Gastrointestinal symptoms are incredibly prevalent worldwide. A large-scale, multinational study found that over 40% of people worldwide have at least one functional gastrointestinal disorder (FGID), characterized by disruptive chronic and recurrent gastrointestinal (GI) symptoms without observable changes to GI anatomy (11). An estimated 11% of Americans suffer from a chronic digestive disease, with the prevalence as high as 35% in those over 65 (12).

The presence of GI symptoms and the necessity of medical care substantially impact physical, emotional, and socioeconomic burdens related to overall health. Additionally, while a conventional approach to treatment may be required in some instances, many of the commonly prescribed medications for GI symptoms and diseases are associated with adverse GI effects (13, 14). Implementing complementary and integrative medicine can greatly alleviate symptoms, increase quality of life, and prevent GI side effects.

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Function of The Gastrointestinal Tract

The digestive system, composed of the GI tract, salivary glands, liver, gallbladder, and pancreas, functions to digest and absorb ingested nutrients and eliminate waste products from the body. The following organs make up the GI tract:

Mouth

Digestion begins in the mouth through the mechanical forces of chewing and the chemical actions of salivary enzymes. The mixture of food with saliva begins the breakdown of starches and lubricates the food to make the transition through the esophagus easier. (15, 16)

Esophagus

Involuntary esophageal muscle contractions propel the food bolus into the stomach. The lower esophageal sphincter (LES) relaxes, allowing food to pass from the esophagus into the stomach. (16)

Stomach

Acid and digestive enzymes in the stomach mix with food to continue the chemical breakdown of carbohydrates and proteins. The final result is a mixture called chyme, which is slowly emptied by the stomach into the small intestine. (15, 16)

Small Intestine

Digestive enzymes produced by the small intestine and digestive accessory organs continue to break down the chyme into absorbable nutrients. Nutrients are absorbed through the semipermeable small intestinal wall into the bloodstream. Peristalsis pushes chyme through the three portions of the small intestine (duodenum, jejunum, and ileum) until it reaches the ileocecal valve and transitions into the large intestine. (15, 16)

Accessory Organs

Digestive enzymes and juices produced and secreted by the liver, gallbladder, and pancreas into the small intestine act to digest carbohydrates, fats, and proteins into their absorbable building blocks. (15)

Large Intestine

The large intestine is primarily responsible for absorbing water and propelling digestive waste to the rectum for elimination. The large intestine also houses the intestinal microbiome, responsible for further digestion and synthesis of nutrients, immune system modulation, and production of signaling molecules. (15, 16)

Rectum

The rectum is the final portion of the large intestine. It stores stool until it is evacuated through the anus during a bowel movement. (16)

Common Gastrointestinal Disorders

Digestive diseases affect 60-70 million people, accounting for almost 50 million outpatient care visits annually. Per the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the most common digestive diseases include:

• Foodborne Illness & Non-Foodborne GI Infections. Prevalence: A combined prevalence of 211 million
• Gastroesophageal Reflux Disease (GERD). Prevalence: 66 million people experience weekly symptoms
• Chronic Constipation. Prevalence: 63 million
• Gallstones. Prevalence: 20 million
• Peptic Ulcer Disease (PUD). Prevalence: 15.5 million
• Irritable Bowel Syndrome (IBS). Prevalence: 15.3 million
• Hemorrhoids. Prevalence: 75% of people over age 45
• Abdominal Wall Hernia. Prevalence: 3.6 million
• Liver Disease. Prevalence: 3 million‍
• Pancreatitis. Prevalence: 1.1 million

Common Gastrointestinal Symptoms

The 2019 National GI Survey audited 71,812 individuals to determine the prevalence of GI symptoms in the American population. The study concluded that 61% of Americans experience at least one GI symptom weekly. According to this survey, the most commonly experienced symptoms were heartburn/reflux (30.9%), abdominal pain (24.8%), bloating (20.6%), diarrhea (20.2%), and constipation (19.7%), nausea/vomiting (9.5%), difficulty swallowing (5.8%), and bowel incontinence (4.8%). (17)

The ACG notes that indigestion, belching, and flatulence are also common GI symptoms.

Possible Causes of Gastrointestinal Distress

The development of gastrointestinal disease and symptoms is multifaceted, including factors such as genetics, diet and exercise, dysbiosis and infection, hormonal imbalances, immune dysfunction, GI dysmotility, and stress.

Top Functional Medicine Labs Used for GI Complaints

Functional medicine providers will commonly use specialty labs to help diagnose the root cause of GI symptoms. The results from these tests help practitioners personalize treatment protocols. Below are some of the most commonly used GI labs used in functional medicine:

Comprehensive Stool Test

Comprehensive stool tests are useful for assessing gut health, especially for those experiencing chronic pain associated with gastrointestinal issues. Imbalances in the microbiome and inflammation can lead to gastrointestinal symptoms such as bloating, abdominal pain, and irregular bowel movements. These tests analyze various markers of gastrointestinal health, including digestion and absorption, inflammation, potential immune dysfunction, imbalances in the microbiome, parasite infections, leaky gut markers (like zonulin), and many also test for overgrowth of candida.

Food Sensitivity Testing

Food sensitivity symptoms can easily overlap with other common medical diagnoses. Therefore, it’s vital to rule these sensitivities out while looking for a root cause. The most common symptoms associated with food sensitivities are gastrointestinal complaints. Based on the results of the testing, practitioners can personalize an elimination diet for patients to help alleviate gi disorders.

Candida Testing

Candida can overgrow for many reasons, but one of the most common reasons is dysbiosis (unbalance of the good vs bad gut bacteria). The health of your digestive system relies heavily on the good bacteria that live in your gut to keep bad bacteria and fungi in check. Once your gut microbiome is disrupted, candida can quickly multiply causing multiple different digestive problems.

Many comprehensive stool tests will test for Candida Albicans overgrowth and help rule out possible reasons for the candida overgrowth, such as dysbiosis or inflammatory markers leading to other health-related illnesses caused by the candida. Retesting a few months into care allows for any modification that may be needed.

SIBO Testing

Small intestinal bacterial overgrowth (SIBO) is a debilitating condition that can affect up to 80% of patients with IBS.

Over time SIBO can lead to chronic inflammation & immune conditions and could be putting you at risk for other ailments, including poor absorption of food and nutrients.

SIBO breath testing is a noninvasive testing alternative to small intestinal culture to diagnose SIBO and IMO. A SIBO breath test is performed the morning after a patient follows a restrictive preparatory diet and overnight fast.

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Functional Medicine Alternatives for Natural Treatment of GI Symptoms

Many patients seek integrative care after a conventional approach to treatment has resulted in unsatisfactory results. Below are common recommendations provided by functional medicine doctors to alleviate GI symptoms naturally without pharmacotherapy.

Nutrition and Diet Considerations for Improvement of GI Symptoms

Functional medicine doctors will often first turn to optimizing the diet when addressing chronic GI symptoms, understanding that diet influences GI inflammation and the microbiome's health. By shifting away from Western dietary patterns and towards an anti-inflammatory, whole-food diet (like the Mediterranean diet), we can increase the intake of fiber, phytonutrients, vitamins, and minerals known to repair the gut barrier and feed the healthy intestinal flora (18).

Alcohol and processed sugars are also known to disrupt gut barrier function, impair immune function, and induce negative changes to the balance of the gut microbiota. Abstaining from alcohol and minimizing refined sugars lowers the risk of chronic digestive disorders and reduces intestinal inflammation.

Functional medicine doctors recommend eating 25-35 grams of dietary fiber, but the average American dietary fiber intake is only 17 grams daily. Increasing dietary intake of both soluble and insoluble fiber is imperative for healthy gut function. High-fiber foods include vegetables, legumes, whole fruits, nuts, seeds, and whole grains. (19)

Supplemental and Herbal Alternatives for GI Symptoms

Deglycyrrhizinated Licorice (DGL) for Heartburn

Standard over-the-counter and pharmaceutical treatment options for heartburn include antacids, H2 blockers, and proton pump inhibitors. Side effects of these medications include digestive symptoms, headaches, nutrient deficiencies, and increased risk of infection.

Licorice (Glycyrrhiza glabra) root is a soothing anti-inflammatory herb. The whole root contains glycyrrhizin, which can cause elevations in blood pressure. DGL is a prepared form of the herb that does not have glycyrrhizin and is commonly used to treat heartburn, GERD, and gastritis. DGL promotes mucus activity, which acts as a barrier to acid in the upper digestive tract to heal damaged tissues and prevent future irritation to the tissues. Research supports that DGL is more effective than acid-suppressive drugs in treating gastritis and GERD. (1, 2)

Peppermint Oil for Abdominal Pain

Antispasmodics and antidepressants are routinely prescribed in managing irritable bowel syndrome (IBS)-related abdominal pain (3). Peppermint has traditionally been used to treat pain associated with various conditions, including headaches, IBS, and non-ulcer dyspepsia, because of its ability to induce smooth muscle relaxation. Many studies support the use of enteric-coated peppermint oil in treating IBS-related abdominal pain; in fact, the American College of Gastroenterology (ACG) has updated its IBS treatment recommendations to include peppermint oil as a first-line treatment option for abdominal pain. (4)

Ginger for Bloating

Bloating is the sensation of abdominal fullness and tightness, often accompanied by abdominal distension. Often, bloating is caused by increased intestinal gas production and slowed intestinal motility, resulting in trapped gas. Along with dietary modifications, simethicone, antacids, and antidepressants may be recommended as pharmaceutical agents to treat bloating.

Ginger (Zingiber officinale) has proven anti-inflammatory, anti-nausea, and prokinetic effects, among many others, that qualify its use for various GI-related conditions and symptoms. Rich in terpenes, phenolic compounds, and volatile oils, ginger acts in the digestive tract to coordinate gastrointestinal muscle contractions and increase gastric emptying, reducing flatulence and bloating. (5)

Magnesium for Constipation

Constipation may be a symptom of magnesium deficiency. As an alternative to laxatives, magnesium, most commonly supplemented in citrate or oxide forms, relaxes gastrointestinal smooth muscles and pulls water into the intestines. The net effect of magnesium supplementation is softening stool and promoting fecal transit. (6)

Saccharomyces boulardii for Diarrhea

Saccharomyces boulardii (Saccharo-B) is a probiotic yeast that improves gut barrier function, eradicates gut pathogens, and reduces inflammation. There is a large pool of evidence to support the use of Saccharo-B in the treatment of a variety of inflammatory and non-inflammatory diarrheal conditions, including IBS, traveler's diarrhea, antibiotic-associated diarrhea, and inflammatory bowel disease (IBD). (7-10)

Complementary and Integrative Medicine (CIM) for GI Symptoms

It can be easily overlooked, but lifestyle habits, including sleep hygiene and stress management, profoundly impact gut health and function. CIM modalities targeting the gut-brain axis can significantly influence GI health. Research suggests optimizing sleep can positively impact gut microbiome diversity and composition; healthy adults need at least seven hours of sleep nightly. Similarly, increased stress influences gut function; vagus nerve stimulation exercises can promote healthy stress responses, digestive function, and intestinal motility.

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Summary

Gastrointestinal symptoms and diseases affect an overwhelmingly large percentage of the population, contributing to decreased quality of life and economic burden related to healthcare costs. While conventional treatment options manage symptoms, they rarely address underlying causes of symptomology, and many pharmacologic agents can cause secondary GI symptoms. A functional medicine approach offers in-depth testing to uncover the root cause mechanisms of symptoms. Natural herbs and supplements can replace palliative medications as safe and effective alternatives, and many provide the additional benefit of addressing and correcting imbalances contributing to disease states.