Patient - Irritable Bowel Syndrome (IBS) Diet and Nutrition

• Agazzi A, De Ponti F, De Giorgio R, et al. "Review of the implications of dietary tryptophan intake in patients with irritable bowel syndrome and psychiatric disorders." Digestive and Liver Disease." 35:590-595, 2003.

  In this review, the possible role of the essential amino acid L-tryptophan or 5-hydroxytryptophan in the production of serotonin (a neurotransmitter) is addressed as well as its role in affecting certain central and peripheral nervous system disorders, including depression and irritable bowel syndrome. L-Tryptophan may represent a link between apparently different functional disorders. On the basis of estimates showing that approximately 20% of patients with functional bowel disorders seeking care also have psychological symptoms, an attempt is made to provide a conceptual framework for defining the possible role of L-tryptophan in this population.

• Alper BS.  "Evidence-based medicine. Antibody-guided food elimination may reduce symptoms of IBS."  Clinical Advisor. 8(2): 122, 2005.

  This article comments on a 12-week study with 150 patients with IBS who were tested for immunoglobulin (Ig)G antibodies against 29 different foods. One group was advised to follow a diet that eliminated all foods for which they tested positive (most commonly yeast, milk, whole eggs, wheat, cashew nuts and peas). The control group was advised to eat a diet that eliminated the same number of foods, but foods for which they did not have IgG antibodies (sham diet). The antibody-based elimination diet reduced IBS symptoms 38.5 points overall on a 500-point scale and by 98 more points in those who fully followed the diet. Using the outcome of improved global rating, responses were 28% in the elimination diet vs. 17% in those who were on the sham diet; and 54% vs. 15% in those who fully followed the diet. When eliminated foods were reintroduced into the diet, they led to greater worsening of symptoms in the true-diet group compared with the sham-diet group.

• Bijkerk CJ, de Wit NJ, Muris JW, et al. Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial. BMJ 2009; 339:b3154

  This randomized controlled trial examines the effectiveness of increasing the dietary content of soluble fiber (psyllium) or insoluble fiber (bran) in patients with IBS. 275 patients aged 18-65 years received 12 weeks of treatment with either 10 grams of psyllium, 10 grams of bran, or 10 grams of a placebo (rice flour). Symptom severity decreased the most in the psyllium group (by 90 points), compared with the placebo group (49 points) and the bran group (58 points) after three months. Results indicate that bran worsens symptoms of irritable bowel syndrome while psyllium offers benefits.

• Dear KL, Elia M,  Hunter JO. "Do interventions which reduce colonic bacterial fermentation improve symptoms of irritable bowel syndrome?" Digestive Diseases & Sciences. 50(4):758-66, 2005.

  This study assessed the relationship between IBS symptoms and fermentation rates in the colon. Subjects used either a standard diet, a standard diet with the antibiotic metronidazole, or a fiber-free diet to reduce fermentation. Both metronidazole and a no-fiber diet significantly reduce total gas and improved abdominal symptoms. The study indicated that IBS may be associated with rapid excretion of gaseous products of fermentation and when this is reduced IBS symptoms may improve.

• Eswaran S. Tack J. Chey WD. Food: the forgotten factor in the irritable bowel syndrome. Gastroenterology Clinics of North America. 40(1):141-62, 2011.

  There is a growing body of evidence to suggest that dietary constituents at least exacerbate symptoms and perhaps contribute to the development of the irritable bowel syndrome (IBS). While the evidence suggests that true food allergies are relatively uncommon, less clearly defined food intolerances may be an important contributor to symptoms in IBS patients. This article reviews the literature supporting a causal link between food and the symptoms of IBS as well as the evidence supporting dietary interventions as a way of managing IBS symptoms.

• Heizer WD, Southern S, McGovern S. The role of diet in symptoms of irritable bowel syndrome in adults: a narrative review. J Am Diet Assoc. 109(7):1204-14, 2009.

  This article reviews what is known about the effect of diet on irritable bowel syndrome (IBS) symptoms emphasizing data from randomized, controlled clinical trials. Results indicate that IBS symptoms in one quarter of patients may be caused or exacerbated by one or more dietary components, although it is very difficult to establish that a patient's symptoms result from an adverse reaction to food. Recent studies indicate that a diet restricted in fermentable, poorly absorbed carbohydrates, and other sugar alcohols is beneficial. Patients with IBS, especially those with constipation, may improve with increased intake of soluble fiber although insoluble fiber may worsen symptoms. In addition, daily use of peppermint oil is effective in relieving IBS symptoms.

• Floch MH. "Use of diet and probiotic therapy in the irritable bowel syndrome: analysis of the literature." Journal of Clinical Gastroenterology. 39(5 Suppl):S243-6, 2005.

  This report reviews the use of diet and probiotics in patients with irritable bowel syndrome (IBS) in published reports. Dietary factors can be important in inducing symptoms that occur in patients with the IBS. Dietary intolerances, dietary allergies, specific food metabolites, and regular diet contents all may act as triggers and aggravate the symptoms of IBS. If proven to cause IBS symptoms, their elimination can result in the resolution of that patient's IBS. The most common dietary factor evaluated in this review was bran, and the most common probiotic used was Lactobacillus plantarum. Although investigations have shown that bran may be helpful in some patients, a complete review of the literature does not reveal conclusive evidence that diet therapy is effective in IBS. From the limited reports on probiotics, there appears to be a trend to decreasing symptoms. Much more research is needed to study both dietary factors and probiotics in these areas.

• Floch MH, Narayan R. "Diet in the irritable bowel syndrome. Journal of Clinical Gastroenterology. 35(1 Suppl): S45-52, 2002.

  Present national dietary guidelines for people with IBS recommend dietary treatment with fiber for IBS patients with constipation. Diet recommendations are made based on symptoms and may differ by predominant symptom such as constipation, diarrhea, and pain or bloating. This article reviews the relationship of foods to IBS, discusses food intolerances and hypersensitivities, and provides recommendations for diet therapy. The role of dietary fiber, both soluble and insoluble, is reviewed as are the use of probiotics and prebiotics for IBS. Few studies substantiate exact diets, but broad dietary strategies can be recommended for different IBS symptoms.

• Lea R. Whorwell PJ. "The role of food intolerance in irritable bowel syndrome." Gastroenterology Clinics of North America. 34(2):247-55, 2005.

  Irritable bowel syndrome patients frequently believe that food intolerances are to blame for many of their symptoms, although not uncommonly this is caused by the nonspecific increase in gut motility that occurs with food ingestion. Nevertheless, dietary manipulation may result in substantial improvement in IBS symptoms if it is individualized to the particular patient. By further understanding the mechanisms involved in dietary intolerance, it should be possible to optimize the benefits of this approach to treatment.

• Mozaffari S, Rahimi R, Abdollahi M. Implications of melatonin therapy in irritable bowel syndrome: a systematic review. Current Pharmaceutical Design. 16(33):3646-55, 2010.

  Eight clinical trials were reviewed for effectiveness and disturbance of melatonin in IBS and other GI disorders. The results showed disturbances in melatonin concentration in patients with IBS and significant benefits of melatonin in these patients by decreasing abdominal pain and improvement of overall IBS symptom scores. The results of seventeen non-clinical studies showed anti-anxiety, anti-inflammatory, anti-oxidative and motility regulatory effects of melatonin on the GI tract. Melatonin is a target of interest in IBS because of its potentials to regulate GI motility.

• Santelmann H, Howard JM. "Yeast metabolic products, yeast antigens and yeasts as possible triggers for irritable bowel syndrome." European Journal of Gastroenterology & Hepatology. 17(1):21-6, 2005 Jan.

  This review looks at the possible involvement of Candida and yeasts in the development of IBS. While its role in the development of IBS is unclear, there is increasing evidence for yeasts being able to cause IBS-symptoms in sensitized patients. More research is needed, however, before antifungal treatment can be recommended as first line treatment for IBS.

• Zar S, Mincher L, Benson MJ, et al. "Food-specific IgG4 antibody-guided exlucsion diet improves symptoms and rectal compliance in irritable bowel syndrome." Scandinavian Journal of Gastroenterology. 40(7):800-7, 2005.

  Dietary modification may improve IBS symptoms. IgG4 antibodies to common food antigens are elevated in IBS with IgG4 antibodies to milk, eggs, wheat, beef, pork and lamb being the most common. This study evaluated the effect of an exclusion diet based on IgG4 titres on IBS symptoms. Twenty-five IBS patients who went on an exclusion diet showed significant improvement in IBS symptoms, including pain severity and frequency, bloating severity, satisfaction with bowel habits and effect of IBS on life in general at 3 months. Symptom improvement was maintained at six months.