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Category: Brain Maker

How Gut Bacteria Protect The Brain

The blood-brain barrier (BBB) acts as a gatekeeper, protecting the brain from various toxic elements while allowing the entrance of various life-sustaining nutrients like water, glucose, amino acids, and gases that are essential for the function of the brain. It is formed by cells that line the capillaries and are connected by what are called “tight junctions,” quite similar to the tight junctions in the cells that line the gut.

Any number of brain disorders is associated with breakdown of the BBB including infections, and even cancer. And as such, scientists have aggressively studied the BBB to determine specifically what leads to increased permeability and, perhaps most importantly, what can be done to reduce permeability in other words what can be done to reestablish the barrier, and protect the brain.

In a stunning new research report appearing in the journal, Science Translational Medicine, researchers at the Karolinska Institute in Stockholm studied the blood brain barrier in mice that were “germ free.” That means, that the mice used in this experiment did not have bacteria living within their intestines. Using highly sophisticated brain scanning technology, the researchers demonstrated that the blood brain barrier in these mice was significantly compromised, basically a situation of what we may call a “leaky brain,” and this leakiness of the barrier persisted into adulthood.

Even more compelling was their finding that when these mice received a fecal transfer, meaning that their intestines were inoculated with the fecal material including bacteria from a healthy mouse, the permeability of the blood brain barrier was markedly improved.

First, this research is groundbreaking. The implications of being able to manipulate the health of the blood brain barrier by making changes in the gut bacteria offers up for the first time a powerful therapeutic tool that may have incredibly wide application in brain disorders. Professor Sven Pettersson, the principal investigator involved in the study was quoted in Science Daily as stating:

Given that the microbiome composition and diversity change over time, it is tempting to speculate that the blood-brain barrier integrity also may fluctuate depending on the microbiome. This knowledge may be used to develop new ways for opening the blood-brain-barrier to increase the efficacy of the brain cancer drugs and for the design of treatment regimes that strengthens the integrity of the blood-brain barrier.

Second, this research adds further evidence to the notion that a wide array of human health issues may well depend upon the diversity and complexity of the array of bacteria that lives within the gut, known as our microbiome.

It is very humbling to consider that what seems to be emerging as our most powerful leverage point in terms of treating a variety of disease states may well rest in the hands of the hundred trillion bacteria that consider our bodies to be their home. These are the fundamentals of a new horizon in medicine that are explored in my new book, Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain–for Life.

Finally, in closing, let me state that I fully appreciate that conceptually, my blog postings are clearly becoming a bit more complex in terms of the subjects I am exploring. My mission is to do my very best to make this information understandable, and bring to your attention the health-related relevance of these new scientific discoveries.


  • Rick

    What type or brand of probiotics do you recommend?

    • David Perlmutter

      One option is my Empowering Probiotic: store.drperlmutter.com/collections/individual-supplements/empowering-probiotic

      • Liz

        nothing at that link Dr..

      • Angela Milne

        Thanks, do you know of any good products in South Africa?

      • Ri

        Doc im a huge fan of coffee and you say drink up! but i also respect Dr Perricone’s work in the field of health and nutrition especially how it pertains to skin care and he says dont drink coffee because it elevates cortisol levels and insulin levels and causes weight gain so switch to green tea-can you explain this?

        • opinions on coffee consumption are varied. many well designed studies say that healthy humans can benefit by moderately consuming coffee (black, unsweetened).

          but if one is obese, and consumes oiled coffee, much worse, latees with a lot of milk and sugar…of course you may see hormonal dis-regulation and health issues…

          one cannot and should not generalize that: “coffee is bad, don’t drink it!”. context matters folks.

          • ri

            thanks Chris but that still doesnt answer my question lol!im thin and i drink coffee daily i wouldnt mind losing a few pounds though and more than that health is at the forefront of my mind. I wont stop drinking coffee because i love it and i dont add sugar just cream

  • LindaR

    WOW! Fascinating and hope inspiring research!

  • Arturo Cortes

    Dr Permutter, Thanks for sharing this information with people, how ever I’m trying since last year to get an appointment with you for my son Felipe Cortes age 11. Could you please see if he’s able see you Asap he really needs to be seen by you. (Petite mal) Thanks a lot!

    • Billy

      How about kefir water???

  • tpagen

    Do you think it is better to try and get the bacteria with natural products like kefir, yogurt, kumbucha and fermented vegetables instead of a supplement pill? What are your thoughts about consuming resistant starch (unmodified potato starch) when you eat low carb to make sure there is enough food for your gut biome?

    • TechnoTriticale

      > … get the bacteria with natural products …

      Or get them the ancestral way, from dirt (potential hazards there).

      The problems with foods as a sources of probiotics (the bugs) are:
      1. They may all be dead (and will be with pasteurized products).
      2. Too few colony forming units (CFUs).
      3. Suboptimal spectrum of species.

      Quality commercial probiotics are a more consistent choice. And “quality” excludes most of the products on room-temperature retail store shelves, where we see the laughable disclaimer “at time of manufacture” for viable CFU counts.

      Expect knowledge and products to evolve rapidly, and perhaps in surprising directions, on this topic over the next few years.

      • Liz

        So perhaps a prebiotic is better than..since that would feed your gut bacteria?

        • TechnoTriticale

          re: So perhaps a prebiotic is better than..since that would feed your gut bacteria?

          You need both, and most people are deficient in both. Probiotics are the critters. Prebiotic fibers are the critter food.

          An initial course of probiotics may suffice, with a periodic refresher (esp. during and after any antibiotics), but the prebiotic fiber you need every day, or your critter farm may collapse, and your health benefits with it.

      • Emmalee

        I take a product that is considered more of a probiotic food vs. supplement. VSL#3. Always refrigerated. Have taken for years and it helps a great deal with all my GI issues.

      • Janine Roberts

        Probiotics worked temporarily for my daughter, but as soon as I stopped giving them at massive doses, everything turned back to her natural state. After having her faeces tested, it seems there are bacteria which inhibit other bacteria growth by toxins. Looks like we are heading down the foecal transplant road as I believe that it really has a strong effect on her brain.

      • Mihaela

        This is not quite true. Kefir from organic raw cow/goat milk contains approx 150 billion CFU per spoon, it is better than MOST of the products on the market. Fermented vegetables are also great if made correctly, just with salt or a starter like kefir/whey, without adding boiled water cause it would kill the good bacteria.

  • Angela Milne

    Maybe we can just transfer the bacteria, not the poop 😉

    • David Perlmutter

      That’s what it boils down to Angela. The name can certainly be a bit misleading!

      • Angela Milne


  • Traci Wagner Griggs

    Great job explaining about the importance of gut bacteria. Our guts really are related to our overall health-from our head to our toes, as well as from the inside out!

    • David Perlmutter

      Thank you Traci. It’s an important subject for sure, and central to Brain Maker.

      • Ri

        when i started having issues with my allegic reactions(breaking out in hives from head to toe and swollen lips and eyelids) that occurred for the first time in 29 years (happened on two different occassions last year) i dug deep and did some research because all the doctors had no explanation for this idiopathic uticaria. It was beyond frustrating! i turned to a homeopathic doctor who gave me some of his expensive medicine-bella donna and another one i forget the name but he also told me it was an autoimmune disease allergy type because it was a delayed reaction.So i started on a good probiotic and upped my intake of vitamind d3 and also completely cut out gluten and dairy since he said based on my blood type i had food sensitivities to both..Upon further reseach i realized that my reactions were directly correlated to leaky gut! it was a breakthrough ! all i needed to do was treat my leaky gut. I since havent had a breakout Thank God! i cant wait for Dr Perlmutter’s new book ill be ordering it on my Kindle! His amazing research and findings are life changing. I Feel like i have an edge in life because im shooting for optimal health and with Dr Perlmutter’s books i know i can get there!

      • Arben

        I wish to think deeply Dr. David Perlmutter. Thanks to Your brillant book Grain Brain I could change the health of my son, cutting off bread, pasta, sugar and starting with a whole new way of dieting. I follow you so eagerly all your articles and posts. You are giving a great hepl to humanity. From Tirana, Albania, Europe. Arben
        This, too, was a great article abour germs, guts and BBB. So doing. You gave me a new way of watching human being as compound by millions tiny creatures who live inside us. So, I think that the very being are not US, mankind, but the very ruler are the bacterias.

  • Plants with pesco

    The anti-bacterial properties of turmeric may be an important key to Okinawans and residents of Ballagbarth, India low rates of dementia, Alzheimer’s and mood disorders. It is likely turmeric’s anti-inflammatory, antioxidant and antibacterial properties (eliminating bad bacteria like h. pylori etc…) all have an impact and, turmeric’s ability to balance the micro biome may be the the most important factor- who knows?

    Both groups also ate a variety of prebiotic foods: onions, greens, chickpeas or soybeans (tofu, soy sauce, miso…), sweet potatoes, sushi (cooked and cooled rice), shiitake, maitake and reishi mushrooms and rice.

    It is exciting to see all the wonderful new, research on the gut-brain connection and, hopefully doctors will look to prescribe fermented foods, probiotics, dietary change (i.e. elimination diet) and stress relievers, such as exercise, sleep, therapy, and meditation first for patients with mild mood disorders, symptoms of early dementia and for people suffering with gastrointestinal disorders. The gut-brain connection may be so strong that they may need to the think of the gut and brain as one organ, constantly working reciprocally.

    • Labra

      How much tumeric would be good per day.(I have powder).

      • David Perlmutter

        Think 350mg 2x/day. drperlmutter.com/grain-brain-seven-super-supplements/

  • Ingrid Sweden

    Thank you for sharing Dr Perlmutter! You’re doing such a wonderful job educating people and encuraging us to take charge of our own health. Just want to send you some appreciation from Sweden! Do you think this could open up for new treatments in autism etc.? My 3 year old twin nephews have recently been diagnosed with it, which of course has made us very sad but also determined to do everything to help them, even improve their abilities. Again, thank you so much for doing what you can to help people in desperate need!

    • lisa scott

      Angela…Read Dr Natasha Campbell-McBride, MD : GAPS Gut and Psychology Syndrome treatment ror autism among other disorders…She is a parent who ‘cured’ her son


    Keep it coming-I really look forward to all of your posts and the wonderful information you choose to share-you are a neuro-rock star!

    • David Perlmutter

      Will keep sharing as long as you keep reading.

  • GemmaStar

    I can hardly wait for BRAIN MAKER to come out. I’ve relished GRAIN BRAIN (and given copies to friends) and I know I’m going to feel the same way about MAKER.

    But while I wait for Dr. Perlmutter’s new book, I’ve started making my own kefir (really easy), kimchi (easy but takes a bit of time — all that chopping), sauerkraut (I use the shredding blade so it’s pretty fast and easy to prepare). I’ve also started making my own kombucha. Delicious!

    It isn’t difficult to make these things. I’m a newbie and between the Internet, YouTube and my own reading, I’m making progress. Two good sources for information on culturing and fermenting are:



    • David Perlmutter

      Fermented foods are so important Gemma, good to see you not only working them into your diet, but making them yourself!

  • Charry

    The more complexity, the more technical, the better. Bring it on!

  • Ignaz

    Chlorinated Water and Vaccine Excipients/Preservatives.

    Does anyone have any evidence that chlorine in drinking water (designed to kill pathogenic microbes) kills beneficial gut bacteria?

    Similarly, is there anything around which demonstrates that vaccine ingredients can cause gut dysbiosis?

  • coolmutha berta

    . . . should read “their home,” not “there home” in second-to-last paragraph

    • David Perlmutter

      You’re correct! Will change that.

  • Jean

    Do we need to be concerned that chances are the probiotic supplements are not refrigerated when they are shipped?

  • Jean yves Let

    Thank you for sharing your work and your so valuable advices. A question about APOE: what conclusions drawn from the data published on the website below, especially regarding the recommendations?
    Thanking you
    Jean yves Let

  • Eve-Loraine

    If I am eating 20g carb, what to I need to feed my gut colony?

  • Eve-Loraine

    If I eat resistant starch e.g. Green banana, cold potato, how do I count the carbs?

    • David Perlmutter

      You’ll want to count the total carbs there.

  • Leaky gut, leaky brain. An immensely important topic!

    • David Perlmutter


  • becki

    Two questions Dr.Perlmutter please:
    1. I have RA and have gut problems, am eating LCHF as of 1/1/15 and my gut it mucher better. I am insulin resistant and have a sensitivity to wheat by LCAT blood work. Do I need probiotics and if I do, what do I buy?
    2. I do have your book and love it. What about grains causing vascular dementia?

  • Light444

    Very exciting implications and possibilities!!

  • BJ

    My husband and I have followed your plan for over a year. Three years ago he was having symptoms of Alzheimer’s but they pretty much stopped. Recently after being ill he developed symptoms again and has been diagnosed with early Alzheimer’s. They want him to take Aricept but I am concerned about side effects, particularly gastrointestinal. Is it advisable for him to take Aricept or continue dealing with it through nutrition and exercise?

  • Peter

    Mission accomplished…exponentially!

  • Teri H

    Perhaps this is some insight into the “reason why” of the two primary cancers that attacked my mom….. lymphoma in the gut AND brain cancer. Thank you.

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  • Dr Perlmutter, have you seen any of your patients with sensory processing disorders helped with eliminating grains and adding probiotics to the diet? My son has been diagnosed with visual and auditory processing disorders. We will be beginning Visual Therapy soon.

  • Susan

    Wonderful information! I write the article about brain and protecting it for my Premier Essay and this post was very useful for me. Indeed, the brain – the foundation of our health and long life. We must be very attentive to its signals.

  • Jan Red

    Yes, more complex, but riveting nonetheless!

  • Emily Matthews

    GAPS protocol works, see http://www.gaps.me

  • I think this study supports these ideas – http://www.scientificamerican.com/article/artificial-sweeteners-may-change-our-gut-bacteria-in-dangerous-ways/?WT.mc_id=SA_Facebook

    And interestingly. the use of antidepressants may also be related to the use of artificial-sweeteners as well? It’s an interesting idea. We are indeed what we eat.

    • Marion Sampson

      Chemical, man-made sugars are used in all medications, vaccines, processed foods, drinks, etc. unless specified otherwise on the package.
      Has anyone read Dr. Russell Blaylock’s (neurosurgeon) articles, one in particular is the forward to Neil Z. Miller’s publication, the Vaccine Safety Manual. The flu shot is a sham. They are putting diseases into us for a lifetime that they will “treat” or “manage”. with drugs. Our wonderful doctors/pediatricians and nurses don’t know what is in those vaccines but they have to push them; it’s their mandate and they get perks or threats; pick one. God help our children. The advertising for all of this is in their faces wherever they go.

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  • denisO

    Good information. Speaking of leaky brains, have you written anything about leaky gut walls, and bacteria permeating into the blood stream? This article claims excessive exercise can cause it:


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  • Derrek

    What supplements do you recommend to heal the blood brain barrier? I can’t find much information online and can’t find a doctor.

  • In 2015, researchers in Australia, demonstrated that temporarily breaking down the BBB with IV microbubbles and scanning ulstrasound increased microglial clearance of amyloid beta (and memory performance!) in a mouse model of Alzheimers. http://stm.sciencemag.org/content/7/278/278ra33

    My question, Dr P is: Do we see (or expect) an association with dysbiosis, leaky gut and *DECREASED* incidence or severity of Alzheimers? We know that leaky-gut and GI inflammation is generally not good, but is there a side benefit in AD?

  • Marion Sampson

    Polysorbate in ice cream, cottage cheese, vaccines, etc. causes the BBB to be penetrated. That is criminal and the makers of it know the damages it causes. If not, they can’t call themselves scientists and the FDA needs to hire some real scientists. The vaccine protocol has increased to a point that is criminal, the brains of our little children are violently stimulated and toxic.

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