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IBS vs. IBD: Differentiating between disorders

Last Modified: October 06, 2021

Diseases & Disorders, Family Medicine


Their names may seem similar, but these chronic gastrointestinal diseases couldn’t be more different. Fortunately, we caught up with Vanessa Mendez, MD, PPG – Gastroenterology, and asked her to help define each disorder while offering some helpful pointers for those struggling with either condition.  

What are irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD)? 

Irritable Bowel Syndrome (IBS) is a prevalent disorder, impacting up to 45 million people in the United States alone. Although the exact causes are unknown, experts believe it results from a dysfunction in how the gut, nervous system and brain interact.

On the other hand, inflammatory bowel disease (IBD) is an umbrella term for four general types of chronic inflammatory disorders of the digestive tract. These are ulcerative colitis, Crohn’s disease and indeterminate colitis. Some experts also consider microscopic colitis to be part of the IBD spectrum. Furthermore, approximately 250 per 100,000 people in North America have some form of IBD. In 2015, that was roughly 1.3 million people in the U.S.

Are these two illnesses the same disease? 

No, these illnesses are not the same. Again, IBS is a dysfunction of how your brain and gut interact, causing a hypersensitive stomach, more prone to abdominal pain and cramping. It is also accompanied by an issue with your gut’s motility, meaning how fast or slow food moves through your system, which can result in diarrhea, constipation or both.

As for IBD, it has its own distinct attributes that aid in diagnosis. Those can include a loss of appetite, weight loss, fevers and rectal bleeding, which can lead to anemia. IBD is also generally characterized by inflammation and ulcerations in part of your digestive system. When looking at the colon, we often see signs of that chronic inflammation in the form of ulcers, fistulas, scarring, strictures and fissures. Additionally, IBD can be quite aggressive and, in some cases, require surgery.

What are the similarities in signs and symptoms of IBS and IBD? 

While IBS and IBD are not the same conditions, they do share some commonalities. The most common symptoms can include:

What are the leading causes of IBS and IBD? 

The causes of both these disorders are unknown, though there are some theories. Let’s explore each one a little further:


While the exact cause of IBS is unknown, one group of studies suggest it may be due to a history of foodborne illness, especially among women. Other studies indicate that it’s linked to an unhealthy or unbalanced gut microbiome. There’s also a possibility that both are true, as infectious gastroenteritis can lead to a disrupted microbiome. 


The causes of IBD are unclear. But the disorder is believed to be caused by a combination of genetic predisposition and various environmental factors that have a deleterious effect on intestinal microflora. This effect, in turn, causes an abnormal immune response throughout the host, resulting in chronic inflammation and ulceration in the gut.

What are the treatments for each digestive disorder? 

IBS is managed primarily through lifestyle changes to control symptoms. This can include diet modification (eliminating or reducing symptom-provoking foods), lowering stress levels and taking medications to help reduce the worst symptoms.  

With IBD, the goal of treatment is to reduce the inflammation that triggers symptoms and induce endoscopic remission. This is done through several medications, including:

  • Corticosteroids: Used in the short term to reduce acute inflammation
  • Aminosalicylates: Typically utilized with ulcerative colitis patients
  • Broad-spectrum antibiotics: Employed only as a supplemental therapy during flares of colonic Crohn’s disease, Crohn’s disease that’s unresponsive to other medical treatment, severe ulcerative colitis and with patients who had severe side effects from other medications
  • Immunomodulators: Applied in some cases to help reduce the steroid dosage needed and maintain disease remission
  • Biologic therapy: An injection or infusion in patients who have not responded to conventional treatment or in moderate to severe cases  
Can someone’s diet affect either condition?

Western diets high in animal protein and fat but low in fruit, vegetables and fiber-rich foods have been associated with IBD onset. However, studies show that more plant-forward and whole-food regimens like vegan, vegetarian and Mediterranean diets in conjunction with medical therapy have higher remission rates from IBD. Israel, Japan, and more recently, the U.S. have all studied the benefits of these plant-forward diets.

Is there a cure for either IBS or IBD?

There is no known cure for IBS or IBD. However, IBS symptoms can be managed and reduced with lifestyle changes and medication. Studies also showed that people who consume a diet high in fiber and low in processed foods and red or processed meats have a significantly decreased likelihood of developing IBD.

What advice would you give people dealing with either condition? 
  • Seek the help of a gastroenterologist as soon as possible! Getting the proper diagnosis is the first step in understanding your disease and coming up with a treatment plan. Many people are scared to get diagnosed or dismiss their symptoms as not severe enough, but this can result in possibly irreversible damage to your bowel. 
  • Discuss all your questions and concerns with your doctor. Finding someone who listens and addresses your problems and fears will be reassuring and put you at ease.
  • Learn what foods aggravate your condition. Keep a diary of when you have symptoms and what foods seem to trigger them. It should have three columns: one for your symptom flares, one for what you’ve eaten in the past 24 hours and one that details your stress levels or emotional state. This will help you decide what to avoid while helping reduce the number of times you experience a flare-up.
  • Eat quality food. Pay close attention to the types of foods you’re eating. Ensuring that you’re consuming a variety of fruits, vegetables, grains, legumes and nuts can help populate your microbiome with beneficial bacteria. This action will help improve your microbiome health and the gut-brain connection. Also, when possible, always use fresh and healthy ingredients while cooking and avoid consuming too much dairy, fatty and processed foods. If you have an intolerance to some of these items, be sure to discuss some strategies with your GI provider to help you tolerate them better.
  • Reduce your stress. Stress is a significant contributor to worsening gut health symptoms, so managing it can better help you cope with your chronic illness. There are many different relaxation and stress management techniques out there to help you cope with digestive symptoms. Don’t be afraid to try them.

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