The Brain-Gut Highway: A Two-Way Street

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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:

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  • How Internal Organs Can Be Affected By Spicy Foods (Doctor Explains)

    10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.

    Capsaicin has an array of health-giving properties in moderation, but consumed in immoderation and/or without building up tolerance first, can cause problems—serious health issues such as heart attacks, brain spasms, torn esophagus, and even death can occur.

    Heating up

    Capsaicin, the compound that gives peppers their “heat”, is a chemical irritant and neurotoxin that activates pain receptors (TRPV1) tricking the brain into sensing heat, leading to a burning sensation, sweating, and flushing. The pain signal can also trigger the fight-or-flight response, causing a surge of adrenaline. Endorphins are eventually released, creating a pain-relief effect similar to a runner’s high, and ultimately it reduces systemic inflammation, boosts the metabolism, and increases healthy longevity.

    However, in cases of extreme consumption and/or lack of preparation, woe can befall, for example:

    • A man ruptured his esophagus after vomiting from eating a ghost pepper.
    • A participant experienced severe brain blood vessel constriction (reversible cerebral vasoconstriction syndrome) after eating a Carolina reaper.
    • A 25-year-old suffered permanent heart damage from cayenne pepper pills due to restricted blood flow.
    • A teenager died after the “one chip challenge,” although the cause of death was undetermined.

    So, what does moderation and preparation look like?

    Moderation can be different to different people, since genetics do play a part—some people have more TRPV1 receptors than other people. However, for all people (unless in case of having an allergy or similar), acclimatization is important, and a much bigger factor than genetics. 

    Writer’s anecdote: on the other hand, when my son was a toddler I once left the room and came back to find him cheerfully drinking hot sauce straight from the bottle, so it can be suspected that genetics are definitely relevant too, as while I did season his food and he did already enjoy curries and such, he didn’t exactly have a background of entering chili-eating competitions.

    Still, regardless of genes (unless you actually have a medical condition that disallows this), a person who regularly eats spicy food will develop an increasing tolerance for spicy food, and will get to enjoy the benefits without the risks, provided they don’t suddenly jump way past their point of tolerance.

    On which note, in this video you can also see what happens when Dr. Deshauer goes from biting a jalapeño (relatively low on the Scoville heat scale) to biting a Scotch bonnet pepper (about 10x higher on the Scoville heat scale):

    Click Here If The Embedded Video Doesn’t Load Automatically!

    Want to learn more?

    You might also like to read:

    Capsaicin For Weight Loss And Against Inflammation

    Take care!

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  • How To Manage Your Mood With Food (8 Ways)

    10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.

    It is hard to be mentally healthy for long without good diet. Food can not only affect our mood directly, but also indirectly because of how our brain works (or doesn’t, if we don’t have the right nutrients, or it is being sabotaged in some other dietary fashion).

    Selecting the food for setting the mood

    Mind, the mental health charity, have these advices to share (with some bonus notes of our own):

    1. Eat regularly: blood sugar peaks and troughs can heighten feelings of tiredness, irritability, or depression. Instead, enjoy foods that are high in energy but low in glycemic index, such as nuts, seeds, and oats—that way you’ll have plenty of energy, that lasts longer.
    2. Choose the right fats: omega-3 fatty acids are essential for the brain. So are omega-6 fatty acids, but it is rare to have a deficiency in omega-6, and indeed, many people have the ratio of omega-3 to omega-6 far too imbalanced in omega-6’s favor. So, focussing on getting more omega-3 fatty acids is important. Nuts and seeds are again great, as are avocados, eggs, and oily fish.
    3. Get a healthy amount of protein: and importantly, with a good mix of amino acids—so a variety of sources of protein is best. In particular, if you are vegan, paying attention to ensure you get a full spread of amino acids is critical, as not many plants have all the ones we need (soy does, though). The reason this is important for mood is because many of those amino acids double up as the building blocks of neurotransmitters, so they’re not entirely interchangeable.
    4. Stay hydrated: our bodies are famously made of mostly water, and our brain will not work well if it’s dehydrated. The human body can squeeze water out of almost anything that has water in it, but water from food (such as fruit, or soups) is best. If enjoying actual drinks, then herbal teas are excellent for hydration.
    5. Eat a rainbow of fruits and vegetables: these have many nutrients that are important for brain health, and the point of the colors is that most of those pigments are themselves nutrients. Additionally, the fiber content of fruits and vegetables is of topmost important for your heart, and as you’ll remember (we say it often, because it’s true): what’s good for your heart is good for your brain.
    6. Limit caffeine intake: for many people, excess caffeine can lead to feelings of anxiety, disrupt your sleep, and for everyone who has developed an addiction to it, it will cause withdrawal symptoms if stopped abruptly. Cutting back on caffeine, or even eliminating it, may improve your mood and sleep quality. Note, however, that if you have ADHD, then your brain’s physiological relationship with caffeine is a little different, and stimulants will be more beneficial (and less deleterious) for you than for most people. If unsure, speak with your doctor about this one.
    7. Support your gut health: because of the gut-brain axis (via the vagal nerve), and also because nearly all of our endogenous serotonin is made in the gut (along with other neurotransmitters/hormones), getting plenty of fiber is important, and probiotics can help too.
    8. Consider food intolerances: if you know you have one, then keep that in mind and tailor your diet accordingly. If you suspect you have one, seek a nutritionist’s help to find out for sure. These can affect many aspects of health, including mood, so should not be dismissed as a triviality.

    For more on all of this, enjoy:

    Click Here If The Embedded Video Doesn’t Load Automatically!

    Want to learn more?

    You might also like to read:

    The 6 Pillars Of Nutritional Psychiatry

    Take care!

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  • Could Just Two Hours Sleep Per Day Be Enough?

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    Polyphasic Sleep… Super-Schedule Or An Idea Best Put To Rest?

    What is it?

    Let’s start by defining some terms:

    • Monophasic sleep—sleeping in one “chunk” per day. For example, a good night’s “normal” sleep.
    • Biphasic sleep—sleeping in two “chunks” per day. Typically, a shorter night’s sleep, with a nap usually around the middle of the day / early afternoon.
    • Polyphasic sleep—sleeping in two or more “chunks per day”. Some people do this in order to have more hours awake per day, to do things. The idea is that sleeping this way is more efficient, and one can get enough rest in less time. The most popular schedules used are:
      • The Überman schedule—six evenly-spaced 20-minute naps, one every four hours, throughout the 24-hour day. The name is a semi-anglicized version of the German word Übermensch, “Superman”.
      • The Everyman schedule—a less extreme schedule, that has a three-hours “long sleep” during the night, and three evenly-spaced 20-minute naps during the day, for a total of 4 hours sleep.

    There are other schedules, but we’ll focus on the most popular ones here.

    Want to learn about the others? Visit: Polyphasic.Net (a website by and for polyphasic sleep enthusiasts)

    Some people have pointed to evidence that suggests humans are naturally polyphasic sleepers, and that it is only modern lifestyles that have forced us to be (mostly) monophasic.

    There is at least some evidence to suggest that when environmental light/dark conditions are changed (because of extreme seasonal variation at the poles, or, as in this case, because of artificial changes as part of a sleep science experiment), we adjust our sleeping patterns accordingly.

    The counterpoint, of course, is that perhaps when at the mercy of long days/nights at the poles, or no air-conditioning to deal with the heat of the day in the tropics, that perhaps we were forced to be polyphasic, and now, with modern technology and greater control, we are free to be monophasic.

    Either way, there are plenty of people who take up the practice of polyphasic sleep.

    Ok, But… Why?

    The main motivation for trying polyphasic sleep is simply to have more hours in the day! It’s exciting, the prospect of having 22 hours per day to be so productive and still have time over for leisure.

    A secondary motivation for trying polyphasic sleep is that when the brain is sleep-deprived, it will prioritize REM sleep. Here’s where the Überman schedule becomes perhaps most interesting:

    The six evenly-spaced naps of the Überman schedule are each 20 minutes long. This corresponds to the approximate length of a normal REM cycle.

    Consequently, when your head hits the pillow, you’ll immediately begin dreaming, and at the end of your dream, the alarm will go off.

    Waking up at the end of a dream, when one hasn’t yet entered a non-REM phase of sleep, will make you more likely to remember it. Similarly, going straight into REM sleep will make you more likely to be aware of it, thus, lucid dreaming.

    Read: Sleep fragmentation and lucid dreaming (actually a very interesting and informative lucid dreaming study even if you don’t want to take up polyphasic sleep)

    Six 20-minute lucid-dreaming sessions per day?! While awake for the other 22 hours?! That’s… 24 hours per day of wakefulness to use as you please! What sorcery is this?

    Hence, it has quite an understandable appeal.

    Next Question: Does it work?

    Can we get by without the other (non-REM) kinds of sleep?

    According to Überman cycle enthusiasts: Yes! The body and brain will adapt.

    According to sleep scientists: No! The non-REM slow-wave phases of sleep are essential

    Read: Adverse impact of polyphasic sleep patterns in humans—Report of the National Sleep Foundation sleep timing and variability consensus panel

    (if you want to know just how bad it is… the top-listed “similar article” is entitled “Suicidal Ideation”)

    But what about, for example, the Everman schedule? Three hours at night is enough for some non-REM sleep, right?

    It is, and so it’s not as quickly deleterious to the health as the Überman schedule. But, unless you are blessed with rare genes that allow you to operate comfortably on 4 hours per day (you’ll know already if that describes you, without having to run any experiment), it’s still bad.

    Adults typically need 7–9 hours of sleep per night, and if you don’t get it, you’ll accumulate a sleep debt. And, importantly:

    When you accumulate sleep debt, you are borrowing time at a very high rate of interest!

    And, at risk of laboring the metaphor, but this is important too:

    Not only will you have to pay it back soon (with interest), you will be hounded by the debt collection agents—decreased cognitive ability and decreased physical ability—until you pay up.

    In summary:

    • Polyphasic sleep is really very tempting
    • It will give you more hours per day (for a while)
    • It will give the promised lucid dreaming benefits (which is great until you start micronapping between naps, this is effectively a mini psychotic break from reality lasting split seconds each—can be deadly if behind the wheel of a car, for instance!)
    • It is unequivocally bad for the health and we do not recommend it

    Bottom line:

    Some of the claimed benefits are real, but are incredibly short-term, unsustainable, and come at a cost that’s far too high. We get why it’s tempting, but ultimately, it’s self-sabotage.

    (Sadly! We really wanted it to work, too…)

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  • Sesame & Peanut Tofu

    10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.

    Yesterday we learned how to elevate tofu from “nutrition” to “nutritious tasty snack” with our Basic Baked Tofu recipe; today we’re expanding on that, to take it from “nutritious tasty snack” to “very respectable meal”.

    You will need

    For the tofu:

    • The Basic Baked Tofu that we made yesterday (consider making this to be “step zero” of today’s recipe if you don’t already have a portion in the fridge)

    For the sauce:

    • ⅓ cup peanut butter, ideally with no added sugar or salt (if allergic to peanuts specifically, use almond butter; if allergic to nuts generally, use tahini)
    • ¼ bulb garlic, grated or crushed
    • 1 tbsp tamarind paste
    • 1½ tbsp tamari sauce (or low-sodium soy sauce, if a substitution is necessary)
    • 1 tbsp sambal oelek (or sriracha sauce, if a substitution is necessary)
    • 1 tsp ground coriander
    • 1 tsp ground black pepper
    • ½ tsp ground sweet cinnamon
    • ½ tsp MSG (or else omit; do not substitute with salt in this case unless you have a particular craving)
    • zest of 1 lime

    For the vegetables:

    • 14 oz broccolini / tenderstem broccoli, thick ends trimmed (failing that, any broccoli)
    • 6 oz shelled edamame
    • 1½ tsp toasted sesame oil

    For serving:

    • 4 cups cooked rice (we recommend our Tasty Versatile Rice recipe)
    • ½ cup raw cashews, soaked in hot water for at least 5 minutes and then drained (if allergic, substitute cooked chickpeas, rinsed and drained)
    • 1 tbsp toasted sesame seeds
    • 1 handful chopped cilantro, unless you have the “this tastes like soap” gene, in which case substitute chopped parsley

    Method

    (we suggest you read everything at least once before doing anything)

    1) Combine the sauce ingredients in a bowl and whisk well (or use a blender if you have one that’s comfortable with this relatively small quantity of ingredients). Taste it, and adjust the ingredient ratios if you’d like more saltiness, sweetness, sourness, spiciness, umami.

    2) Prepare a bowl with cold water and some ice. Steam the broccolini and edamame for about 3 minutes; as soon as they become tender, dump them into the ice bathe to halt the cooking process. Let them chill for a few minutes, then drain, dry, and toss in the sesame oil.

    3) Reheat the tofu if necessary (an air fryer is great for this), and then combine with half of the sauce in a bowl, tossing gently to coat well.

    4) Add a little extra water to the remaining sauce, enough to make it pourable, whisking to an even consistency.

    5) Assemble; do it per your preference, but we recommend the order: rice, vegetables, tofu, cashews, sauce, sesame seeds, herbs.

    Enjoy!

    Want to learn more?

    For those interested in some of the science of what we have going on today:

    Take care!

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  • Dr. Suzanne Steinbaum’s Heart Book – by Dr. Suzanne Steinbaum

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    The book is divided into three parts:

    1. What you should know
    2. What you should do
    3. All about you

    This is a very useful format, since it lays out all the foundational knowledge, before offering practical advice and “how to” explanations, before finally wrapping up with personalizing things.

    The latter is important, because while our basic risk factors can be assembled in a few lines of data (age, sex, race, genes, diet, exercise habits, etc) there’s a lot more to us than that, and oftentimes the data that doesn’t make the cut, makes the difference. Hormones on high on this list; we can say that a person is a 65-year-old woman and make a guess, but that’s all it is: a guess. Very few of us are the “average person” that statistical models represent accurately. And nor are social and psychological factors irrelevant; in fact often they are deciding factors!

    So, it’s important to be able to look at ourselves as the whole persons we are, or else we’ll get a heart-healthy protocol that works on paper but actually falls flat in application, because the mathematical model didn’t take into account that lately we have been very stressed about such-and-such a thing, and deeply anxious about so-and-so, and a hopefully short-term respiratory infection has reduced blood oxygen levels, and all these kinds of things need to be taken into account too, for an overall plan to work.

    The greatest strength of this book is that it attends to that.

    The style of the book is a little like a long sales pitch (when all that’s being sold, by the way, is the ideas the book is offering; she wants you to take her advice with enthusiasm), but there’s plenty of very good information all the way through, making it quite worth the read.

    Bottom line: if you’re a woman and/or love at least one woman, then you can benefit from this important book for understanding heart health that’s not the default.

    Click here to check out Dr. Suzanne Steinbaum’s Heart Book, and enjoy a heart-healthy life!

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  • What’s behind rising heart attack rates in younger adults

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    Deaths from heart attacks have been in decline for decades, thanks to improved diagnosis and treatments. But, among younger adults under 50 and those from communities that have been marginalized, the trend has reversed. 

    More young people have suffered heart attacks each year since the 2000s—and the reasons why aren’t always clear. 

    Here’s what you need to know about heart attack trends in younger adults.

    Heart attack deaths began declining in the 1980s

    Heart disease has been a leading cause of death in the United States for more than a century, but rates have declined for decades as diagnosis and treatments improved. In the 1950s, half of all Americans who had heart attacks died, compared to one in eight today. 

    A 2023 study found that heart attack deaths declined 4 percent a year between 1999 and 2020. 

    The downward trend plateaued in the 2000s as heart attacks in young adults rose

    In 2012, the decline in heart disease deaths in the U.S. began to slow. A 2018 study revealed that a growing number of younger adults were suffering heart attacks, with women more affected than men. Additionally, younger adults made up one-third of heart attack hospitalizations, with one in five heart attack patients being under 40.

    The following year, data showed that heart attack rates among adults under 40 had increased steadily since 2006. Even more troubling, young patients were just as likely to die from heart attacks as patients more than a decade older. 

    Why are more younger adults having heart attacks?

    Heart attacks have historically been viewed as a condition that primarily affects older adults. So, what has changed in recent decades that puts younger adults at higher risk? 

    Higher rates of obesity, diabetes, and high blood pressure

    Several leading risk factors for heart attacks are rising among younger adults.
    Between 2009 and 2020, diabetes and obesity rates increased in Americans ages 20 to 44. 

    During the same period, hypertension, or high blood pressure, rates did not improve in younger adults overall and worsened in young Hispanic people. Notably, young Black adults had hypertension rates nearly twice as high as the general population. 

    Hypertension significantly increases the risk of heart attack and cardiovascular death in young adults.

    Increased substance use

    Substance use of all kinds increases the risk of cardiovascular issues, including heart attacks. A recent study found that cardiovascular deaths associated with substance use increased by 4 percent annually between 1999 and 2019. 

    The rise in substance use-related deaths has accelerated since 2012 and was particularly pronounced among women, younger adults (25-39), American Indians and Alaska Natives, and those in rural areas.

    Alcohol was linked to 65 percent of the deaths, but stimulants (like methamphetamine) and cannabis were the substances associated with the greatest increase in cardiovascular deaths during the study period. 

    Poor mental health

    Depression and poor mental health have been linked to cardiovascular issues in young adults. A 2023 study of nearly 600,000 adults under 50 found that depression and self-reported poor mental health are a risk factor for heart disease, regardless of socioeconomic or other cardiovascular risk factors. 

    Adults under 50 years consistently report mental health conditions at around twice the rate of older adults. Additionally, U.S. depression rates have trended up and reached an all-time high in 2023, when 17.8 percent of adults reported having depression. 

    Depression rates are rising fastest among women, adults under 44, and Black and Hispanic populations. 

    COVID-19

    COVID-19 can cause real, lasting damage to the heart, increasing the risk of certain cardiovascular diseases for up to a year after infection. Vaccination reduces the risk of heart attack and other cardiovascular events caused by COVID-19 infection.

    The first year of the pandemic marked the largest single-year spike in heart-related deaths in five years, including a 14 percent increase in heart attacks. In the second year of the pandemic, heart attacks in young adults increased by 30 percent. 

    Heart attack prevention 

    Not every heart attack is preventable, but everyone can take steps to reduce their risks. The American Heart Association recommends managing health conditions that increase heart disease risk, including diabetes, obesity, and high blood pressure. 

    Lifestyle changes like improving diet, reducing substance use, and increasing physical activity can also help reduce heart attack risk. 

    For more information, talk to your health care provider.

    This article first appeared on Public Good News and is republished here under a Creative Commons license.

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