Nutrition for Irritable Bowel Syndrome

Introduction

Irritable bowel syndrome (IBS) is characterized by chronic and/or recurrent abdominal pain or discomfort and altered bowel habits. A large number of patients with functional GI disorders, especially patients with irritable bowel syndrome and functional dyspepsia, complain that certain types of food exacerbate their symptoms.

Others complain that any type of food, even a sip of water, may trigger symptoms. Perceived food sensitivity may be related to a variety of factors, including conditioned fear responses related to anticipatory anxiety, food intake in general, volume of the meal, or sensitivities to certain food items. For example, insoluble bran fiber commonly exacerbates symptoms, but soluble fiber in the form of psyllium husk is often beneficial. A diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) can effectively reduce irritable bowel symptoms in some patients "see table 1". Preliminary data suggest that dietary glutamine supplementation (5 g three times daily for 8 weeks) supplementation can help restore normal intestinal permeability and reduce post-infectious irritable bowel diarrhea. Some patients with irritable bowel syndrome report an exacerbation of symptoms with high-fat food, dairy products, gas-producing food, gluten-containing food, alcohol, and caffeine. It is important to inform the patient that there is no universal diet for long-term improvement of symptoms.

Read diet plan for irritable bowel syndrome, available at: https://www.planetayurveda.com/library/diet-plan-for-irritable-bowel-syndrome

Table (1). Some common food sources of FODMAPs
Food Type	Free Fructose	Lactose	Fructans	Galacto-oligosaccharides	Polyols
Fruits	Apple, cherry, mango, pear, watermelon		Peach, persimmon, watermelon		Apple, apricot, pear, avocado, blackberries, cherry, nectarine, plum, prune
Vegetables	Asparagus, artichokes, sugar snap peas		Artichokes, beetroot, Brussels sprout, chicory, fennel, garlic, leek, onion, peas		Cauliflower, mushroom, snow peas
Grains and cereals			Wheat, rye, barley
Nuts and seeds			Pistachios
Milk and milk products		Milk, yogurt, ice cream, custard, soft cheeses
Legumes			Legumes, lentils, chickpeas	Legumes, chickpeas, lentils
Other	Honey, high-fructose corn syrup		Chicory drinks
Food additives			Inulin, FOS		Sorbitol, mannitol, maltitol, xylitol, isomalt
Abbreviations: FODMAPs, fermentable oligosaccharides, disaccharides, monosaccharides, and polyols; FOS, fructo-oligosaccharides. Source: Adapted from PR Gibson et al: Am J Gastroenterol 107:657, 2012.

Dietary considerations in IBS

Manage milder IBS symptoms or flares with dietary modifications such as avoiding foods that worsen symptoms. Avoidance of foods should be individualized. Foods that lead to or worsen symptoms can vary greatly from person to person. Suggest patients use a food diary to identify their triggers. Examples of common foods triggers include...

• Incompletely absorbed carbohydrates (e.g., dairy, beans/lentils, apples, flour).
• Foods rich in biogenic amines (e.g., wine, beer, processed meats, cheese).
• Histamine-releasing foods (e.g., milk, wine, beer, pork).
• Fried and fatty foods.

Recommend a trial of a low-FODMAP diet "see table 1" to decrease symptoms of IBS (suggestion per Canadian guidelines). FODMAPs (Fermentable Oligo-, Di-, and Monosaccharides And Polyols) are incompletely absorbed in the small intestine and fermented in the colon. FODMAPs include foods with...

• Fructose (e.g., apples, pears, honey, high-fructose corn syrup).
• Lactose (e.g., milk), consider lactose intolerance, especially in patients with IBS-Diarrhea.
• Fructans or galactans (e.g., beans, wheat, onions).
• Polyols (e.g., some fruits and vegetables, artificial sweeteners such as sorbitol).

Gluten restriction may lead to improvement in some patients with IBS. Test patients with IBS-Diarrhea for celiac disease (e.g., serological screening with immunoglobulin A [IgA] tissue transglutaminase and a quantitative IgA level). Celiac disease, an immune reaction to gluten, involves symptoms which can mimic IBS. Data suggest patients with IBS are at increased risk of celiac disease.

Role of fiber in patients with IBS

Goal fiber intake for all patients with IBS should be about 25 to 35 grams of fiber per day. Follow the motto, “start low and go slow,” when introducing fiber into the diet to increase the likelihood of tolerability. The benefits of fiber in IBS are limited to soluble fiber (e.g., fiber supplements, certain foods).

• Soluble fiber includes foods such as oats, barley, oranges, dried beans, and lentils.
• Avoid insoluble fiber (e.g., wheat brain, whole grains, some raw vegetables). Insoluble fiber can cause bloating and abdominal discomfort and should be avoided.

Soluble fiber seems to improve global symptoms (e.g., abdominal pain, stool consistency, IBS quality of life), especially in patients with IBS-Constipation. However, fiber may exacerbate other symptoms for some patients, especially bloating and flatulence.

Dietary ADVICE

1. Eat regularly and take time to eat.
2. Drink ≥ 8 cups of fluid daily, especially water or other noncaffeinated drinks.
3. Limit tea and coffee to ≤ 3 cups daily.
4. Reduce consumption of alcoholic and carbonated beverages.
5. Limit high-fiber foods such as whole grain breads, cereals high in bran, and whole grains such as brown rice.
6. Reduce consumption of ‘resistant starch’ (starch that resists digestion in the small intestine and reaches the colon intact), which is often found in processed or recooked foods.
7. Limit fresh fruit intake to < 240 g daily.
8. People with gas and bloating may find it helpful to incorporate oats and linseeds (up to 1 tablespoon per day) in their diet.
9. People with diarrhea should avoid sorbitol such as found in chewing gum.

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References

1. Lacy BE, Pimentel M, Brenner DM, Chey WD, Keefer LA, Long MD, Moshiree B. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol. 2021 Jan 1;116(1):17-44.
2. Moayyedi P, Andrews CN, et al. Canadian Association of Gastroenterology Clinical Practice Guideline for the Management of Irritable Bowel Syndrome (IBS). J Can Assoc Gastroenterol. 2019 Apr;2(1):6-29.
3. Khan MA, Nusrat S, Khan MI, Nawras A, Bielefeldt K. Low-FODMAP Diet for Irritable Bowel Syndrome: Is It Ready for Prime Time? Dig Dis Sci. 2015 May;60(5):1169-77.
4. Dietitians of Canada. Food sources of soluble fibre. March 16, 2012. https://carleton.ca/healthy-workplace/wp-content/uploads/soluble-fibre.pdf.
5. Wall GC, Bryant GA, Bottenberg MM, Maki ED, Miesner AR. Irritable bowel syndrome: a concise review of current treatment concepts. World J Gastroenterol. 2014 Jul 21;20(27):8796-806.

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