Irritable Bowel Syndrome Message Boards

Let me answer you question in two parts.

The first part addresses the questions you asked about the research that I pointed out to you.

The second part which I will post later will explain what is meant by fructose malabsorption, how it differs from hereditary fructose intolerance and how management of dietary fructose and fructans (molecules made up of chains of fructose molecules) is beneficial for the management of IBS-D and IBS-C.

The researchers in the study used the lactulose test and checked for early rise breath hydrogen. They were trying to show early rise hydrogen in the breath test after ingesting lactulose is a common physiological response and not a valid test for SIBO. Like Drossman and others they found this to be the case and concluded it is an inaccurate test for SIBO.

In addition they showed that fructose malabsorption and lactose malabsorption, which are also diagnosed with a breath test, are common physiological responses. About 35% of health individuals and 45% of the FGID population have fructose malabsorption. And a significant percentage of IBS-D and IBS-C (48-55%) population suffers from fructose malabsorption. It isn't strictly associated with IBS-D.

In summary this research shows that lactose and fructose malabsorption are not causes of FGIDs perhaps with the exception of Crohn's disease where the high occurrence (61%) of fructose malabsorption is currently unexplainable. The lactulose breath test is not reliable for diagnosing SIBO. And fructose malabsorption affects a significant percentage of FGID population and occurs equally as frequently in the IBS-D and IBS-C population.

Now turn let us ask another question. Can dietary fructose be an IBS trigger?

Note the last sentence in the quote you posted from Sue Shepherd's article. It says "As outlined earlier, the response to fructose is exaggerated in patients with IBS compared with those without IBS." She and others in the Australian research team have gone further. The published a study reference below with a link to the abstract in the research library reporting the results of a small clinical trial. They wanted to see whether dietary fructose restriction or more generally speaking whether poorly absorbed short-chain carbohydrates (sometimes called FODMAPs) such as fructose and fructans improved IBS symptoms. They found in IBS patients with fructose malabsorption, which is about 50% of the total IBS population, that dietary restriction of fructose and/or fructans improved IBS symptoms.

Generally speaking it seems that dietary fructose and fructans can be IBS triggers for approximately 50% of the IBS populations. It is worth while considering restricting certain foods when designing a personal IBS management plan.

In the next posting I will explain the difference between fructose malabsorption and hereditary fructose intolerance and what is meant by restricted dietary fructose and/or fructan consumption in the pratical design of a personal IBS management plan.

Reference
Shepherd, S. J., Parker, F. C., Muir, J. G., & Gibson, P. R. (2008). Dietary Triggers of Abdominal Symptoms in Patients With Irritable Bowel Syndrome: Randomized Placebo-Controlled Evidence . Clinical Gastroenterology and Hepatology, 6, 765-771

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STABLE: ♂, IBS-D 50+ years - Science of IBS

The FODMAP Approach to Managing IBS Symptoms
Evidence-based Dietary Management of Functional GI Symptoms: The FODMAP Approach
FODMAP Chart & Cheatsheet
The Role of Food & Dietary Intervention in IBS

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