech, like you can’t think, you can’t remember, you can’t speak clearly. Sometimes people can feel a little bit uncoordinated.

[Continue reading below]


DrMR: It’s a very, very unpleasant feeling. And the gut can contribute to brain fog. And improving the health of the gut can help with reversing that. But how does this all work? So one of the things that may happen—it was actually shown recently in a study that we’ll put up on the screen here.

It was shown that when patients underwent a low FODMAP diet, they actually saw an improvement in their brain fog. Now, what is a low FODMAP diet? And we’ll also put a link accompanying the transcript for this video for a low FODMAP diet guide. But essentially, a low FODMAP diet is a diet that restricts certain types of carbohydrates that feed bacterial growth.

How Your Gut Causes Brain Fog and How to Fix It - AdobeStock234087622WEBdietfodmapfoodAnd why this can be relevant is regarding something that we’ve talked much about, which is small intestinal bacterial overgrowth. High FODMAP foods can feed bacteria and worsen a condition known as SIBO, or small intestinal bacterial overgrowth. So, a low FODMAP diet can help starve these bacteria and help with this SIBO.

But how does this tie back into brain fog? Well, here is the interesting finding that brings us to this most recent study that showed that when putting a group of patients with IBS, gas, bloating, constipation, diarrhea, abdominal pain, on a low FODMAP diet, these patients actually saw an improvement in histamine, or a decrease in histamine.

Now, histamine is a compound that’s released by bacteria, and that can cause the feelings of brain fog. In fact, there are many patients that find relief from brain fog from going on a low histamine diet. And we’ll also put a link to a low histamine diet guide along with this transcript.

“So a low FODMAP diet starves the bacteria. Less bacteria, less histamine, less brain fog.”How Your Gut Causes Brain Fog and How to Fix It - tweet e1540485375388

Without getting too complicated, if you have digestive problems—gas, bloating, loose stools, constipation, diarrhea, abdominal pain, any of these—and you also have brain fog, then improving the health of your gut can be a great way to see your brain fog alleviated. And going on a low FODMAP diet can be a good step in that direction, because the low FODMAP diet does not provide a lot of food for bacteria. And if you have too much bacteria, those bacteria can release a lot of histamine. That histamine can cause brain fog.

How Your Gut Causes Brain Fog and How to Fix It - DrR Video Tiles Gut BrainSo a low FODMAP diet starves the bacteria. Less bacteria, less histamine, less brain fog. So if you’re suffering with brain fog and digestive symptoms, trying a healthy diet would be a great idea. There are many different types of healthy diets. A low FODMAP diet in this case, and especially a low FODMAP diet that’s of high-quality, non-processed foods as the food list we will provide is, then this may be a really great step toward balancing your gut to help heal your brain fog.

So this is a nice iteration of how the gut connects to the brain. So this is Dr. Ruscio, and I hope you find this helpful. Thanks.

What do you think? I would like to hear your thoughts or experience with this.

Dr. Ruscio is your leading functional and integrative doctor specializing in gut related disorders such as SIBO, leaky gut, Celiac, IBS and in thyroid disorders such as hypothyroid and hyperthyroid. For more information on how to become a patient, please contact our office. Serving the San Francisco bay area and distance patients via phone and Skype.

Discussion

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68 thoughts on “How Your Gut Causes Brain Fog and How to Fix It

      1. There are also histamine blocking supplements, not sure how well they work and they are expensive.
        I think Nutricology makes a pretty affordable version.

      1. There are also histamine blocking supplements, not sure how well they work and they are expensive.
        I think Nutricology makes a pretty affordable version.

  1. Have you found any studies that support the use of diatomacious earth, for both every day detoxification and for elimination of “bad” GI bugs/parasites?

  2. Have you found any studies that support the use of diatomacious earth, for both every day detoxification and for elimination of “bad” GI bugs/parasites?

  3. Does it make any sense to have SIBO and now be able to tolerate moderate and sometimes high FODMAP foods, but not be able to tolerate histamine foods at all now? Does that mean that the SIBO is still causing problems, just different problems now? I am at a loss on if I should keep treating SIBO or just try to heal my gut more and do the low histamine diet. Have had patients do a high dose antimicrobial SIBO protocol (like the Microb-X and Oil of Oregano) and get worse? I did that protocol and have more SIBO symptoms now….histamine issues and a bloating in my upper back, under left rib cage randomly sometimes. Any recommendations?

  4. Does it make any sense to have SIBO and now be able to tolerate moderate and sometimes high FODMAP foods, but not be able to tolerate histamine foods at all now? Does that mean that the SIBO is still causing problems, just different problems now? I am at a loss on if I should keep treating SIBO or just try to heal my gut more and do the low histamine diet. Have had patients do a high dose antimicrobial SIBO protocol (like the Microb-X and Oil of Oregano) and get worse? I did that protocol and have more SIBO symptoms now….histamine issues and a bloating in my upper back, under left rib cage randomly sometimes. Any recommendations?

  5. Brain fog…NOT a scientific name for what you describe. Whoever invented this word is not specific enough to be credited with setting the precedent for using it. I can think of lazy, fat, non-thinking kapha types who might be typified this way. I on the other hand have a rapid-fire brain which results in forgetting words and concepts as it has already moved on to the next topic. Given the loose and sketchy terminology, I would be said to be suffering from “brain fog”. I would suggest coming up with a different appelation to make it more clear and definitive. NOrmally you are more accurate in your choice of terms.

      1. I’m glad you said something because normally my brain can work.. He is not well versed In his opinion. Those that suffer brain for or cog fog would surely understand.Thanks for putting this out there. Because real!

  6. Great video, but I believe the more likely explanation of reduced histamine levels is reduced mast cell/(basophil?) activation(probably because of reduced fermentation in SI and better intestinal wall ingegrity). AFAIK, bacteria can produce histamine only by converting amino acid histidine. Unless we assume that low FODMAP diet drastically reduces bacterial numbers, or reduces protein intake(which doesn’t seem to be true), that explanation is unlikely, IMO. Although, we could speculate that bacteria go into hibernation due to low nutrient availability, and therefore stop converting histidine to histamine or that low FODMAP diet causes a change in microbiome and reduces histamine producing bacteria, favoring other species. Ok, I guess I just contradicted myself..:D

  7. Brain fog…NOT a scientific name for what you describe. Whoever invented this word is not specific enough to be credited with setting the precedent for using it. I can think of lazy, fat, non-thinking kapha types who might be typified this way. I on the other hand have a rapid-fire brain which results in forgetting words and concepts as it has already moved on to the next topic. Given the loose and sketchy terminology, I would be said to be suffering from “brain fog”. I would suggest coming up with a different appelation to make it more clear and definitive. NOrmally you are more accurate in your choice of terms.

      1. I’m glad you said something because normally my brain can work.. He is not well versed In his opinion. Those that suffer brain for or cog fog would surely understand.Thanks for putting this out there. Because real!

  8. Great video, but I believe the more likely explanation of reduced histamine levels is reduced mast cell/(basophil?) activation(probably because of reduced fermentation in SI and better intestinal wall ingegrity). AFAIK, bacteria can produce histamine only by converting amino acid histidine. Unless we assume that low FODMAP diet drastically reduces bacterial numbers, or reduces protein intake(which doesn’t seem to be true), that explanation is unlikely, IMO. Although, we could speculate that bacteria go into hibernation due to low nutrient availability, and therefore stop converting histidine to histamine or that low FODMAP diet causes a change in microbiome and reduces histamine producing bacteria, favoring other species. Ok, I guess I just contradicted myself..:D

  9. How do you navigate a world in which low-oxalate, low-lectin and low-fodmap diets all exist? So many of the symptoms requiring any of these three diets overlap so much, is breath-testing really the only way to decide which to start first for such symptoms as bloating, gas, diarrhea or constipation plus chronic pain or allergy symptoms, and maybe also brain fog?

  10. Hello Dr.Ruscio,
    Starving the bacterial is one thing but even if it does tone down symptoms is it really a permanent fix? I mean those bacteria won’t die – at best they’ll just wait but at worst (the theory I’ve personally experience) they’ll get ‘angry’ and make symptoms worse. Isn’t there any targeted drug or fool-proof method for sterilising the small intestine? I have severe SIBO cause terrible brain fog.
    Sincerely,
    Sam

    1. A protocol I’ve read about recently, (not sure if it works but it makes sense) would be to go on a 14 day antibiotic regiment and an anti-parasitic protocol for a month but then start to supplement a good probiotic right after the antibiotic treatment. The idea is to kill all good and bad bacteria and then supplement the good bacteria back-in manually to make sure they are rooted prior to any bad bacteria overgrowth. The antibiotic will kill systemic bacteria; stomach, small intestine (SIBO) and large intestine. I don’t have the link to this information but you can use a search engine to find articles related to SIBO eradication.

      1. So I am led to believe antibiotics pass through the smallnintestine too quickly and are not effective in destroying bacteria good or bad. I have heard of a new antibiotic that has been developed in England by a team of professors who specialise in the bowel. One of them I believe is professor Peter Whorewell of Manchester university hospital. He has written books and is considered by many to me a world expert on irritable bowel and things like SIBO. He is the head of the UKs NHS national health service only bowel centre which offers hypnotherapy to some 2000 patients per year and obviously as it’s the NHS is free. I believe they can also offer treatment via Skype as some people just can’t leave their homes. Hypnotherapy is worth looking into but can be expensive if going privately costing anything from 80 to 120 per session and taking 12 sessions or more and may not even work for you. This new antibiotic developed is supposed to stay in the small intestine so it can work in the small intestine and therefore is supposed to be excellent for SIBO. I am sorry but forget the name of it but I am sure if you Google “new anti biotic for SIBO or small intestine” then it should come up

  11. Hello Dr.Ruscio,
    Starving the bacterial is one thing but even if it does tone down symptoms is it really a permanent fix? I mean those bacteria won’t die – at best they’ll just wait but at worst (the theory I’ve personally experience) they’ll get ‘angry’ and make symptoms worse. Isn’t there any targeted drug or fool-proof method for sterilising the small intestine? I have severe SIBO cause terrible brain fog.
    Sincerely,
    Sam

    1. A protocol I’ve read about recently, (not sure if it works but it makes sense) would be to go on a 14 day antibiotic regiment and an anti-parasitic protocol for a month but then start to supplement a good probiotic right after the antibiotic treatment. The idea is to kill all good and bad bacteria and then supplement the good bacteria back-in manually to make sure they are rooted prior to any bad bacteria overgrowth. The antibiotic will kill systemic bacteria; stomach, small intestine (SIBO) and large intestine. I don’t have the link to this information but you can use a search engine to find articles related to SIBO eradication.

      1. So I am led to believe antibiotics pass through the smallnintestine too quickly and are not effective in destroying bacteria good or bad. I have heard of a new antibiotic that has been developed in England by a team of professors who specialise in the bowel. One of them I believe is professor Peter Whorewell of Manchester university hospital. He has written books and is considered by many to me a world expert on irritable bowel and things like SIBO. He is the head of the UKs NHS national health service only bowel centre which offers hypnotherapy to some 2000 patients per year and obviously as it’s the NHS is free. I believe they can also offer treatment via Skype as some people just can’t leave their homes. Hypnotherapy is worth looking into but can be expensive if going privately costing anything from 80 to 120 per session and taking 12 sessions or more and may not even work for you. This new antibiotic developed is supposed to stay in the small intestine so it can work in the small intestine and therefore is supposed to be excellent for SIBO. I am sorry but forget the name of it but I am sure if you Google “new anti biotic for SIBO or small intestine” then it should come up

  12. I had severe histamine intolerance that became extreme for 3 years during seasonal allergy season. I no longer sneeze etc. but weakness and Brain fog were a constant. The enzyme in that gut that controls histamine is not found in the brain. The precursor to the enzyme in the brain that nukes histamine, is Sam-e which I started taking before allergy season, as well as using white onions on recommendation from a friend. This past summer waa the best allergy season I have had since I was a child.

  13. I had severe histamine intolerance that became extreme for 3 years during seasonal allergy season. I no longer sneeze etc. but weakness and Brain fog were a constant. The enzyme in that gut that controls histamine is not found in the brain. The precursor to the enzyme in the brain that nukes histamine, is Sam-e which I started taking before allergy season, as well as using white onions on recommendation from a friend. This past summer waa the best allergy season I have had since I was a child.

  14. Dr Rouscio you are one the finest doctor i have seen in my life the way you explained this problem splendid one i am suffering from IBS due to which i have very terrific experience of brain fog i need good plan diet through which could be able to get rid from this plz help me i am taking Librax tablet for IBS but some time it works & sometime it doesn’t how can i make my gut healthy plzz suggest me

  15. Dr Rouscio you are one the finest doctor i have seen in my life the way you explained this problem splendid one i am suffering from IBS due to which i have very terrific experience of brain fog i need good plan diet through which could be able to get rid from this plz help me i am taking Librax tablet for IBS but some time it works & sometime it doesn’t how can i make my gut healthy plzz suggest me

  16. Can you help me in 18 dealing with brain fog I don’t really use the bathroom and doctors say everything is fine PLEASE

  17. Thank you, Dr. R! This is , by far, one of the most informative and clear-cut explanations relating to gut concerns I’ve read so far.. I’m suffering tremendously from brain fog- so much so that I cannot see straight!

    What are your thoughts on the most effective strains of probiotics to heal high histamine, leaky gut, SIBO, etc?

    Thank you in advance.

  18. Thank you, Dr. R! This is , by far, one of the most informative and clear-cut explanations relating to gut concerns I’ve read so far.. I’m suffering tremendously from brain fog- so much so that I cannot see straight!

    What are your thoughts on the most effective strains of probiotics to heal high histamine, leaky gut, SIBO, etc?

    Thank you in advance.

  19. Hello, sir your article was really nice and finally something I could relate to .
    I would like to share my problem and ask your opinion over this . I am a high school student and my exams are near , some days back I probably ate something bad and since then I have not been able to use my brain properly . I don’t even think about anything negative and still my stress levels are always high , and I am on a high heartbeat . I don’t exactly know what the reason is but it has been bothering me for some days now . My exams are near and I need to get to my normal state as soon as possible , please help me solve my problem . Thanks !!!

    1. Hi there,

      I’m sorry to hear you’re not feeling well. You could try the low FODMAP diet as suggested in the video above, and if that doesn’t work, I’d suggest picking up a copy of Dr Ruscio’s book “Healthy Gut, Healthy You” as it walks through a DIY protocol to help solve tough digestive issues. You can find it here: https://www.drruscio.com/getgutbook Good luck!

  20. Hello, sir your article was really nice and finally something I could relate to .
    I would like to share my problem and ask your opinion over this . I am a high school student and my exams are near , some days back I probably ate something bad and since then I have not been able to use my brain properly . I don’t even think about anything negative and still my stress levels are always high , and I am on a high heartbeat . I don’t exactly know what the reason is but it has been bothering me for some days now . My exams are near and I need to get to my normal state as soon as possible , please help me solve my problem . Thanks !!!

    1. Hi there,

      I’m sorry to hear you’re not feeling well. You could try the low FODMAP diet as suggested in the video above, and if that doesn’t work, I’d suggest picking up a copy of Dr Ruscio’s book “Healthy Gut, Healthy You” as it walks through a DIY protocol to help solve tough digestive issues. You can find it here: https://www.drruscio.com/getgutbook Good luck!

  21. Thanks so much for this Dr. Ruscio!
    I just looked up the study you referenced on low FODMAP and brain fog and don’t see a reference to brain fog in the study abstract. I am sure I am missing something but do you mind explaining how you came to this conclusion?

    Thank you!
    Heather Woodruff, cnp

    1. Hi Heather,

      The missing piece there is histamine. Low FODMAP diet led to an eightfold decrease in histamine and high histamine levels are known to cause brain fog.

      To keep the video simple, he omitted this detail. Also, IBS is linked to fatigue and when patients see improved IBS, they have less fatigue. Some brain fog, in Dr Ruscio’s experience, is a byproduct of fatigue.

      Hope this helps!

  22. Thanks so much for this Dr. Ruscio!
    I just looked up the study you referenced on low FODMAP and brain fog and don’t see a reference to brain fog in the study abstract. I am sure I am missing something but do you mind explaining how you came to this conclusion?

    Thank you!
    Heather Woodruff, cnp

    1. Hi Heather,

      The missing piece there is histamine. Low FODMAP diet led to an eightfold decrease in histamine and high histamine levels are known to cause brain fog.

      To keep the video simple, he omitted this detail. Also, IBS is linked to fatigue and when patients see improved IBS, they have less fatigue. Some brain fog, in Dr Ruscio’s experience, is a byproduct of fatigue.

      Hope this helps!

  23. What do you do if you have been on the Low Fodmap diet (following strictly), are taking HCL with every meal, spacing meals out, and also on a prokinetic, and you STILL have brain fog? Been treated for SIBO many times and last breath test was negative.

    Thanks

      1. Hi Anna,

        Did you ever try a low histamine diet? Sometimes brain fog can be a symptom of histamine intolerance.

        Aside from that, my two suggestions would be:

        1) Check out Dr Ruscio’s book “Healthy Gut, Healthy You”. While you may have treated gut issues in the past, it’s possible that the treatment wasn’t comprehensive enough, or didn’t layer in synergistic treatments like Dr Ruscio outlines in the book. You can find it here: https://www.drruscio.com/getgutbook

        2) Consider that your brain fog may not be caused by gut issues and talk to your doctor about other possible root causes (stress, lack of sleep, hormone imbalances, lyme/co-infections, mold, etc)

        Hope this helps!

  24. What do you do if you have been on the Low Fodmap diet (following strictly), are taking HCL with every meal, spacing meals out, and also on a prokinetic, and you STILL have brain fog? Been treated for SIBO many times and last breath test was negative.

    Thanks

      1. Hi Anna,

        Did you ever try a low histamine diet? Sometimes brain fog can be a symptom of histamine intolerance.

        Aside from that, my two suggestions would be:

        1) Check out Dr Ruscio’s book “Healthy Gut, Healthy You”. While you may have treated gut issues in the past, it’s possible that the treatment wasn’t comprehensive enough, or didn’t layer in synergistic treatments like Dr Ruscio outlines in the book. You can find it here: https://www.drruscio.com/getgutbook

        2) Consider that your brain fog may not be caused by gut issues and talk to your doctor about other possible root causes (stress, lack of sleep, hormone imbalances, lyme/co-infections, mold, etc)

        Hope this helps!

  25. How do you navigate a world in which low-oxalate, low-lectin and low-fodmap diets all exist? So many of the symptoms requiring any of these three diets overlap so much, is breath-testing really the only way to decide which to start first for such symptoms as bloating, gas, diarrhea or constipation plus chronic pain or allergy symptoms, and maybe also brain fog?

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