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IBS vs. IBD: Understand the Differences, Similarities and Accurate Diagnosis

Updated: May 16, 2022




This is a common question among people who struggle with GI symptoms: is it IBS or is it something more? We need to ask ourselves this, because these two gastrointestinal illnesses have a handful of overlapping symptoms, but require different medications, nutritional plans, and lifestyle changes. It is important to get an accurate diagnosis.


Irritable bowel syndrome (IBS) is a functional disorder that affects the large intestine, but does not show inflammation upon screening/scoping. This means lifestyle modifications need to be made, but does not increase the risk of colorectal cancer. The precise cause of IBS is not known, but some factors that can play a role include:

  • Muscle contractions in the intestine. The walls of the intestines are lined with layers of muscle that contract as they move food through your digestive tract. Contractions that are stronger and last longer than normal can cause gas, bloating and diarrhea. Weak intestinal contractions can slow food passage and lead to hard, dry stools.

  • Nervous system. Abnormalities in the nerves in your digestive system may cause you to experience greater than normal discomfort when your abdomen stretches from gas or stool. Poorly coordinated signals between the brain and the intestines can cause your body to overreact to changes that normally occur in the digestive process, resulting in pain, diarrhea or constipation.

  • Severe infection. IBS can develop after a severe bout of diarrhea (gastroenteritis) caused by bacteria or a virus. IBS might also be associated with a surplus of bacteria in the intestines (bacterial overgrowth).

  • Early life stress. People exposed to stressful events, especially in childhood, tend to have more symptoms of IBS.

  • Changes in gut microbes. Examples include changes in bacteria, fungi and viruses, which normally reside in the intestines and play a key role in health. Research indicates that the microbes in people with IBS might differ from those in healthy people.

Additionally, you're more likely to have the syndrome if you:

  • Are young. IBS occurs more frequently in people under age 50.

  • Are female. In the United States, IBS is more common among women. Estrogen therapy before or after menopause also is a risk factor for IBS.

  • Have a family history of IBS. Genes may play a role, as many shared factors in a family's environment or a combination of genes and environment.

  • Have anxiety, depression or other mental health issues. A history of sexual, physical or emotional abuse also might be a risk factor.

Signs and symptoms include cramping, abdominal pain, bloating, gas, and diarrhea or constipation, or both, and bowel movement frequency.

Symptoms of IBS can be triggered by:

  • Food. The role of food allergy or intolerance in IBS isn't fully understood. A true food allergy rarely causes IBS. But many people have worse IBS symptoms when they eat or drink certain foods or beverages such as highly fermentable carbohydrates such as wheat, dairy products, beans, cabbage, milk and carbonated drinks, as well as high fructose fruits like apples and pears.

  • Stress. Most people with IBS experience worse or more-frequent signs and symptoms during periods of increased stress. But while stress may aggravate symptoms, it doesn't cause them.

Many people can control their symptoms by managing diet, lifestyle and stress. More-severe symptoms can be treated with medication and counseling. In addition to your primary care doctor and gastrointestinal specialist, referrals to a Registered Dietitian and/or Licensed Counselor Therapist is often beneficial.

Already know you have IBS? Here are some tips to deal with IBS.

Inflammatory bowel disease (IBD) is an umbrella term used to describe disorders that involve chronic inflammation of your digestive tract. Types of IBD include:

  • Ulcerative colitis. This condition involves inflammation and sores (ulcers) along the superficial lining of your large intestine (colon) and rectum.

  • Crohn's disease. This type of IBD is characterized by inflammation of the deeper lining of your digestive tract anywhere from the mouth to anus.

The exact cause of inflammatory bowel disease remains unknown. Risk factors for developing IBD include:

  • Age. Most people who develop IBD are diagnosed before they're 30 years old. But some people don't develop the disease until their 50s or 60s.

  • Race or ethnicity. Although caucasians have the highest risk of the disease, it can occur in any race.

  • Family history. You're at higher risk if you have a close relative — such as a parent, sibling or child — with the disease.

  • Cigarette smoking. Cigarette smoking is the most important controllable risk factor for developing Crohn's disease. Smoking may help prevent ulcerative colitis. However, its harm to overall health outweighs any benefit, and quitting smoking can improve the general health of your digestive tract, as well as provide many other health benefits.

  • Nonsteroidal anti-inflammatory medications. These include ibuprofen (Advil, Motrin IB, others), naproxen sodium (Aleve), diclofenac sodium and others. These medications may increase the risk of developing IBD or worsen the disease in people who have IBD.

Inflammatory bowel disease symptoms and the severity vary, depending on the severity of inflammation and where it occurs. It is common to have periods of active illness/flares followed by periods of remission. Signs and symptoms that are common to both Crohn's disease and ulcerative colitis include:

  • Diarrhea

  • Fatigue

  • Abdominal pain and cramping

  • Blood or mucus in your stool

  • Reduced appetite

  • Unintended weight loss

  • Joint Pain

  • Fever

  • Nutrition Deficiencies: iron, zinc, Vitamin B12, Vitamin D

Treatment for IBD includes pharmacologics, nutrition support, and surgery. An ideal team for IBD include your primary care physician, a gastrointestinal specialist, a Registered Dietitian, and a Licensed Counselor Therapist.



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