Young. Choi. ACG 68th Annual Scientific Meeting; Abstract 547, presented Oct. 14, 2003.

Summary: In the first study, Young K. Choi, MD, from the University of Iowa in Iowa City, and colleagues tested 80 patients with suspected IBS; 30 had positive fructose breath tests. The patients were taught to identify foods high in fructose and urged to avoid them.

While not as well known as lactose intolerance, fructose intolerance is common, with previous research by the same investigators showing it affects up to 58% of patients with symptoms of IBS.

After one year, 26 patients were available for a follow-up evaluation that included a structured interview to assess their dietary compliance and symptom patterns. Only 54% of participants reported that they remained on the fructose-restricted diet for a significant amount of time, Dr. Choi reported.

But those who remain on the fructose-restricted program reported significantly less abdominal pain, bloating, and diarrhea than before changing their diets (P < .05), he said. Noncompliant patients showed no improvement in symptoms.

On the ROME I scale, only 43% of patients who complied with the fructose-restricted diet continued to have symptoms of IBS compared with 75% of those who continued to eat fructose-rich foods.

Link: http://www.medscape.com/viewarticle/462955

Authors: Bohmer CJ, Tuynman HA.

Institution: Department of Gastroenterology, Academical Hospital Free University, Amsterdam, The Netherlands.

Objective: The prevalence of lactose malabsorption (LM) in the Caucasian population of northern Europe is estimated to be low. Irritable bowel syndrome (IBS) is a very common diagnosis, and its symptoms are nearly identical to those of LM. Therefore we investigated the prevalence of LM among IBS patients in comparison with healthy volunteers.

Results: In 17 out of 70 (24.3%) IBS patients LM was detected, in comparison with 2 out of 35 (5.7%) controls (P < 0.009). There was no difference in the pre-entry mean lactose intake and symptom score between the LM positive and negative IBS patients. The mean symptom score of the LM positive group showed a marked decrease after 6 weeks of dietary therapy (P < 0.001).

Conclusion: A substantial number of IBS patients showed a clinically unrecognized lactose malabsorption, which could not be discriminated by symptoms and dietary history, and which can be treated with a lactose-restricted diet. Therefore LM has to be excluded before the diagnosis IBS is made.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8930569&query_hl=23

Authors: Pimentel M, Chow EJ, Lin HC.

Institution: GI Motility Program, Department of Medicine, CSMC Burns and Allen Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.

Objective: We have recently found an association between abnormal lactulose breath test (LBT) findings and irritable bowel syndrome (IBS). The current study was designed to test the effect of antibiotic treatment for IBS in a double-blind fashion.

Methods: Consecutive IBS subjects underwent an LBT with the results blinded. All subjects were subsequently randomized into two treatment groups (neomycin or placebo). The prevalence of abnormal LBT was compared with a gender-matched control group. Seven days after completion of treatment, subjects returned for repeat LBT. A symptom questionnaire was administered on both days.

Results: After exclusion criteria were met, 111 IBS subjects (55 neomycin, 56 placebo) entered the study, with 84% having an abnormal LBT, compared with 20% in healthy controls (p < 0.01). In an intention-to-treat analysis of all 111 subjects, neomycin resulted in a 35.0% improvement in a composite score, compared with 11.4% for placebo (p < 0.05). Additionally, patients reported a percent bowel normalization of 35.3% after neomycin, compared with 13.9% for placebo (p < 0.001).

There was a graded response to treatment, such that the best outcome was observed if neomycin was successful in normalizing the LBT (75% improvement) (one-way ANOVA, p < 0.0001). LBT gas production was associated with IBS subgroup, such that methane excretion was 100% associated with constipation-predominant IBS. Methane excretors had a mean constipation severity of 4.1, compared with 2.3 in all other subjects (p < 0.001).

Conclusions: An abnormal LBT is common in subjects with IBS. Normalization of LBT with neomycin leads to a significant reduction in IBS symptoms. The type of gas seen on LBT is also associated with IBS subgroup.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12591062&query_hl=8

Authors: Bohmer CJ, Tuynman HA.

Institution: Department of Gastroenterology, Academic Hospital Vrije Universiteit, Amsterdam, The Netherlands. CJM.Bohmer@azvu.nl

Design and Methods: Prospectively, the effect of a lactose-restricted diet was evaluated among irritable bowel syndrome patients with lactose malabsorption. Lactose malabsorption was defined by a positive hydrogen breath test and a positive blood-glucose test. An analysis of symptoms was completed before, during, 6 weeks after and 5 years after starting the diet. In addition, the number of visits made by the patients to the outpatient clinic was scored during 6 years.

Results: In 17 out of 70 irritable bowel syndrome patients (24.3%), lactose malabsorption was detected. There was no difference in the symptom score between patients with a positive lactose tolerance test and patients with a negative lactose tolerance test. After 6 weeks of the lactose-restricted diet, symptoms were markedly improved in lactose malabsorption-positive patients (P < 0.001).

After 5 years, one patient was lost for follow-up, and 14 out of the remaining 16 lactose malabsorption patients (87.5%) still had no complaints during the lactose-restricted diet. Two patients chose not to follow the diet continuously and accepted the discomfort caused by lactose intake. Only two out of 16 patients (12.5%) no longer experienced any benefit from lactose restriction.

In the 5 years before their diagnosis of lactose malabsorption, these 16 patients visited the outpatient clinic a total of 192 times (mean 2.4 visits per year per person; range 1-7 visits). In the 5 years after diagnosis, they visited the outpatient clinic a total of 45 times (mean 0.6 visits per year per person; range 0-6 visits; P < 0.0001).

Conclusions: In a large majority of irritable bowel syndrome patients with lactose malabsorption, which was previously clinically unrecognized, a lactose-restricted diet improved symptoms markedly both in the short term and the long term. Furthermore, visits by all patients to the outpatient clinic were reduced by 75%. We conclude that diet therapy is extremely cost- and time-saving. Therefore, it is strongly recommended that lactose malabsorption, which is easily treatable, is excluded before diagnosing irritable bowel syndrome.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11507359&query_hl=6

Authors: Rana SV, Mandal AK, Kochhar R, Katyal R, Singh K.

Institution: Department of Superspeciality of Gastroenterology, Postgraduate Institute of Medical Education & Research, Chandigarh 160012, India. svrana25@hotmail.com

Background: Twenty-five patients of irritable bowel syndrome (IBS) and 25 normal healthy individuals serving as controls, were studied for lactose intolerance.

Methods: Hydrogen breath test was used as an investigation after giving 50 g of oral lactose. Clinically, the patients were classified into 3 types of IBS.

Results: Eleven (44%) out of 25 patients belonged to diarrhoeal type of IBS, 7 (28%) of 25 patients to spastic and rest 7 (28%) of 25 patients had features of both types of symptoms. Lactose hydrogen breath test was abnormal in 9 cases (82%) of 11 diarrhoeal type of IBS which was significantly higher (p < 0.02) than controls. However, the difference of abnormal hydrogen breath test between spastic type of IBS and patients with features of both types was not significant as compared to controls.

Conclusions: These results suggest that patients with diarrhoeal type of IBS have a higher incidence of lactose intolerance as compared to spastic type as well as patients with features of both types.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11963325&query_hl=1

Authors: Hebden JM, Blackshaw E, D'Amato M, Perkins AC, Spiller RC.

Institution: Department of Gastroenterology, University Hospital Nottingham, United Kingdom.

Objective: Bloating is an important but poorly understood symptom in irritable bowel syndrome (IBS) that is often aggravated by bran. The aim of our study was to determine whether IBS patients with bloating responded to bran differently from healthy controls.

Results: Results are given as median (range). Bran significantly increased the pain index and bloating (p < 0.02) in IBS patients but not controls. The most striking finding was that the small bowel transit time of the meal without bran was markedly faster in IBS patients than in controls, being 203 min (range 109-313) versus 367 min (219-543), p < 0.001. Although in controls bran accelerated small bowel transit time to 262 min (180-380), p = 0.03, and significantly reduced % remaining in the ascending colon from 22% (0-46) to 3% (0-25), p = 0.03, this was not seen in the IBS patients. Bran accelerated whole gut transit as assessed by geometric center at 24 h in both IBS patients and controls.

Conclusions: Bran accelerates small bowel transit and ascending colon clearance without causing symptoms in controls. Small bowel transit is rapid in IBS patients with bloating and, unlike in healthy control subjects, cannot be further accelerated by bran, which nevertheless aggravates symptoms of pain and bloating. We speculate that bran-induced bloating may originate in the colon rather than the small bowel.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12358250&query_hl=76

Authors: TH Vesa, LM Seppo, PR Marteau, T Sahi and R Korpela

Institution: Department of Biochemistry and Food Chemistry, University of Turku, Finland.

Summary: It has been suggested that the symptoms of irritable bowel syndrome (IBS) may be wrongly attributed to lactose intolerance. We examined the relations among IBS, demographic factors, living habits, and lactose intolerance. On the basis of a lactose tolerance test with ethanol, 101 of the 427 healthy subjects studied were lactose maldigesters and 326 were lactose digesters.

IBS was diagnosed by means of the Bowel Disease Questionnaire, according to the Rome criteria. The use of dairy products and symptoms experienced after their consumption were recorded. IBS was found in 15% of both the lactose maldigesters and lactose digesters. One-third of the subjects reported intolerance to dairy products containing < or = 20 g lactose. About half of this third were lactose maldigesters and about half were lactose digesters.

As explanations for this subjective lactose intolerance, the logistic regression model estimated lactose maldigestion (odds ratio: 10.3; 95% CI: 5.2, 20.4), IBS (4.6; 2.1, 10.1), experience of symptoms other than gastrointestinal ones (2.3; 1.2, 4.5), and female sex (2.1; 1.1, 4.0). Characteristics common to both subjective lactose intolerance and IBS were female sex and the experience of abdominal pain in childhood (P < 0.01). Age, regularity of meals, and the amount of physical activity were not associated with either subjective lactose intolerance or IBS.

Of the subjects with IBS, the percentage of lactose maldigesters was the same as in the whole study group (24%) but the number who reported lactose intolerance was higher (60% compared with 27%, P < 0.001). We showed a strong relation among subjective lactose intolerance, IBS, the experience of abdominal pain in childhood, and female sex.

Study link: http://www.ajcn.org/cgi/content/abstract/67/4/710

Authors: Vernia P, Di Camillo M, Marinaro V.

Institution: Chair of Gastroenterology 1, La Sapienza University, Rome, Italy. vernia@uniroma1.it

Background: The relationship between lactose malabsorption, irritable bowel syndrome and development of intestinal symptoms is unclear, especially when the ingested dose of milk is small.

Thus, the role of hydrogen breath testing in the diagnostic work-up of patients with nonspecific intestinal symptoms is still debated. AIMS: To establish the relationship between lactose malabsorption, severe self-reported milk intolerance, irritable bowel syndrome and related symptoms.

Results: The prevalence of a positive breath test was comparable in the two groups (337 patients with irritable bowel syndrome (66.9%) vs 240 patients with milk intolerance (71.4%)). The same holds true for the first peak of hydrogen excretion, total hydrogen output and prevalence of symptoms during, and in the four hours after, the test. The predominant presenting symptom was not useful for predicting outcome of the test either in regular milk users or in milk intolerant subjects.

Conclusions: The almost identical results of the lactose breath test of patients with irritable bowel syndrome and subjects with self-reported milk intolerance suggests that the two conditions overlap to such an extent that the clinical approach should be the same. A lactose breath test should always be included in the diagnostic work-up for irritable bowel syndrome, as fermentation of malabsorbed lactose is likely responsible for triggering symptoms. Conversely, lactase deficiency is probably irrelevant in most subjects not affected by irritable bowel syndrome, within a moderate milk consumption.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11407668&query_hl=50

Authors: Soltoft J, Krag B, Gudmand-Hoyer E, Kristensen E, Wulff HR.

Summary: 59 outpatients with irritable bowel syndrome participated in a randomised double-blind trial. The patients in the treatment group received three biscuits daily each containing 10 g of ordinary miller's bran, whereas the patients in the control group received wheat biscuits of a similar appearance.

The treatment period was 6 weeks. 52% of the patients in the treatment group noted subjective improvement compared with 65% in the control group.

The results of this trial do not support the routine use of miller's bran in irritable bowel syndrome.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=55586&query_hl=37

Authors: Simren M, Mansson A, Langkilde AM, Svedlund J, Abrahamsson H, Bengtsson U, Bjornsson ES.

Institution: Department of Internal Medicine, Section of Gastroenterology and Hepatology, Sahlgrenska University Hospital, Goteborg, Sweden. magnus.simren@medicine.gu.se

Background/Aims: Postprandial symptoms are common in patients with irritable bowel syndrome (IBS). However, existing studies have come to different conclusions about the role of food in the pathophysiology of IBS. We explored the prevalence of subjective food-related gastrointestinal (GI) symptoms and its relationship to clinical characteristics and psychological factors in IBS.

Methods: 330 patients with IBS and 80 healthy volunteers completed a food questionnaire developed for this study. The subjects graded their subjective symptoms after 35 different foods and a food score was obtained by adding the item scores. The relationship between subjective food-related GI symptoms and referral status, IBS subgroup (predominant bowel pattern), sex, anxiety, depression and body mass index (BMI) was estimated.

Conclusion: A majority of IBS patients consider their symptoms to be related to meals. Especially foods rich in carbohydrates and fat cause problems. Nevertheless, the majority of IBS patients are normal or overweight.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11244249&query_hl=35

Authors: Lewis MJ, Whorwell PJ.

Comment: The irritable gut is known to be hypersensitive, and it is reasonable to suspect that patients with the disorder might be hyperreactive to agents that stimulate or irritate it.

This appears to be a possible explanation for the adverse effects of bran on hospital patients with this disorder, but we do not yet know how this product affects community IBS sufferers. We cannot ignore the fact that fiber and bran have major beneficial effects in other areas, not least in the reduction of colonic carcinoma.

In conclusion, it is probably best to recommend that patients with IBS be left to judge for themselves whether bran helps or exacerbates their symptoms, but there is enough evidence to suggest that the current dogma of routinely treating all IBS sufferers with bran should be challenged.

Proprietary sources of fiber, such as ispaghula, may be more appropriate for those IBS subjects (for example, constipated) for whom fiber supplementation is believed justified.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9614316&query_hl=33

Authors: Symons P, Jones MP, Kellow JE.

Institution: Dept. of Medicine, Royal North Shore Hospital, Sydney, Australia.

Comment: The role of fructose and sorbitol, when ingested together, in the aetiology of irritable bowel syndrome (IBS) is controversial.

The aims of this study in IBS patients, therefore, were to compare differences in symptom provocation with various doses of fructose-sorbitol and to relate differences in the extent of colonic hydrogen production after each dose to such symptom provocation.

Two different mixtures of fructose and sorbitol--20 g fructose plus 3.5 g sorbitol ('lower' dose) and 25 g fructose plus 5 g sorbitol ('higher' dose)--were administered to 15 patients with IBS and to 24 healthy controls. Breath hydrogen concentrations were determined at 10-min intervals for 3 h after ingestion of each mixture, and the presence and severity of a range of gastrointestinal symptoms were recorded on a standard form before, during, and after the study.

Total symptom score in IBS patients, but not controls, was greater (p < 0.05) after the higher than after the lower dose of fructose-sorbitol mixture, and, for the higher dose, symptoms were significantly greater in IBS patients than in controls (p < 0.05).

Moreover, the increase in total symptom score between the higher and lower dose mixtures was of a greater magnitude (p = 0.01) in IBS patients than in controls…

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=1455191&query_hl=31

Authors: Rumessen JJ, Gudmand-Hoyer E.

Institution: Department of Gastroenterology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark.

Comment: Twenty-five patients with functional bowel disease were given fructose, sorbitol, fructose-sorbitol mixtures, and sucrose. The occurrence of malabsorption was evaluated by means of hydrogen breath tests and the gastrointestinal symptoms, if any, were recorded.

Based on a cut-off level of 10 ppm rise of H2 concentration, malabsorption was apparent in 13 patients, in 7 of which the calculated absorption capacities were below 15 g. In contrast, in patients given 50 g of sucrose, malabsorption could not be detected. Ingestion of fructose caused marked abdominal distress in patients with demonstrable malabsorption. Ingestion of sucrose in these patients gave less pronounced symptoms of abdominal distress. Malabsorption of a 5-g dose of sorbitol could be detected in 8 of 13 patients. Mixtures of 25 g of fructose and 5 g of sorbitol caused significantly increased abdominal distress, and more than additive malabsorption was found in several cases.

The present study shows that pronounced gastrointestinal distress may be provoked by malabsorption of small amounts of fructose, sorbitol, and fructose-sorbitol mixtures in patients with functional bowel disease.

The findings may have direct influence on the dietary guidance given to a major group of patients with functional bowel disease and may make it possible to define separate entities in this disease complex.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=3396816&query_hl=28

Authors: Fernandez-Banares F, Esteve-Pardo M, de Leon R, Humbert P, Cabre E, Llovet JM, Gassull MA.

Institution: Department of Gastroenterology, Hospital Universitari Germans Trias i Pujol, Badalona, Spain.

Objective: To investigate the relationship of sugar malabsorption to the development of clinical symptoms in functional bowel disease.

Results: Frequency of sugar malabsorption was high in both patients and controls, with malabsorption of at least one sugar in more than 90% of the subjects. Median symptom scores after both lactose [median 6; interquartile (IQ) range 3-7] and fructose plus sorbitol (median 2; IQ range 0-4) malabsorption were significantly higher than after sucrose load (median 1; IQ range 0-1.5) in functional bowel disease patients (p = 0.001 and p = 0.007, respectively).

However, there were no differences in healthy controls. In addition, symptoms score after both lactose and fructose plus sorbitol malabsorption was significantly higher in patients than in control subjects (p = 0.02 and p = 0.008, respectively)…

Conclusions: These results suggest that sugar malabsorption may be implicated in the development of abdominal distress in at least a subset of patients with functional bowel disease.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8249972&query_hl=12

Authors: Francis CY, Whorwell PJ.

Institution: Department of Medicine, University Hospital of South Manchester, UK.

This study questions whether conventional and traditional dietary advice to treat IBS – wheat bran consumption - is effective.

Comment: Whilst following up large numbers of patients with irritable bowel syndrome we got the impression that wholemeal wheat and bran products made people with the condition worse rather than better.

One hundred consecutive new referrals, all of whom had tried bran, were questioned to resolve this issue. 55% of patients were made worse by bran whereas only 10% had found it helpful. With the exception of fruit, other forms of dietary fibre were not as detrimental and proprietary supplements were found to be beneficial.

All symptoms of irritable bowel syndrome were exacerbated by bran, with bowel disturbance most often adversely affected, followed by abdominal distension and pain. The results of this study suggest that the use of bran in irritable bowel syndrome should be reconsidered.

The study also raises the possibility that excessive consumption of bran in the community may actually be creating patients with irritable bowel syndrome by exacerbating mild, non-complaining cases.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7912305&dopt=Abstract

Authors: Robert Goldstein PhD, Dan Braverman MD and Halina Stankiewicz MSc

Institution: Gastroenterology Institute, Shaare Zedek Medical Center, Jerusalem, Israel

Background: Carbohydrate malabsorption of lactose, fructose and sorbitol has already been described in normal volunteers and in patients with functional bowel complaints including irritable bowel syndrome. Elimination of the offending sugar(s) should result in clinical improvement.

Methods: A cohort of 239 patients defined as functional bowel complaints was divided into a group of 94 patients who met the Rome criteria for irritable bowel syndrome and a second group of 145 patients who did not fulfill these criteria and were defined as functional complaints.

Lactose (18 g), fructose (25 g) and a mixture of fructose (25 g) plus sorbitol (5 g) solutions were administered at weekly intervals. End-expiratory hydrogen and methane breath samples were collected at 30 minute intervals for 4 hours. Incomplete absorption was defined as an increment in breath hydrogen of at least 20 ppm, or its equivalent in methane of at least 5 ppm. All patients received a diet without the offending sugar(s) for one month.

Results: Only 7% of patients with IBS and 8% of patients with FC [functional bowel complaint] absorbed all three sugars normally.

The frequency of isolated lactose malabsorption was 16% and 12% respectively. The association of lactose and fructosesorbitol malabsorption occurred in 61% of both patient groups. The frequency of sugar malabsorption among patients in both groups was 78% for lactose malabsorption (IBS 82%, FC 75%), 44% for fructose malabsorption and 73% for fructose-sorbitol malabsorption (IBS 70%, FC 75%). A marked improvement occurred in 56% of IBS and 60% of FC patients following dietary restriction. The number of symptoms decreased significantly in both.

Conclusions: Combined sugar malabsorption patterns are common in functional bowel disorders and may contribute to symptomatology in most patients. Dietary restriction of the offending sugar(s) should be implemented before the institution of drug therapy.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10979349&dopt=Abstract