Functional Wellness, Part 3: Digestive Health

A well-functioning digestive system is the cornerstone of good health. Find out how the gut works, what makes it vulnerable — and what you can do to keep your own digestive tract in tiptop shape.

Digestive Health

Editors’ note: For more than 15 years, celebrated author and pioneering medical visionary Mark Hyman, MD, has been practicing and promoting a revolutionary healthcare concept known as functional medicine. It’s a patient-centered (vs. disease-centered) approach that focuses on identifying and addressing the root causes of chronic health challenges as opposed to merely treating symptoms. Functional medicine also emphasizes incorporating nutrition and lifestyle solutions rather than relying exclusively on pharmaceutical and surgical interventions. Experience Life is proud to bring you this six-part series in which Dr. Hyman describes the emerging practice of functional medicine and explains how it can improve your well-being.

Digestive distress is hardly a topic for dinner-party conversation, but the truth is, it’s surprisingly common. About one in three Americans suffers from gut problems of various sorts. Two of the top seven best-selling drugs in the United States are prescribed for gastrointestinal problems. And nearly half of all visits to internists are for “functional bowel disorders,” such as reflux and irritable bowel syndrome.

Doctors use the word “functional” to describe problems related to function — situations where the bowel simply isn’t working properly — as opposed to “structural” disorders, which are something we can see (e.g., blockages, punctures, malformations), and which therefore are often considered more “real.” But functional gut disorders are equally real problems with very real causes — and sometimes dire consequences.

Considering how many people suffer from these problems, you would think our sophisticated medical system would have a clear understanding of the causes of irritable bowel syndrome, constipation, diarrhea, reflux, inflammatory bowel disease and other common digestive issues. You would think by now we’d have developed great treatments to fix these problems.

Unfortunately, our understanding of this highly sophisticated and integral part of our body is still quite primitive, despite the explosion of scientific research on what Science magazine has called “the inner tube of life.”

As it turns out, digestive problems aren’t just digestive problems. They can cause many other seemingly unrelated diseases, a fact that has escaped most people — including many doctors.

Over the last 15 years of practice and research, I have found the gut to be the source of inestimable suffering throughout the body. Yet, when you treat the digestive problem, the other symptoms often improve. These treatments promise relief from common “functional” gastrointestinal symptoms (and most allergic and autoimmune diseases, which originate in the gut), but they’ve also proven effective against illnesses ranging from depression and attention deficit hyperactivity disorder (ADHD) to dementia and Parkinson’s disease.

Sound crazy? Let me tell you about one of my patients. She was 57 and had suffered for eight years from severe, unrelenting eczema all over her body. She saw doctor after doctor for this red, oozing, scaly, itchy rash. They gave her salves, lotions, steroids and antibiotics. But they never addressed the underlying cause of her problem.

When she came to me, I learned she ate a high-sugar diet and suffered from frequent yeast infections. She also had a leaky gut, which is known in medical terms as “increased intestinal permeability” — in other words, the gut-wall barrier was not working. Plus, she had developed 24 immunoglobulin G (IgG) food allergies, and her stool lacked healthy bacteria and showed an overgrowth of yeast. She also had very high blood antibodies against yeast.

The answer? I treated her skin by treating her gut. I asked her to stop eating the foods to which she had reactions, told her to stop feeding the yeast by cutting out sugar and refined carbohydrates, and helped her kill the yeast in her gut with antifungal medications and herbs. Then I replenished the healthy bacteria and healing gut nutrients. The result? Her eczema disappeared — and it has never come back.

How Your Gut Works

Many people think of their digestive systems as a series of tubes through which food is mechanically crushed and extruded. It’s not as simple as that. Your gut’s health determines which nutrients are absorbed and which toxins, allergens and microbes are repelled. As a result, it is directly linked to the health of your entire body.

Intestinal health could be defined as the optimal digestion, absorption and assimilation of food. But that is a big job that depends on many other factors.

First, the bugs in your gut function like a rainforest — a diverse and interdependent ecosystem. The 3 pounds of bacteria there include some 500 different species that act as a chemical factory — helping you digest your food, produce vitamins, regulate hormones, excrete toxins and produce healing compounds that keep your gut healthy.

But for you to be healthy, these bacteria must be in balance. Too many of the wrong bugs, like parasites, yeasts and bad bacteria — or not enough of the good bugs, like lactobacillus or bifidobacteria — can seriously damage your health. (For more on good bugs and bad, see “Good Bacteria Welcome”.)

Second, the gut is delicate. Your entire immune system and the rest of your body are protected from the toxic environment in the gut by only a one-cell-thick layer — the epithelium — that covers a surface area the size of a tennis court! If that barrier is damaged, you will get sick and your immune system will become overactive, producing inflammation throughout the body.

And then there’s your second brain. That’s right, your second brain. Your gut literally contains its own nervous system. In fact, the ”brain” in your gut contains more neurotransmitters than the brain in your head.

The intestinal nervous system is wired back to your brain, and messages travel between the two. When those messages are altered for any reason in any direction — from the brain to the gut or the gut to the brain — your health will suffer.

But wait, there’s more: Your gut also has to dispose of all the toxins created as a byproduct of your metabolism. If things get backed up, your entire body can become overrun with toxins.

Finally, in the midst of all of this, your gut must break down all the food you eat, separate all the vitamins and minerals, and shuttle everything across the epithelium into your bloodstream for you to stay healthy.

Enemies of a Healthy Gut

With such a delicate balance and so many ways for things to go wrong, it’s no wonder that so many of us are sick. Even in a perfect world, our gut has a hard time keeping things balanced. In the challenging circumstances of real life, there’s seemingly no end  to the things that knock our digestive systems off balance. They include:

    • A standard American diet (SAD) that is low in fiber, rich in sugar, low in nutrients, and high in additives and chemicals, changing the ecosystem of our guts
    • Overuse of medications, such as anti-inflammatories, antibiotics, acid-blocking drugs (see “The Dangers of Acid-Blocking Drugs,” below) and steroids, that disrupt the gut’s ability to stay in balance and do its job
    • Chronic low-grade infections or gut imbalances with bacterial or yeast overgrowth, parasites, or even more serious gut infections
    • Exposure to toxins, such as mercury and mold, that damage normal gut function
    • Lack of adequate digestive enzyme function, which can be caused by acid-blocking medications or zinc deficiency
    • Chronic stress, which can alter the gut’s nervous system, causing a leaky gut and changing the normal bacteria in the gut

By now you probably have a better sense of why those “functional” bowel disorders I mentioned earlier are so widespread — and why most conventional treatments fail to address the underlying problems. All in all, we live in dangerous digestive times.

Fighting Food Allergies

As I noted before, it’s a rare digestive problem that remains confined to the gut. One consequence of poor diet, stress, medications, infections or toxins damaging the balance of normal gut function is that our ability to tolerate food we normally eat is impaired — in other words, we become sensitive or allergic to certain foods.

All these factors can damage the delicate lining of the small intestine, which, in turn, will harm healthy bowel bacteria, creating injury and inflammation in that one-cell layer of gut lining.

When that happens, we develop a leaky gut. Because many of our digestive enzymes (the chemicals that break down our food) are located right on that delicate epithelial layer that is now damaged, we cannot digest our food properly. Suddenly, we have partially digested food particles from normally innocuous foods “leaking” into our circulation.

And, because about 60 percent of our immune system is located in the gut, beneath that one-cell layer, our bodies react by increasing our immune response and generating inflammation. Our immune system, normally used to seeing fully digested foods (like proteins broken down into amino acids, fats broken down into fatty acids and carbohydrates broken down into simple sugars), suddenly “sees” foreign (meaning partially digested) molecules.

So it does what it is designed to do: attack and defend! That is how we create antibodies and develop IgG allergies to common foods. This is what makes us sick and fat, toxic and inflamed, depressed and anxious.

How to Heal Your Gut

So, how do you bring your gut back into balance? Here’s the plan I use with patients whose digestive distress has caused other health problems. See how it works for you.

  1. Eat whole, unprocessed foods that contain plenty of fiber, like vegetables, beans, nuts, seeds and whole grains.
  2. If you think you might have food sensitivities, try an elimination diet. Cut out gluten, dairy, yeast, corn, soy and eggs for a week or two and see how your gut feels and what happens to your other symptoms.
  3. Immediately treat any infections or overgrowth of bugs, like parasites, small bowel bacteria or yeasts.
  4. Take digestive enzymes with your food.
  5. Take probiotic supplements, which contain healthy bacteria for your ecosystem.
  6. Take supplements of omega-3 fats, which help cool gut inflammation.
  7. Use gut-healing nutrients such as glutamine and zinc.

If you think you have “just” a digestive problem, think again. Having a healthy gut doesn’t simply get you relief from bloating, gas, heartburn or constipation: A healthy gut is central to your overall health, and it is connected to everything that happens in your body. Keeping your digestive system healthy is critical, because, ultimately, you are not only what you eat — you are what you absorb.

, is the medical director and founder of The UltraWellness Center in Lenox, Mass., and the former medical director at Canyon Ranch health resort. He has authored several best-selling books, including UltraMetabolism: The Simple Plan for Automatic Weight Loss (Scribner, 2006), UltraPrevention: The 6-Week Plan That Will Make You Healthy for Life (Scribner, 2003), and The UltraSimple Diet (Pocket Books, 2007). Dr. Hyman also is editor in chief of the peer-reviewed journal Alternative Therapies and a leading expert in functional medicine. For more information, see

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