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Digestive Health and the Immune System By Gayle Madeleine Randall, MD

Digestive Health and the Immune System

Happy Gut Happy Life

By Gayle Madeleine Randall, MD.


We all have passengers inside of us.  There are 100,000 times more microbes in your gut than there are people on earth, and 30,000 times more gut microbes than cells in your body. Moreover, we have a symbiotic relationship with these passenger bacteria living inside our bowel.  They need us and we need them. The normal human gastrointestinal tract contains hundreds of different species of harmless bacteria, referred to as intestinal flora.

When the normal balance of these bacteria is disturbed by poor diet and lifestyle, illness, stress or antibiotic treatment, the common effects are diarrhea and/or constipation, gas, bloating and abdominal pain.  Our immunity suffers.  The resulting imbalance also leads to overgrowth of unfriendly bacteria, resulting in candida or yeast.  Without correction, it can contribute to arthritis, irritable or leaky bowel syndrome, immune suppression, mal-digestion, indigestion, gas, and chronic diseases and even autoimmune disease. These can be diagnosed easily with RNA stool testing and treated with probiotics, diet and herbs.

Healthy bacteria are central to a healthy gut. But there’s more — the immune and neuroendocrine functions of the gut. This can be traced to the thymus. Humans are the only mammals born with a thymus that then involutes, by the time we’re pre-adolescent. It leaves behind “T cells,” which are responsible for fighting virus, fungus and other immune functions for the rest of our lives. 

How is that, if the host organ goes away? When the thymus involutes, all of those crucial immune T cell warriors settle in the gut, where they set up a string of camps in the intestine called Peyer’s patches. They also move into our bone marrow. Right now, you hold an enormous number of immune cells and lymph nodes in your intestinal tract, all of which play a role in immunity.  

            In addition your gut and brain are connected through chemicals called neurotransmitters. Serotonin calms you and helps with sleep. Your gut bacteria also produce a gamma-aminobutyric acid (GABA), which helps control feelings of fear and anxiety. Neuroendocrine cells play into the fight-or-flight reaction by producing Norepinephrine and Epinephrine. Our gut and our brain communicate through myriad neuroenteric and neurotransmitter messages, along with the vagus nerve.

            The enteric nervous system uses more than 30 neurotransmitters similar to the brain. About 95 percent of the body’s serotonin comes from the gut, which may be how the gut, or “second brain,” influences well-being or mood. In a Feb. 12, 2010 article in Scientific American, Dr. Michael Gershow, chairman of the Department of Anatomy at New York Presbyterian Hospital and Columbia University Medical Center, and author of The Second Brain, wrote, “The second brain doesn’t help with the great thought processes… religion, philosophy and poetry are left to the brain in the head.” Meantime, Emeran Mayer, author of The Mind-Gut Connection, talks about a very intricate, complex communication system between the gut and mind, including information from abundant endocrine cells amounting to the body’s largest endocrine organ, the gut’s immune system.

According to Mayer, they reside in a chain of lymph node-like villages (Peyer’s patches) and capable of producing cytokines (inflammatory molecules). These gut-based immune cells are outside the gut space and alongside dendrite cells, which may extend into the gut and interact with the microbiome of the gut.  Cytokines can enter the blood stream by crossing the gut lining and getting to the brain. Endocrine cells signal the brain through the vagus nerve.

            All in all, these messages and communicating molecules definitely interact with the brain. So who can say which thoughts are affected? Feelings are affected, so thoughts associated with those feelings must result — possibly in a poem, song, or warning signals.

            Our food choices are critical. Sadly, industrialized farming over the past 100 years has changed the American diet from largely organic to largely processed foods high in sugar and fat, low in fiber, and chemically contaminated. This has altered our gut mitochondria, causing a multitude of diseases and symptoms — diabetes, neurologic diseases like Alzheimer’s and Parkinson’s, obesity, inflammatory diseases, inflammatory bowel disease, inflammatory bowel syndrome, diarrhea, constipation, arthritis, autoimmune diseases, digestive disorders, depression, anxiety, food sensitivities, allergies, fatigue, and several forms of cancer. Many diseases and symptoms that seem unrelated are actually caused by gut problems and imbalanced microbiota. Gut health literally affects your entire body.

            The gut houses three pounds of bacteria and up to 500 species of microbiota. These have been shown to have an effect on the brain. Imbalanced and affected gut microbiota are associated with all kinds of symptoms such as brain fog, fatigue, achy joints, and the diseases noted above.

Two other crucial terms connected with gut health and the immune system are probiotics and antibiotics. Probiotics exploded into the grocery and health food stores over the last decade. Antibiotics have been around for many decades and have saved lives. However, they often lower the numbers of beneficial bacteria in the body along with their intended targets.

Good bacteria in the form of probiotics work by colonizing mostly the large intestine and crowding out disease-causing bacteria, thereby restoring balance to the intestinal flora. They may also produce substances that inhibit pathogenic bacteria, compete for nutrients with them, stimulate the body's own immune system, and prevent unhealthful immune reactions to unfriendly bacteria and yeast.

Probiotic supplements are available in varied forms such as yogurt fermented foods, capsules, gummies, tablets, beverages, teas (such as kombucha tea) and powders. Probiotics should not be confused with prebiotics, which are complex sugars (such as inulin from soluble fibers in most plants, and fructo-oligosaccharides) that are ingested as fuel for bacteria already present in the gastrointestinal tract; although prebiotics and probiotics are sometimes combined in the same product and termed synbiotics.

Probiotics such as Saccharomyces boulardii, Enterococcus faecium and Lactobacillus have been clinically proven to prevent antibiotic-caused diarrhea. Successful clinical trials have been conducted using Lactobacillus to treat H. pylori infection and Lactobacillus plantarum to treat irritable bowel syndrome. Lactobacillus GG (a strain of L. rhamnosus) and Lactobacillus reuteri have been shown to reduce the duration of diarrhea, due to infectious diarrhea.    

The best probiotics, are in the refrigerated section. Lactobacillus acidophilus and Bifidobacter are the most important bacteria to look for on the label, although there may be many others.  Lactobacillus acidophilus. A typical dose should supply at least 3 to 50 billion live organisms per capsule.  Take the product right after eating, as the acid in the stomach is lowest at this time.

             The balanced gut microbiome that results from our diet, self-care and probiotic use is essential for optimal digestion, absorption and integration of nutrients, and elimination. When optimal, it supports a healthy inflammatory response and keeps our immune system strong, while also supporting our emotions by balancing our neurotransmitters. Here are some helpful food choices to keep your microbiome balanced:

            Asparagus – prebiotic

            Sauerkraut or Kim Chi – good source of probiotics and fiber

            Garlic – prebiotic; discourages growth of dysbiotic bacteria

            Onion – prebiotic and antioxidant 

            Apple cider vinegar – stimulates digestive juices; helps break down foods

            Ginger – relaxes stomach assists digestion treats nausea, increases warmth (chi)

            Dandelion greens or cilantro – anti-inflammatory and cleansing detoxifying chelates toxins

No matter how dedicated we are to gut health, we must deal every day with an environment that is decidedly unhealthy. We used to be the same inside as what our environment was outside. We repopulated our intestinal tracts by simply eating off the trees and the land, creating a state of harmony between the environment and ourselves, the way all Native peoples lived. Well, today, the vast majority of our nation’s food supply is anything but organic. Instead, it is sterilized, pasteurized, irradiated, plastic-wrapped, pasteurized, microwaved, and processed in a number of other ways that renders it almost nutritionally sterile.

            Many farmers have been forced to use as pesticides and fertilizers by companies such as Monsanto in agribusiness to grow our food supply! There are also new super viruses and parasites that we cannot risk ingesting or transmitting; our colossal battle with the coronavirus is a perfect example.  

            What you eat and how you live can affect your immunity and emotional balance through your gut. Eat well, a plant based, low refined carbohydrates and avoid vital gluten. Vital gluten is an industrialized gluten that is added to many foods, even meats and vegetable products. Which leads to a controversial issue — gluten itself. It seems that pure gluten drawn from the semolina seed has its own anti-gluten molecule within it. Gluten grown in the United States is 2/3 larger than the original seed, and contains glyphosates and other chemicals. Neither is beneficial for our health. The vast majority of my patients who remove gluten from their diets experience fewer symptoms of what ails them, and their gut health improves markedly.

            So in summary, how do we balance our gut and care for our microbiome? First of all, we need to remove from our diet all the foods developed since 1970 through industrialized farming. This includes refined sugars, refined fructose, animal fat and mass-produced food. Choose organic, locally grown whole food, mostly plant-based. Plants contain the valuable prebiotics on which microbiomes live, in the form of soluble fiber and inulin. Plant oils, especially first-pass, cold-pressed olive oil, have polyphenols that are metabolized by gut flora, providing anti-inflammatory benefits to both body and brain.

            Optimize your microbiome by eating and taking naturally fermented foods and probiotics. The jury is still out on which probiotic organisms are the best; it may vary according to the individual and condition. However, we do know we need a mix of Lactobacillus and Bifidobacteria. If yeast is involved, then Saccaromyces boulardi can be helpful. Your probiotic should contain live bacteria and be at least 50 billion flora per capsule.

            Stool testing is also the approach recommended by Emeran Mayer in The Mind-Gut Connection. “A gut microbial analysis from a simple stool sample (through an RNA or MAP test) could become one of the most powerful screening tools in healthcare,” he wrote. That’s exactly what it is for me today and I have been practicing in one way or another for more than 20 years.

            Mayer also recommends using mindfulness meditation to tune into messages from the gut. “By becoming more aware of these gut feelings, those associated with good and bad gut reactions, you can better regulate your own emotions.” I believe emotions can begin in the gut, and then be sent to the brain through the complex communication system I’ve described. It is only then that the brain decides what to make of them.

Gayle Madeleine Randall, MD, has over forty years of direct experience as a physician, scientist, cross-cultural practitioner, administrator and writer to her endeavors. After graduating with high honors from the University of Nebraska Medical School, she completed an Internal Medicine residency and Gastroenterology fellowship at UCLA hospitals and clinics. From 1988-94, as Associate Professor of Medicine at UCLA, she became one of the first physicians in the nation to introduce and teach Complementary Alternative Medicine to medical school students. She also served as the Director of the Medical Procedures Unit for the West Los Angeles Veterans Administration hospital, while becoming proficient in numerous Western and Eastern healing modalities. During this time, years after serving her medical clerkship as the lone doctor on a Sioux reservation, Dr. Randall’s long interest in Native American and non-traditional forms of medicine, healing, dream work and spirituality also blossomed.


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