The People's Perspective on Medicine

Show 1002: How Bowel Bacteria Affect the Brain

The ecological relationships of our bowel bacteria have a profound impact on inflammation, which in turn affects many organ systems including the brain.
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How Bowel Bacteria Affect the Brain

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Until fairly recently, no one was really interested in the denizens of the digestive tract except for a few gastroenterologists and a few more microbiologists. But now research has shown that the bacteria in our bowels form complex ecological systems, and interest in the microbiome has gone mainstream.

Bowel Bacteria as a Source of Inflammation:

Inflammation is the driver behind many chronic conditions, including heart disease, diabetes, arthritis, psoriasis and others. But where is the inflammation coming from? Perhaps our standard American diet plays a role.

It turns out that we can influence the ecology of our microbiota by what we feed it. Find out what foods can help calm inflammation, and how this affects neurological conditions such as Alzheimer’s disease, autism or multiple sclerosis.

How exactly does the digestive tract talk to the brain? How do intestinal parasites affect that conversation? It is time to start paying attention to how our bowel bacteria affect brain function.

This Week’s Guest:

David Perlmutter, MD, FACN, ABIHM, is a board-certified neurologist and Fellow of the American College of Nutrition. He is an Associated Professor at the University of Miami Miller School of Medicine and the recipient of the Linus Pauling Award.

Dr. Perlmutter has written seven books, including The New York Times best-seller Grain Brain: The Surprising Truth about Wheat, Carbs and Sugar–Your Brain’s Silent Killers. His new book is Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain–for Life.

Listen to the Podcast:

The podcast of this program will be available the Monday after the broadcast date. The show can be streamed online from this site and podcasts can be downloaded for free for four weeks after the date of broadcast. After that time has passed, digital downloads are available for $2.99. CDs may be purchased at any time after broadcast for $9.99.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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incredibly thought provoking!

This Dr. has been on PBS lecturing about this same topic. Look up your Local PBS channel & Show Listings to possibly locate a Re-Run if you cannot obtain the People’s Pharmacy Pod Cast.

Once again information that informs our lives. Thank you

Thanks for airing this helpful broadcast. I am going to get Dr. Perlmutter’s book: Brainmaker.

I have a question. Dr. Perlmutter mentions Rush University’s nutritional epidemiologist Martha Clare Morris, PhD. I looked her up and I find that she and colleagues developed the “Mediterranean-DASH Intervention for Neurodegenerative Delay” (MIND) diet which is a hybrid of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diet. “A new diet, appropriately known by the acronym MIND, could significantly lower a person’s risk of developing Alzheimer’s disease, even if the diet is not meticulously followed, according to a paper published online for subscribers in March in the journal Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.”

Okay, that’s great, but I am surprised that the diet includes whole grains which to me is another word for gluten! Is anyone disappointed as I am that gluten seems to be a part of the MIND diet? For me and many I know, gluten causes a lot of inflammation that has a very negative effect on neuorological function. >”The MIND diet has 15 dietary components, including 10 “brain-healthy food groups” — green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil and wine — and five unhealthy groups that comprise red meats, butter and stick margarine, cheese, pastries and sweets, and fried or fast food.” Quotes are from the following article:

The MIND study seems like a great start. Not everyone is prepared to avoid all grains, nor does everyone need to. Not all grains contain gluten.

Dr. Perlmutter is quite clear on gluten, so we think you will find his book very helpful.

I have just been diagnosed with SIBO small intestine bacteria overgrowth, after suffering 2 years of chronic diarrhea. I am using a probiotic Saccharomyces Boulardii and XIFAXAN 550 mg and the problem has gone away. I have to avoid most vegetables including the potato family, many fruits and eat a low carb diet.
When I stop the antibiotic will my problem return?
Pat Roome

This was one of your finest shows, and I am fascinated by Dr. Perlmutter’s work. Ever since I read about the important work done by Dr. Candace Pert of Georgetown University–paired with research at the National Institutes of Health–in the 1990s, where it was found that there are more emotional receptors in the gut than in the brain, I realized this field is currently in a nascent stage and there is much more to learn. Dr. Pert’s book was written well over a decade ago and was called “Molecules of Emotion.” She asserted what Dr. Perlmutter told us: that most Serotonin receptors are in your gut. On some level, humans know this instinctively when we say things like “I have a gut feeling about this,” or that someone has “butterflies in their stomach.” The brain reacts to what is happening in the gut, not the other way around. Thank you for bringing Dr. Perlmutter on your show — this was very thought-provoking! I think the next step in this field is to fully identify the interactions between irritating, inflaming foods like gluten or High Fructose Corn Syrup and the types of intestinal bacteria that those foods encourage or discourage. Then we will fully understand why both diet and the gut flora are acting on our behalf, or acting against our good interests.

I really enjoyed your program featuring Dr. Perlmutter. I thought I might want to buy or make the kombucha tea that he recommends.

But then, the Mayo Clinic website says: “Proponents claim kombucha tea can stimulate the immune system, prevent cancer, and improve digestion and liver function. However, there’s no scientific evidence to support these health claims. There have, however, been reports of adverse effects, such as stomach upset, infections and allergic reactions in kombucha tea drinkers.

Kombucha tea is often brewed in homes under non-sterile conditions, making contamination likely. If ceramic pots are used for brewing, lead poisoning might be a concern — the acids in the tea may leach lead from the ceramic glaze.

In short, there isn’t good evidence that kombucha tea delivers on its health claims. At the same time, several cases of harm have been reported. Therefore, the prudent approach is to avoid kombucha tea until more definitive information is available.”

So who do I believe?

Anyway, thanks for a great program. I listen every week!

Thank you so much for bringing this to the attention of people who want to know about new and helpful research. For those who think it is a bunch of malarkey, remember when the conventional medical doctors thought germs and washing the hands was ridiculous and far out and continued to contaminate patients with disease and harmful bacteria. All those women who died after childbirth just because some doctor did not wash his hands.

Great show! Great topic for MUCH more research! Animals sometimes drink human urine, eat grass but did not know about humans drinking breast milk. PP topics for future?

Why not use breast milk to restore normal gut bacteria? This is how human’s naturally transfer it to the newborn. Is it the stigma of being too “personal”? Or the idea that it’s too sexually oriented for western medicine? It seems to me that it’s easier than fecal transplantation!

This was absolutely mindblowing and brings up so many questions. As a child growing up in war-time England where sweets were rationed, we would scrounge around in the fields and woods for stuff to eat. Nuts, fruits, berries and we even would dig up roots etc. taste them and if not bitter, eat them. We rarely washed our hands. I have been amazed that while surrounded by people with the flu, colds etc., I don’t get sick. So I believe that there is a lot of truth to Dr. Perlmutter’s theory.

I found this to be the most unintelligible show of all the fifteen years I have been listening. I am afraid to listen to listen to it again.

Great to bump into this conversation with the doc. I have been making and eating fermented vegetables for bout a year. I learned about this from Dr. Mercola. Mercola has also introduced me to Perlmutter via

I basically eat the same diet that Dr. Perlmutter mentioned at the end of the show to my surprise; including the chocolate. And I do fast. Amazing through out my day I rarely have cravings. I have listened to other conversations with Perlmutter and have plugged in that information to my personal research into health care.

I now say a happy stomach is a happy person!

Thanks to People’s Pharmacy and NPR to bring this information forthright.

Just finished listening to this interesting program. The gut microbiome is a deservedly hot topic in medicine. There is so much more to it than was discussed in this program, so I hope you will follow up with other speakers.

In my opinion, the most important discovery is the conversion of choline, phosphatidyl choline and carnitine to TMA (trimethylamine) by the gut bacteria. TMA is absorbed and converted to TMA-N-oxide (TMAO) by liver enzymes. TMAO inhibits reverse cholesterol transport and activates macrophages that damage arteries, leading to atherosclerosis in mice. Clinical studies show TMAO levels are strongly associated with higher rates of coronary heart disease outcomes in high risk patients. Type 2 diabetes may be affected by TMAO.

Choline, PC and carnitine are abundant in red meat, dairy and eggs. Thus TMAO provides a plausible mechanism to explain the observation that coronary heart disease and mortality are negatively associated with these dietary factors in some studies.

An excellent summary is “The Gut Microbial Endocrine Organ: Bacterially Derived Signals Driving Cardiometabolic Diseases” by Brown and Hazen in Annual Review of Medicine vol 66, p. 343, 2015.

The email ad for this entry in People’s Pharmacy has a short blurb concerning the bowel bacteria, which is a topic I would very much like to know more about. There is then a link to “READ MORE.” You click on it and it takes you to a page that has little or no information and a link to a podcast audio page. Listening is not reading! While a lot of subscribers will enjoy listening to the podcast, there are a good number who CANNOT listen to a podcast and would rather, or must, READ the article. People at work, at home where there are kids playing, people in environments where there are babies sleeping or sick patients or adults sleeping simply CANNOT listen to a podcast. The best solution would be to have a written transcription link for these people to select in addition to a link to the podcast for those who prefer audio. Please consider that many people are in situations where audio is not allowed or preferred for valid reasons.

Be sure to check out our “Listen and Read” offer of Dr. Perlmutter’s book together with a CD of the interview.

I wish I had heard some of this before I had my colon, pretty much voluntarily, completely removed for IBS,(I have a j pouch) My Dr. gives me very expensive probiotics, but they just make me gassy. I seem to have virtually no immune system –of course, without a colon, all those raw fruits and veggies I used to eat are sadly missed…anybody have any advice? Thanks

I am happy that you are providing information on this particular subject. It is much needed. I must have seen 15-20 local Gastroenterologist in the past 20 years and all have been interested only in a colonoscopy–that’s where the money is. If I had had colon cancer some 15 or 20 years ago, I would surely be dead by now. The many Gastro Doctors I have seen knew nothing of the connection between the gut and the brain and nothing about how the food we put into our gastro system affects our health. I have found some legitimate help from various sources, especially from the Gastro Clinic at UNC Hospital in Chapel Hill. I have kept my illness in check, mostly through diet and probiotics. I learned recently that there is such a thing as corn gluten. Thanks also for providing the Titles of books written by tomorrow’s speaker.

I have a condition called Bile Salts Malabsorption ~ a result of giving up my gall bladder. BSM brings on constant diarrhea and is a major problem for those of us who deal with it ~ actually they say about 20% of those who lose their gall bladder. I have dealt with this for 20 years. Among other things, I have found that a probiotic can be a partial help, and I take three a day from Do you think the probiotic raising my good bacteria, intestinally, helps with the bowel bacteria you are writing about?

Where’s the link to the podcast, please? New to this website, please provide instructions on how to find the podcast or radio show details.


Welcome to the site, Valerie! Many of our public radio stations will be airing the show tomorrow, August 8th. (We have the Air Date listed at the top of the page). The podcast will be available for download on Monday.

You can check to see if your local radio station is going to broadcast our show by checking our list here:

For more information about downloading our podcast, check out our information page here:

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