When Hippocrates, the ancient Greek father of medicine, said, “All disease begins in the gut,” he was probably right. We now know that poor gut health is linked to a broad range of diseases and health conditions, from depression to diabetes, cancer to obesity, and autism to autoimmune disease. Researchers are even exploring the connection between gut bacteria and the severity of COVID-19 infections.1
The importance of gut health has never been clearer. Our scientific understanding of the microbiome—the trillions of bacteria, fungi, and viruses that live in and on our body, especially in the gastrointestinal tract—has grown leaps and bounds since Hippocrates’ time, and even since the last century. Doctors and researchers have much better tools for testing gut health and sequencing the microbiome than they did just a decade ago.
So all the world’s health issues solved, right? Not exactly.
Gut health is complicated. The more you learn, the less you realize you know… and the less you realize anyone knows. New microbes are still being discovered.2 We’re just scratching the surface in terms of understanding specific microbes’ roles in a healthy or dysfunctional gut. And while scientists are actively working on therapies to manipulate the microbiome and improve health, there is still a long way to go.
All that said, we do have a good understanding of what it takes to improve gut health naturally. We know the core, foundational things everyone can and should be doing and what they shouldn’t be doing. Top-down micromanagement might not work yet, but big-picture, bottom-up intervention does.
That’s what we’re covering today: the best strategies to maintain and improve gut health.
What is “Gut Health” Anyway?
“Gut health” is one of those terms that gets thrown around a lot with little discussion about what it actually means. The hallmarks of a healthy gut are
Good microbial diversity and appropriate balance. Having the right numbers of “good microbes” in the right proportions in the right parts of the GI tract. Not having too many “bad microbes” anywhere.
Not “leaky.” Permeable enough to allow beneficial molecules like nutrients to be absorbed into the body, not so permeable that waste and other potentially harmful substances also cross the gut barrier.
Good motility. Food moves through neither too quickly nor too slowly.
Able to absorb nutrients, which depends on the integrity of the gut lining and the composition of the microbes living in different sections of the gut.
Many things can cause your gut to become unhealthy. There are acute situations like food poisoning or taking a round of antibiotics, but your gut can also be chronically unwell due to things like chronic stress, poor sleep, overexercising, smoking, excessive drinking, or poor diet. Gut microbiome composition also shifts with age, and those changes may be partially responsible for the so-called diseases of aging.3
Signs or Symptoms of an Unhealthy Gut
Some of the signs are obvious. If you have chronic constipation, diarrhea, bloating, or gas, your gut is in bad shape.
Others are more pernicious. Less obvious indications of an unhealthy gut include
It’s not an exaggeration to say that if you have any chronic disease, or any of the other signs of leaky gut, you could benefit from taking steps to improve your gut health. Luckily, there are plenty of things you can do to shore up your gut, all of which will have widespread positive effects on your health.
How to Improve Gut Health Naturally
When the average person exhibits signs of poor gut health, they run to the pharmacy for laxatives, antidiarrheals, or antacids. Those may alleviate some of the symptoms in the short term, but they do nothing to address the underlying issues. In fact, they may make them worse.
If you need immediate symptom relief, or if you’re dealing with an acute run-in with bad shellfish, by all means, take the meds. But for longer-term fixes, do the following.
Start with diet
Not surprisingly, what you eat (or don’t eat) is one of the biggest determinants of gut health. The goal here is simple: eat foods that help, avoid foods that hurt. But what does that mean?
For a healthy gut, you want to consume things that support a well-balanced microbiome, meaning things that encourage the growth of beneficial microbes and discourage, or at least do not accelerate, the growth of harmful pathogens. You also want to consume foods that are likely to maintain a robust intestinal lining and avoid those that contribute to permeability and leaky gut.
The best foods for gut health include
Foods that contain ample prebiotic (fermentable) fiber. Prebiotics nourish the microbes living in your gut. The microbes ferment certain types of fiber and generate beneficial byproducts like butyrate that maintain the integrity of the gut lining and serve other important functions in the body. Vegetables and fruits, nuts and seeds, and legumes all contain prebiotic fiber. Some of my favorite sources are avocado, asparagus, mushrooms, pistachios, Jerusalem artichokes, and alliums like garlic and onions.
Fermented foods. When you buy any fermented foods that contain live cultures, that’s code for “probiotics,” or beneficial microbes that populate the gut. Yogurt, kefir, kimchi, sauerkraut, fermented pickles, natto, or any other fermented food is great as it still contains live bacteria. Items that have been heat sealed, as with home-canned or shelf-stable goods, lose their probiotic properties.
Polyphenol-rich foods. Polyphenols are plant compounds that also feed your gut bacteria. Berries, dark chocolate, and coffee are excellent sources that, not coincidentally, are correlated with favorable microbial profiles.456 Red wine also contains polyphenols, but don’t go overboard with the zin in the name of gut health.
Skin, bones, and broth. Skin, bones, and broth provide “animal fiber”—collagenous and gristly substrate that our gut bacteria can digest and prosper on. They also offer ample amounts of gelatin, which can help repair a damaged gut lining. (In a pinch, collagen can fill the gap.)
I recommend working as many of these into a week’s worth of meals as you can.
On the other hand, it should just be common sense to avoid foods that can actively impair the health of your gut. The prime suspects here are ultra-processed foods, artificial sweeteners, and gluten-containing grains. Especially if you know your gut health is already less-than-perfect (and almost everyone’s is), be very wary of these items.
Practice good oral hygiene
Most people don’t know that periodontitis (gum disease) is a major risk factor for colorectal cancer. Some estimates suggest that one-third or more of colorectal cancers are caused or exacerbated by the oral pathogens Fusobacterium nucleatum and Porphyromonas gingivalis.7 When they migrate from the mouth to other parts of the body, they can cause inflammation, promote tumor growth, and reduce the effectiveness of anti-cancer therapies.8 Scary stuff! And all the more reason to take care of your chompers.
On a related note, you’ve probably heard the saying that “digestion begins in the mouth.” Besides keeping a healthy oral environment—which contains its own microbiome, by the way—make sure to chew your food thoroughly. Mechanically breaking it down and mixing in salivary enzymes are the crucial first steps in extracting nutrients, amino acids, and so on.
If you’re dealing with IBS, constipation, anxiety, or other symptoms of gut dysbiosis, probiotics may be able to help. Research is still fairly new in these areas, but we do have some data to suggest that certain probiotic strains may be particularly helpful depending on your symptoms.
Don’t be too sanitary
Too sterile an environment causes too sterile a gut. We are made to spend time in nature, getting our feet and hands dirty, exposed directly to the natural soil teeming with trillions of bacteria. We’re meant to eat produce directly from the ground. (That said, if you didn’t grow it yourself, it’s best to wash your produce.) Exposure to healthy soil may even bestow upon us gut microbes that make us less anxious.9
Along these lines, a study in infants aged three to four months found that exposure to household disinfectants was correlated with unfavorable changes to the gut microbiome,10 so strongly consider switching to non-toxic cleaning solutions in your home.
Work on reducing stress and improving sleep
As if you need another reason for me to harp on you about sleeping more and stressing less, there’s ample evidence that poor sleep and chronic stress wreak havoc on your gut.
These Are the Basics
In many ways, supporting a healthy gut comes down to implementing the basic Primal principles I recommend all the time. They’re the things that every human needs—ample nutrient-dense, minimally processed foods, interaction with nature, plenty of restorative sleep, absence of chronic stress (as a goal, perhaps not a realistic one)—regardless of current or future health or longevity goals.
Gut health is fundamental to every aspect of wellness, so don’t wait until you have major issues to start caring about your microbial passengers. Maintaining a healthy gut will always be easier than fixing a dysfunctional one. Once you’re experiencing symptoms like the ones listed above, these foundational practices are still important, but you’ll probably also want to enlist a practitioner who can help diagnose the specific root causes and recommend individualized treatments.
Thanks for reading, everyone. If you have any questions about gut health or the info contained in this post, let me know down below!
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.