BAS Health Series: Healthy Body Functions, Article 4 of 5
If the brain is the control center and the heart is the engine, your gastro-intestinal system — your gut — is the foundation that keeps everything running smoothly. It’s where nourishment, immunity, and energy all begin.
Over the years, I’ve come to realize just how critical this system really is — and how many people quietly suffer when it’s not working properly. Several members of my family, myself included, have dealt with GI problems. It’s one of those struggles people often endure in silence — chronic discomfort, fatigue, bloating, irregularity — things that seem small until they start controlling your day. But learning to understand and correct those problems is life-changing.
And beyond digestion, the gut plays a much bigger role than most realize. It’s connected to the immune system, the brain, and even long-term disease prevention. In fact, over 70% of your immune system lives in your gut¹. A healthy gut supports mental clarity, helps prevent cancer, and even contributes to a longer, healthier life.
What Is Your Gastro-Intestinal System and How Does It Work?
Your GI system isn’t just your stomach — it’s an intricate, intelligent network of organs that fuel your body and remove toxins.
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Stomach: Uses acid and enzymes to break down proteins and prepare nutrients for absorption.
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Small intestine: A 20-foot tube lined with villi that absorb vitamins, minerals, and amino acids.
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Large intestine (colon): Extracts water, forms waste, and houses trillions of beneficial bacteria that influence digestion, mood, and immunity².
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Liver: Detoxifies harmful substances, processes nutrients, and produces bile to digest fats.
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Kidneys: Filter nearly 50 gallons of blood daily³, balancing hydration and removing toxins.
Did You Know? The surface area of your small intestine is roughly the size of a tennis court⁴ — all dedicated to absorbing the nutrients that sustain you.
What Does It Mean to Improve GI Health?
Improving gut health means optimizing how your body digests, absorbs, and eliminates. It also means supporting the ecosystem of bacteria — known as the microbiome — that shapes immunity, mood, and metabolism.
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Better nutrient absorption: Ensures your body gets what it needs to thrive.
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Stronger immune system: Gut bacteria “train” your immune cells to recognize real threats⁵.
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Reduced inflammation: Balances immune response and protects organs.
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Improved mood: Gut bacteria produce neurotransmitters like serotonin and dopamine⁶.
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Longer life: Balanced microbiomes are linked to lower risk of heart disease, obesity, and cancer⁷.
Issues and Diseases That Can Occur
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Irritable Bowel Syndrome (IBS): Common and often triggered by stress, poor diet, or imbalanced microbiota.
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Ulcers: Caused by H. pylori infection or chronic stress.
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Inflammatory Bowel Disease (IBD): Chronic inflammation from immune dysfunction.
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Fatty liver disease: Rising dramatically, even in younger adults, due to diet and inactivity.
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Colorectal cancer: The second leading cause of cancer deaths in the U.S.⁸.
Roughly 60 to 70 million Americans experience digestive diseases each year⁹ — but many never seek help. Stop living in pain and discomfort. See a specialist!
The Gut and the Immune System
Your gut is the headquarters of your immune system. The bacteria living in your intestines (known as gut flora) help regulate inflammation, produce antibodies, and maintain the integrity of your intestinal wall¹⁰.
When the gut lining becomes damaged — a condition often called “leaky gut” — bacteria and toxins escape into the bloodstream, triggering chronic inflammation that weakens your immune system and can contribute to autoimmune diseases¹¹.
A diverse microbiome can reduce immune-related inflammation by up to 50%¹², which you know from previous articles helps prevent cancer and heart disease.
The Gut and Mental Health
Your gut and brain are in constant communication through the gut-brain axis — a two-way network of nerves, hormones, and immune messengers. The gut produces around 90% of your serotonin, the neurotransmitter that regulates mood¹³.
When your gut is imbalanced, your mood often follows. Anxiety, depression, and brain fog are now known to be closely tied to gut dysbiosis.
Studies show people with depression often have 30% fewer beneficial gut bacteria than those without¹⁴.
The Gut and Cancer Prevention
A healthy gut microbiome also plays a major role in cancer prevention. Beneficial bacteria break down fiber into short-chain fatty acids that suppress tumor growth, support detoxification, and reduce DNA damage¹⁵.
Colon cancer, in particular, is strongly linked to diet and gut health — one of the most preventable cancers when caught early and supported with lifestyle changes. High-fiber diets can reduce colorectal cancer risk by up to 40%¹⁶.
Simple Things You Can Do Every Day to Improve GI Health
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Eat more fiber: Supports healthy bacteria and promotes regular digestion. People who consume 25–30g of fiber daily have significantly lower inflammation¹⁷.
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Include probiotics and prebiotics. Probiotics are live bacteria found in yogurt, kefir, and fermented foods that improve gut balance. Prebiotics are the plant fibers (like garlic, bananas, and oats) that feed those bacteria¹⁸. Prebiotics can increase beneficial gut bacteria by up to 10-fold in just weeks¹⁹.
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Stay hydrated: Water helps the digestive process, supports the kidneys, and allows nutrients to flow freely. Mild dehydration can slow digestion and reduce nutrient absorption²⁰.
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Manage stress: Stress changes gut motility and microbial balance, triggering discomfort and inflammation²¹. Chronic stress can alter gut bacteria diversity by 30%²².
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Exercise regularly: Physical movement promotes gut motility and increases beneficial microbial diversity. Regular exercisers have 20% higher levels of good bacteria²³.
Things You Should Avoid That Damage Your Gut
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Processed foods and sugar: Feed harmful bacteria and fuel inflammation.
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Antibiotic overuse: Destroys healthy gut flora.
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Excess alcohol: Damages the gut lining and disrupts absorption.
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Dehydration: Reduces nutrient delivery and toxin removal.
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Ignoring symptoms: Chronic bloating, heartburn, or constipation are signals your gut needs attention.
Why This Matters
This article is a bit personal. GI health has affected people I love — and like so many families, we’ve often suffered quietly. Digestive problems carry a stigma; they’re not easy to talk about. But when you start learning what’s really happening in your gut — and how connected it is to your entire body — everything changes.
Your gut is your body’s foundation. When it’s unbalanced, everything else struggles. But when it’s strong, your whole body comes alive again.
Visiting medical and research centers over the years, I’ve seen firsthand how gut health influences immunity, mental health, and even cancer recovery. The science is clear — this is not fringe wellness; this is fundamental biology. And yet, it’s still one of the most overlooked topics in healthcare.
For me, helping people understand this connection isn’t just about education — it’s about giving people back control of their health, their energy, and their confidence. Learning how to care for your gut can truly change your life.
Healthy Core Body Functions Series
By Ken York, President of Benefit Airship
At Benefit Airship, our passion is helping members get the best healthcare possible. We’re endlessly curious about what makes the body thrive—and we love uncovering insights that make health simpler to understand and easier to manage. Whenever we find something worth sharing, we share it to empower healthier, more informed lives.
This series will explore five essential body systems—the brain, heart, immune, gastrointestinal, and nervous systems—and offer practical tools for improving your overall well-being. I’ll share science, tips, and inspiration for taking small, meaningful steps toward a stronger, healthier you.
Sources
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National Institutes of Health, Gut Microbiome and Immunity
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Harvard Health, How the Gut Microbiome Affects Overall Health
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Johns Hopkins Medicine, Liver and Kidney Function Overview
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Scientific American, Surface Area of the Small Intestine
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Nature Reviews Immunology, Gut-Immune System Interaction
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Journal of Neuroscience, Serotonin and the Gut-Brain Axis
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BMJ, Microbiome Diversity and Longevity
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CDC, Colorectal Cancer Statistics (2025)
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National Institute of Diabetes and Digestive and Kidney Diseases, Digestive Disease Statistics
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Frontiers in Immunology, Gut Barrier and Immune Regulation
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Mayo Clinic, Leaky Gut and Systemic Inflammation
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Gut Journal, Microbial Diversity and Inflammation Reduction
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Harvard Medical School, Serotonin and Gut Health
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Nature Microbiology, Depression and Gut Bacteria Correlation
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Cancer Prevention Research, Microbiome and Tumor Suppression
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American Journal of Clinical Nutrition, Dietary Fiber and Colorectal Cancer Risk
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Nutrients Journal, Fiber Intake and Inflammation Biomarkers
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Johns Hopkins Medicine, Prebiotics vs. Probiotics Explained
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Cell Host & Microbe, Prebiotic Supplementation Study
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American Journal of Physiology, Hydration and Digestive Efficiency
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Psychosomatic Medicine, Stress and Gastrointestinal Disorders
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PNAS, Stress-Induced Changes in Gut Microbiota
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Microbiome Journal, Exercise and Microbial Diversity
