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Irritable Bowel Syndrome (IBS) Foods to Avoid and Eat

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Irritable Bowel Syndrome (IBS) Foods to Avoid and Eat

writtenByWritten by: Courtney Bennett
Courtney Bennett

Courtney Bennett

Courtney aims to simplify the complexities of modern medicine, enabling readers to make informed choices about their health. Her interests include reading, camping, hiking, painting, and photography.

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December 28, 2017 Read Time - 9 minutes

Irritable Bowel Syndrome (IBS) Foods to Avoid and Eat

American social culture often revolves around eating and drinking: dinner parties, happy hours, team lunches, catered networking events, and so on. Sufferers of irritable bowel syndrome not only have to deal with the unpleasant, uncomfortable symptoms of the disorder, we also must contend with the potential embarrassment of having an IBS flare up while at these social gatherings. Navigating the buffet line or hors d’oeuvres platters can feel akin to navigating a field of landmines.

For patients who have only recently uncovered a diagnosis of IBS, it can seem like there is no rhyme or reason to the causes of IBS. However, research by dietitians in recent years has led to the uncovering of certain foods that cause IBS symptoms in a majority of sufferers, as well as an elimination diet that can provide significant relief and a life changing guide to what to eat for IBS. Read on to learn about IBS, the FODMAP elimination diet, other IBS trigger foods, and foods that promote a healthy gut.

What is IBS?

Irritable Bowel Syndrome (IBS) is a chronic disorder that describes symptoms caused by the misfunctioning of the gastrointestinal tract. The symptoms and severity can vary wildly from person to person, with some people having episodes or flares followed by periods of remission, and some being afflicted by the symptoms daily. Rather than a clearly defined medical condition in and of itself, IBS is often called a diagnosis of exclusion. When other major diagnoses can be excluded (e.g. Chron’s or ulcerative colitis, celiac disease, gallstones) and no damage to the gastrointestinal tract is visible, IBS is often diagnosed.

IBS is generally classified as one of three categories:

  • IBS-C. IBS-C is primarily characterized by constipation.
  • IBS-D. IBS-D is primarily characterized by diarrhea.
  • IBS-M. IBS-M is characterized by a mix of both constipation and diarrhea. Sometimes also referred to as IBS-A.

Symptoms of IBS include:

  • Changes in motility (i.e. diarrhea and/or constipation)
  • Bloating / distention of the abdomen, especially after eating
  • Abdominal pain or cramps
  • Urgency
  • Mucus in stool
  • Feelings of incomplete emptying during bowel movements
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IBS Causes: An Evolving Landscape

The exact causes of IBS are unknown, and the condition itself is not well understood. Current understanding of the condition is that IBS is multifactorial, influenced by dysfunctions in the brain-gut communication axis caused by a combination of excess fermentation/gas production in the intestines, alterations in the gut microbiome, impaired transit of intestinal gas, increased visceral sensitivity, and genetic variations.

The Rome Foundation, a not-for-profit organization that supports the creation of scientific data and educational information in order to assist in the diagnosis and treatment of functional gastrointestinal disorders (FGIDs) came out with its fourth diagnostic manual in June 2016 (Rome IV). The manual says the following about the classification of functional gastrointestinal disorders: “Functional GI disorders are disorders of gut–brain interaction. It is a group of disorders classified by GI symptoms related to any combination of the following: motility disturbance, visceral hypersensitivity, altered mucosal and immune function, altered gut microbiota, and altered central nervous system processing.”

How is IBS Diagnosed?

There are no tests to confirm a diagnosis of IBS. Instead, a thorough medical history is often the first step toward a diagnosis. Depending on the severity of symptoms, a variety of tests may be done to confirm that there are no other, potentially life threatening, illnesses masquerading as IBS. These tests can include:

  • Endoscopy: used to identify the presence of ulcers, stomach cancer, or other abnormalities of the stomach and duodenum (the beginning of the small intestine)
  • Colonoscopy: can show any abnormalities of the large intestine, such as damage and inflammation related to Chron’s disease or ulcerative colitis, diverticulitis, or colon cancer
  • Gallbladder ultrasound: can confirm or deny the presence of gallstones
  • Celiac blood test: identifies whether a patient is allergic to gluten
  • Stool test: used to identify any abnormalities, such as blood, H. pylori (bacteria that causes ulcers), or improperly digested fat
  • Gastric emptying study: abnormal results can indicate gastroparesis, also known as delayed stomach motility or digestion
  • Hydrogen breath test: used by some physicians to diagnose small intestine bacterial overgrowth (SIBO) but many medical facilities do not perform this test since there is debate regarding standard hydrogen levels
  • Book on our free mobile app or website.

    Our doctors operate in all 50 states and same day appointments are available every 15 minutes.

  • See a doctor, get treatment and a prescription at your local pharmacy.

  • Use your health insurance just like you normally would to see your doctor.


FODMAPs and the Elimination Diet

Many IBS sufferers find that avoiding some or most FODMAPs in their diet provides them with significant relief from their symptoms. FODMAPs stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols. These are short chain carbohydrates and sugar alcohols that are generally poorly digested and absorbed by the gastrointestinal tract. These molecules act as fast food to the bacteria that live within your intestines – the bacteria rapidly break down (ferment) the undigested material, which leads to the uncomfortable symptoms that accompany IBS.

  • Oligosaccharides – Oligosaccharides are molecules made up of multiple sugars. These include fructans and galacto-oligosaccharides (GOS), most commonly found in garlic, onions, wheat, rye, and beans.
  • Disaccharides – Disaccharide are double sugar molecules. This includes lactose, most commonly found in dairy products such as milk and yogurt.
  • Monosaccharides – Monosaccharides are single sugar molecule. This includes fructose, which is found in many fruits, honey, and especially in high fructose corn syrup.
  • Polyols – Polyols are sugar alcohols. These include sorbitol, mannitol, maltitol, xylitol, and isomalt, which are found in certain fruits and are used as artificial sweeteners in products such as sugar-free gum.

This information was originally discovered by a research team at Monash University in Melbourne, Australia and has gained wide popularity among IBS sufferers. The elimination diet is done in two phases:

  • Phase 1: All high FODMAP foods are restricted for 4 to 6 weeks. It is recommended that you consult with a dietitian to ensure you are still getting an adequate amount of nutrition during this phase. It is important for you to keep track of any symptom changes or improvements during this period.
  • Phase 2: During this phase, each category of FODMAP is gradually reintroduced one at a time. Your dietitian may recommend a specific order to do the elimination diet in, otherwise you can choose whichever order you would like. When reintroducing a food group, you should begin with a small amount (e.g. add dairy to one meal), and work your way to whatever a “normal” amount of that category would be for you (e.g. if you would normally have milk with every meal and have ice cream for dessert, you should work up to this amount). The goal is to find the level at which each FODMAP can be tolerated in order to create the least restrictive long term diet possible. A detailed journal should be kept during this phase in order to document symptoms. Before you move on to the next FODMAP category, you need to return to phase 1 for one week in order to re-establish a symptom free baseline.

It is important to note that, while the FODMAP elimination diet produces life changing results for many IBS sufferers, it is not universal and some patients do not see their symptoms improve.

Other IBS Trigger Foods

In addition to the high FODMAP foods described above, there are several other triggers that may aggravate IBS symptoms, including:

  • Spicy foods – foods that are heavily spiced, especially with chili peppers that contain capsaicin, tend to irritate the stomach lining and contribute to IBS abdominal cramps and diarrhea.
  • Fatty, fried, or greasy foods – fats are one of the strongest stimulators of the gastrocolic reflex. The gastrocolic reflex controls peristalsis, which is the involuntary contraction of the intestines during the digestive process. For individuals who already have dysfunctional peristalsis, foods that are high in fat often increase the dysfunction of the contractions, and contribute to abdominal pain and changes in motility.
  • Alcohol – alcohol is a strong stimulant and irritant to the digestive tract. In addition, the carbonation that is found in beer tends to further irritate the stomach and contribute to the buildup of excess gas.
  • Coffee/ Caffeine – caffeine, especially consumed when drinking coffee, acts as a stimulant to the intestines and produces a well-known laxative effect. This can be particularly problematic for IBS-D sufferers. Caffeine also stimulates the nervous system, increases stress hormones, and acts as a diuretic – all of which can negatively affect digestion.
  • Soluble and insoluble Fiber – fiber is necessary as part of a healthy diet and can play a beneficial role in IBS management, but it can also greatly exacerbate symptoms, depending on the type of IBS that you have. Soluble fiber acts to slow down colonic transit times and allows for greater water absorption – this can be beneficial to IBS-D sufferers, while causing painful problems for IBS-C sufferers. Conversely, insoluble fiber acts to speed up colonic transit times, which can either improve constipation or worsen diarrhea.
  • Book on our free mobile app or website.

    Our doctors operate in all 50 states and same day appointments are available every 15 minutes.

  • See a doctor, get treatment and a prescription at your local pharmacy.

  • Use your health insurance just like you normally would to see your doctor.


Foods to Promote a Healthy Gut

Reviewing the list of foods you should remove from your diet can be daunting and leave you feeling like what food can you eat? While each person’s body is unique, some great foods to promote a healthy gut include:

  • Soluble and insoluble fiber – as described above, whether a certain fiber will be harmful or helpful to you personally depends on the type of IBS that you have. IBS-D sufferers should focus on increasing soluble fiber, while IBS-C sufferers should increase their intake of insoluble fiber, in order to help regulate dysfunctions in motility.
  • Fermented food – foods such as kimchi (fermented vegetables), sauerkraut (fermented cabbage), and yogurt (fermented milk) contain the bacteria Lactobacillus which produce lactic acid and are shown to improve the digestion of lactose and stimulate the gut immune system.
  • Probiotics – similar to eating fermented foods, taking probiotic supplements may contribute to a healthy, diverse gut microbiome and a reduction of IBS symptoms. However, it is important to note that long term symptom improvement have not been effectively proven. Additionally, since dietary supplements are not regulated as drugs in the United States, patients should carefully research any probiotic and their manufacturer before beginning treatment.
  • Water – staying well hydrated helps to promote a healthy gastrointestinal tract, as well as helping to combat constipation.

It is important to consult a physician for an accurate diagnosis before starting any treatment. Depending on the severity of your condition, you may require medication in addition to the diet modifications outlined in this article. If you or a loved one are experiencing IBS-like symptoms, you can make an appointment with your primary care physician or visit an urgent care center in order to be evaluated and diagnosed.

Read more from our IBS Series:

Most PlushCare articles are reviewed by M.D.s, Ph.Ds, N.P.s, nutritionists and other healthcare professionals. Click here to learn more and meet some of the professionals behind our blog. The PlushCare blog, or any linked materials are not intended and should not be construed as medical advice, nor is the information a substitute for professional medical expertise or treatment. For more information click here.

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