Gastrointestinal Diseases: Types, Causes, and Symptoms

3.6.2025 0 comments

Author: Trisha Houghton, CNS, ASIST

The gastrointestinal tract (aka, digestive tract) is one of the hardest working of the internal systems.

It functions virtually around the clock, digesting the food you’ve eaten, absorbing nutrients, and processing waste materials for excretion.

Everything that you put in your body, both food and drink, drugs and medications, passes through your digestive system. What’s more, a significant amount of immune activity also takes place in your gastrointestinal tract (or, more commonly, the GI tract).

It’s no surprise, then, that given how hard-working the GI tract is, it is the source of some of the most common conditions and dysfunctions.

In this post, we’re going to take a closer look at the GI issues that affect so many people of all ages around the world.

We’ll look at what types of digestive diseases there are, what symptoms they manifest, and what causes them. 

Make sure to keep reading to the end where we’ll share some simple yet highly effective solutions for both preventing and reducing your risk of digestive issues. 

Introduction to Gastrointestinal (GI) Diseases

The digestive system is made up of a lot of hard-working parts, including:

• Your mouth and esophagus
• Your stomach
• Your large and small intestines
• Your liver 
• Your pancreas
• Your gallbladder

These parts work together to break down all the food you eat, starting in your mouth. They extract nutrients and water, then pass the remaining waste to the excretory system for elimination.

Gastrointestinal diseases refer to diseases or conditions that affect any part of your digestive tract from the mouth to the intestines. Some may be long-lasting (chronic), but many will last only a short time (acute).  

However, both acute and chronic GI disorders can have serious repercussions on your overall health.

Digestive tract diseases and disorders are often accompanied by painful and unpleasant symptoms, which can cause quite a great deal of discomfort in your daily life.

Anything that affects your digestive system also impacts its ability to process food and absorb nutrients. Reduced GI function can lead to an increased risk of nutrient deficiencies, and can affect your health on a body-wide scale.

As mentioned earlier, a large portion of your body’s immune activity occurs in the gut. Saliva, stomach acids, bile, digestive enzymes, and intestinal bacteria work together to neutralize harmful pathogens and microbes. If these defensive measures are impaired or affected negatively by a digestive disorder, the result may be a reduced immune response and greater risk of infection or illness.

Types of Gastrointestinal Diseases

There are a few common gastrointestinal diseases you need to know about and be on the lookout for.

Gastroesophageal Reflux Disease (GERD)

Gastroesophageal Reflux Disease, or GERD, is a condition that develops when acid reflux damages your upper digestive tract.

Acid reflux is a problem that occurs when the acidic contents of your stomach wash up your esophagus. It may be caused by overeating, eating spicy food, or eating a lot of fried food. It’s also a common side effect of pregnancy, heavy smoking, and obesity. 

However, it’s definitely the result of a weakened lower esophageal sphincter, the muscle-controlled opening that connects your esophagus to your stomach. 

Many cases of acid reflux are brief, occurring after greasy or spicy meals. However, long-term acid reflux, often caused by underlying digestive issues or consistently poor diet choices, can damage the esophagus.

Repeated exposure to stomach acid can erode the esophageal lining, a condition called esophagitis. This may cause burning chest pain, coughing, wheezing, difficulty swallowing, hoarseness, and a sore throat.

Left untreated, chronic acid reflux can lead to esophagitis, ulcers, or Barrett’s esophagus which elevates your risk of esophageal cancer.

Inflammatory Bowel Disease (IBD)

Inflammatory bowel diseases are diseases where any part of the bowels (the intestines) become inflamed. 

Two of the most common inflammatory bowel diseases are Crohn’s disease and ulcerative colitis.

• Crohn’s disease typically affects the lower end of the small intestines and the upper end of the large intestines. However, it can occur anywhere in the digestive system, starting at your mouth and ending at your rectum.
• Ulcerative colitis typically affects the colon lining and the rectum. It typically begins in the rectal area and can spread upward to the large intestines.

Both inflammatory conditions can be chronic and range from mild to severe. 

The exact cause of these conditions is unclear, but several factors can increase the risk. Genetics, immune system responses, and environmental influences all play a role (see the "Causes of Gastrointestinal Diseases" section below).

Symptoms may begin fairly minor, with abdominal pain and cramping, fatigue, diarrhea, and feelings of fullness in the intestines. However, they can grow serious, leading to fever, loss of appetite, weight loss, blood in your stool, pus or mucus around the rectum, ulcers, anal fistulas, external hemorrhoids, and pain and swelling in your joints. 

Ultimately, they may even become life threatening conditions. 

Irritable Bowel Syndrome (IBS)

Irritable Bowel Syndrome is a condition that affects the bowels, but is different from inflammatory bowel disease.

While the exact cause of IBS is not fully understood, it can result from factors including gut-brain interactions, stress, infections, and parasitic infections in the intestines.

IBS symptoms tend to be fairly mild initially, including gas, bloating, feelings of fullness, cramps, abdominal pain, and changes in your bowel habits (either diarrhea or constipation). 

However, if the condition persists, it can turn chronic (lasting more than three months, for at least three days each month). It can lead to blood in stools and weight loss, increasing your risk of nutrient deficiency at the same time. 

Peptic Ulcer Disease

Peptic ulcer disease is a condition characterized by ulcers (open sores or raw, tender flesh) in the lining of your intestines or stomach.

There are two types of peptic ulcers:

• Gastric ulcers in your stomach lining;
• Duodenal ulcers in the lining of your small intestines.

Peptic ulcers develop when the protective lining of the stomach and small intestine breaks down, allowing stomach acid to damage the underlying tissue.

Ulcers usually affect only the stomach or upper intestine lining. However, if they become severe, they can erode organ tissue, leading to abdominal bleeding. This condition, known as perforation, is a medical emergency requiring immediate care.

Ulcers are most commonly caused by infections of H. pylori bacteria, which break down the acid-resistant linings. However, excessive alcohol intake, heavy smoking or tobacco use, excessive or excessively frequent intake of NSAIDs, and chronic stress can all damage the stomach and intestinal linings and lead to ulcers. 

Ulcers manifest in the form of pain in your upper right abdomen, often at night but also when your stomach is empty. You may also experience nausea, bloating, feelings of fullness, chest pain, vomiting, fatigue, ongoing heartburn, and blood in your stool. 

Others

Other common types of gastrointestinal diseases include:

• Celiac Disease – An autoimmune disorder where the ingestion of gluten triggers an immune response, damaging the small intestine lining and leading to malabsorption of nutrients.
• Diverticulitis – Inflammation or infection of small pouches (diverticula) that can form in the walls of the colon, causing pain, fever, and digestive issues.
• Gastroparesis – A condition where the stomach muscles fail to properly move food into the small intestine, leading to bloating, nausea, vomiting, and delayed digestion.
• Hepatitis – Inflammation of the liver, often caused by viral infections (such as hepatitis A, B, or C), excessive alcohol use, or autoimmune conditions, affecting digestion and metabolism.
• Pancreatitis – Inflammation of the pancreas, leading to severe abdominal pain, nausea, vomiting, and impaired digestion due to reduced enzyme production.
• Gallstones (Cholelithiasis) – Hardened deposits of digestive fluids that form in the gallbladder, potentially blocking bile flow and causing pain, nausea, and digestive problems.
• Small Intestinal Bacterial Overgrowth (SIBO) – An overgrowth of bacteria in the small intestine that disrupts digestion, causing bloating, diarrhea, and malabsorption of nutrients.
• Lactose Intolerance – A digestive disorder where the body cannot properly digest lactose, leading to bloating, gas, and diarrhea after consuming dairy products.
• Hemorrhoids – Swollen veins in the lower rectum or anus that can cause pain, itching, and rectal bleeding, often related to constipation or straining during bowel movements.
• Colorectal Cancer – Cancer affecting the colon or rectum, often developing from polyps that become cancerous over time, leading to changes in bowel habits, blood in stool, and abdominal pain.

Knowing about these digestive diseases can help you spot symptoms early and get the right care. Simple habits like eating well, managing stress, and staying active can go a long way in keeping your gut healthy.

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Causes of Gastrointestinal Diseases

GI diseases typically take two forms:

• Functional gastrointestinal disorders
• Structural gastrointestinal disorders

Both types of gastrointestinal disorders have a number of causes that contribute to their development that you need to be aware of.

Genetic Factors

Genetics can predispose you to certain GI conditions, such as inflammatory bowel disease (IBD) and celiac disease. 

People with a family history of colorectal cancer are also more likely to develop colorectal cancer, and both ulcerative colitis and Crohn’s disease can be hereditary.

Lifestyle and Dietary Habits

Certain foods can increase your risk of gastrointestinal disease, including:

• Very spicy foods;
• Food heavy on potent spices;
• High-fat and fried foods;
• Processed foods.

Not only do these foods have the potential to affect the acidity of your stomach, but they can increase the probability of acid reflux and therefore increase the risk of ulcers.

Consuming a lot of food, or eating large meals late at night, can also contribute to GI problems (especially acid reflux, which can lead to GERD). 

Substance Use

Alcohol, tobacco, and long-term NSAID use (medications like ibuprofen or aspirin) can all contribute to higher risk of gastrointestinal problems, too.

They can alter your stomach acid content, irritate the digestive tract, leading to inflammation, ulcers, acid reflux, weaken the stomach lining and even impact your gut microbiome. 

Infections and Bacteria

Bacterial infections are a very common cause of gastrointestinal issues.

As you saw above, the H. pylori bacteria is the primary cause of peptic ulcers and can seriously damage the inner lining of your stomach and intestines. However, bacterial infections in your intestines can impair your gut microbiome and leave your intestines vulnerable to further infections that affect its function. 

And if infections persist, they can worsen inflammation, ulcers, impair nutrient absorption,contribute to gastritis and small intestinal bacterial overgrowth (SIBO) as well as  cause damage to the organ structures of your digestive tract, too. 

Immune System and Inflammation

Your immune system is often the culprit behind damage to your digestive tract.

Autoimmune disorders are conditions in which the immune system mistakes healthy tissue or cells as enemies and triggers a response—in the form of inflammation and white blood cells. 

Crohn’s disease and ulcerative colitis are both forms of Inflammatory Bowel Disease (IBD).They are autoimmune-related conditions that cause chronic inflammation in the digestive tract. 

Environmental and Socioeconomic Factors

People who lead high-stress lives are more prone to digestive dysfunction.

Those who live in areas with high pollution, low hygiene, and limited access to healthcare are also at risk. The combination of an increased strain on the digestive system and lack of medical and nutritional care can increase the probability of developing any number of gastrointestinal diseases.  

Symptoms of Gastrointestinal Diseases

The most common signs of gastrointestinal disease include the following symptoms:

• Nausea
• Bloating
• Altered bowel movements (diarrhea or constipation)
• Abdominal pain
• Fatigue
• Fever
• Bloody stool (a sign of more serious issues)

These GI symptoms may indicate something in your digestive tract requires further evaluation. 

However, there are some symptoms that will indicate specific GI conditions:

• Heartburn, acid regurgitation, sore throat, a chronic cough, and a hoarse voice can be symptoms  of GERD.
• Chronic diarrhea, unexplained weight loss, abdominal pain, and blood in the stool are common signs of IBD.
• Burning stomach pain, severe bloating, nausea, and in severe cases, bleeding can all point at peptic ulcers.

It’s important that you learn to recognize these symptoms in the early stages whenever possible. They’re your body’s way of telling you that something is malfunctioning or in need of treatment. 

The sooner you recognize the symptoms, the sooner you can take steps to manage the condition and prevent further damage or dysfunction. 

Prevention and Risk Reduction Strategies

There are a lot of ways that you can prevent or address gastrointestinal diseases, simple solutions that will drastically reduce the risk of damage to your digestive tract. 

Lifestyle and Dietary Modifications

The food you eat can have a huge impact on your digestive health. Eat the wrong food and you can increase the risk of damage, but eat right, and you’ll keep your GI tract functioning properly.

The best foods to eat are, you guessed it, rich in fiber—like veggies, fruits, whole grains, nuts, and seeds—will be excellent to improve your gastrointestinal health. However, some people with IBS or IBD may need to modify their fiber intake based on tolerance so be easy with yourself!

Make sure to drink plenty of water to facilitate nutrient absorption and waste elimination.

Reduce your intake of highly artificial and processed foods. Also, avoid foods that are very high in fat and fried or deep-fried.

Pay attention to what you eat and look for triggers. Even natural, otherwise healthy foods can cause digestive problems. For example, gluten can be an issue for those with celiac disease or non-celiac gluten intolerance, or tomato sauce can increase your risk of acid reflux.

If you see any specific foods or substances (including certain medications or supplements) that exacerbate symptoms, avoid them whenever possible.  

Regular Medical Check-ups and Screenings

While many of the GI tract issues we discussed above will present with visible symptoms—like pain, bloody stools, cramping, or bloating—some will present no symptoms until they grow serious.

For example, did you know that H. pylori bacteria is present in around 50 to 75% of the world’s population [1]? Most of the time, it can exist in your stomach without causing symptoms. However, it’s only when it begins to cause damage and erode your stomach or intestinal lining that you know it’s there.

Colon cancer is another condition that can exist and even spread through your intestines for a long time without your knowing it’s there.

Regular medical screenings and physical examinations are absolutely crucial to help you detect these conditions before they cause real damage. 

Stress Management and Mindful Eating

Chronic stress is one of the primary contributors to most health problems. It can cause inflammation, suppress your immune system, and so much more. In your GI tract, it can throw off your gut microbiome, increase stomach acid, elevate the risk of damage, and potentially worsen IBS and acid reflux.

Curbing stress is crucial for not only protecting your GI health, but the health of your entire body.

And definitely practice mindful eating! That means eating slowly, in moderation, and making smart, healthy choices that you know will benefit your body.  

Treatment and Management of Related Conditions

Conditions like obesity, diabetes, pancreatic issues, and bacterial infections can all lead to complications in the GI tract. Add those on top of lifestyle and diet factors, and you’ve got a significantly higher risk of digestive issues.

It’s important that you treat and manage any health conditions that could impair your digestive function before it causes problems in your stomach or intestines. 

Wrapping Up

Gastrointestinal diseases can be serious, but they don’t have to be.

With the proper care, lifestyle and diet choices, and regular medical check-ups and screenings, you can identify and address any issues before they become serious. 

When it comes to your digestive tract in particular, an ounce of prevention—in the form of healthy, mindful food choices and stress management—can be worth many pounds of cure!

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Frequently Asked Questions

How do I know if something is wrong with my digestive system?

Your digestive system will communicate the existence of dysfunction or structural gastrointestinal diseases through symptoms like pain, bloating, abdominal cramps, fever, fatigue, nausea, constipation, diarrhea, and bloody stool. However, frequent medical screenings and check-ups are recommended for early detection.  

What bowel symptoms should not be ignored?

Persistent diarrhea or constipation, persistent stomach pain, swallowing difficulties, unexpected weight loss, severe pain, bloody stools, and severe bloating or distention are all signs that something is seriously wrong with your bowels. 

What foods are hardest on the gut?

Alcohol, fried and deep-fried foods, spicy and spice-heavy foods, artificial sweeteners, and highly processed foods can irritate the r GI tract and trigger symptoms in people with sensitive GI systems.However, some people may struggle with gluten (gluten intolerance/celiac disease), dairy (lactose intolerance), or even vegetables. 

Resources

Digestive Diseases

Common Gastrointestinal (GI) Symptoms

Gastrointestinal Diseases

Digestive diseases

Digestive Disorders

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