The Brain-Gut Highway: A Two-Way Street

Dr. Emeran Mayer, a gastroenterologist and neurologist, emphasizes the two-way interaction between the brain and gut. Managing stress and following a gut-friendly diet are crucial for gut health. However, for individuals with conditions like IBS, a personalized approach to the Mediterranean diet may be necessary.
The brain-gut highway

The Brain-Gut Two-Way Highway

This is Dr. Emeran Mayer. He has the rather niche dual specialty of being a gastroenterologist and a neurologist. He has published over 353 peer reviewed scientific articles, and he’s a professor in the Departments of Medicine, Physiology, and Psychiatry at UCLA. Much of his work has been pioneering medical research into gut-brain interactions.

We know the brain and gut are connected. What else does he want us to know?

First, that it is a two-way interaction. It’s about 90% “gut tells the brain things”, but it’s also 10% “brain tells the gut things”, and that 10% can make more like a 20% difference, if for example we look at the swing between “brain using that 10% communication to tell gut to do things worse” or “brain using that 10% communication to tell gut to do things better”, vs the midpoint null hypothesis of “what the gut would be doing with no direction from the brain”.

For example, if we are experiencing unmanaged chronic stress, that is going to tell our gut to do things that had an evolutionary advantage 20,000–200,000 years ago. Those things will not help us now. We do not need cortisol highs and adrenal dumping because we ate a piece of bread while stressed.

Read more (by Dr. Mayer): The Stress That Evolution Has Not Prepared Us For

With this in mind, if we want to look after our gut, then we can start before we even put anything in our mouths. Dr. Mayer recommends managing stress, anxiety, and depression from the head downwards as well as from the gut upwards.

Here’s what we at 10almonds have written previously on how to manage those things:

Do eat for gut health! Yes, even if…

Unsurprisingly, Dr. Mayer advocates for a gut-friendly, anti-inflammatory diet. We’ve written about these things before:

…but there’s just one problem:

For some people, such as with IBS, Crohn’s, and colitis, the Mediterranean diet that we (10almonds and Dr. Mayer) generally advocate for, is inaccessible. If you (if you have those conditions) eat as we describe, a combination of the fiber in many vegetables and the FODMAPs* in many fruits, will give you a very bad time indeed.

*Fermentable Oligo-, Di-, Monosaccharides And Polyols

Dr. Mayer has the answer to this riddle, and he’s not just guessing; he and his team did science to it. In a study with hundreds of participants, he measured what happened with adherence (or not) to the Mediterranean diet (or modified Mediterranean diet) (or not), in participants with IBS (or not).

The results and conclusions from that study included:

❝Among IBS participants, a higher consumption of fruits, vegetables, sugar, and butter was associated with a greater severity of IBS symptoms. Multivariate analysis identified several Mediterranean Diet foods to be associated with increased IBS symptoms.

A higher adherence to symptom-modified Mediterranean Diet was associated with a lower abundance of potentially harmful Faecalitalea, Streptococcus, and Intestinibacter, and higher abundance of potentially beneficial Holdemanella from the Firmicutes phylum.

A standard Mediterranean Diet was not associated with IBS symptom severity, although certain Mediterranean Diet foods were associated with increased IBS symptoms. Our study suggests that standard Mediterranean Diet may not be suitable for all patients with IBS and likely needs to be personalized in those with increased symptoms.❞

In graphical form:

And if you’d like to read more about this (along with more details on which specific foods to include or exclude to get these results), you can do so…

Want to know more?

Dr. Mayer offers many resources, including a blog, books, recipes, podcasts, and even a YouTube channel:

Share This Post

  • Is laziness a myth? Dr. Price dissects the true roots of “laziness” and offers practical solutions for overcoming exhaustion in work, projects, and personal relationships.

Learn To Grow

Sign up for weekly gardening tips, product reviews and discounts.

  • Stop Cancer 20 Years Ago

    Dr. Jenn Simmons shares vital tips on preventing cancer and inflammation, advocating for lifestyle changes and proactive health management at any age.

    Get Abreast And Keep Abreast

    This is Dr. Jenn Simmons. Her specialization is integrative oncology, as she—then a breast cancer surgeon—got breast cancer, decided the system wasn’t nearly as good from the patients’ side of things as from the doctors’ side, and took to educate herself, and now others, on how things can be better.

    What does she want us to know?

    Start now

    If you have breast cancer, the best time to start adjusting your lifestyle might be 20 years ago, but the second-best time is now. We realize our readers with breast cancer (or a history thereof) probably have indeed started already—all strength to you.

    What this means for those of us without breast cancer (or a history therof) is: start now

    Even if you don’t have a genetic risk factor, even if there’s no history of it in your family, there’s just no reason not to start now.

    Start what, you ask? Taking away its roots. And how?

    Inflammation as the root of cancer

    To oversimplify: cancer occurs because an accidentally immortal cell replicates and replicates and replicates and takes any nearby resources to keep on going. While science doesn’t know all the details of how this happens, it is a factor of genetic mutation (itself a normal process, without which evolution would be impossible), something which in turn is accelerated by damage to the DNA. The damage to the DNA? That occurs (often as not) as a result of cellular oxidation. Cellular oxidation is far from the only genotoxic thing out there, and a lot of non-food “this thing causes cancer” warnings are usually about other kinds of genotoxicity. But cellular oxidation is a big one, and it’s one that we can fight vigorously with our lifestyle.

    Because cellular oxidation and inflammation go hand-in-hand, reducing one tends to reduce the other. That’s why so often you’ll see in our Research Review Monday features, a line that goes something like:

    “and now for those things that usually come together: antioxidant, anti-inflammatory, anticancer, and anti-aging”

    So, fight inflammation now, and have a reduced risk of a lot of other woes later.

    See: How to Prevent (or Reduce) Inflammation

    Don’t settle for “normal”

    People are told, correctly but not always helpfully, such things as:

    • It’s normal to have less energy at your age
    • It’s normal to have a weaker immune system at your age
    • It’s normal to be at a higher risk of diabetes, heart disease, etc

    …and many more. And these things are true! But that doesn’t mean we have to settle for them.

    We can be all the way over on the healthy end of the distribution curve. We can do that!

    (so can everyone else, given sufficient opportunity and resources, because health is not a zero-sum game)

    If we’re going to get a cancer diagnosis, then our 60s are the decade where we’re most likely to get it. Earlier than that and the risk is extant but lower; later than that and technically the risk increases, but we probably got it already in our 60s.

    So, if we be younger than 60, then now’s a good time to prepare to hit the ground running when we get there. And if we missed that chance, then again, the second-best time is now:

    See: Focusing On Health In Our Sixties

    Fast to live

    Of course, anything can happen to anyone at any age (alas), but this is about the benefits of living a fasting lifestyle—that is to say, not just fasting for a 4-week health kick or something, but making it one’s “new normal” and just continuing it for life.

    This doesn’t mean “never eat”, of course, but it does mean “practice intermittent fasting, if you can”—something that Dr. Simmons strongly advocates.

    See: Intermittent Fasting: We Sort The Science From The Hype

    While this calls back to the previous “fight inflammation”, it deserves its own mention here as a very specific way of fighting it.

    It’s never too late

    All of the advices that go before a cancer diagnosis, continue to stand afterwards too. There is no point of “well, I already have cancer, so what’s the harm in…?”

    The harm in it after a diagnosis will be the same as the harm before. When it comes to lifestyle, preventing a cancer and preventing it from spreading are very much the same thing, which is also the same as shrinking it. Basically, if it’s anticancer, it’s anticancer, no matter whether it’s before, during, or after.

    Dr. Simmons has seen too many patients get a diagnosis, and place their lives squarely in the hands of doctors, when doctors can only do so much.

    Instead, Dr. Simmons recommends taking charge of your health as best you are able, today and onwards, no matter what. And that means two things:

    1. Knowing stuff
    2. Doing stuff

    So it becomes our responsibility (and our lifeline) to educate ourselves, and take action accordingly.

    Want to know more?

    We recently reviewed her book, and heartily recommend it:

    The Smart Woman’s Guide to Breast Cancer – by Dr. Jenn Simmons

    Enjoy!