# Hypothesis: fructose malabsorption causes SIBO



## Nanobug

As can be seen in this post, fructose malabsorption is associated with lower tryptophan levels. This leads me to hypothesize the following:1) Fructose malabsorption implies lower tryptophan levels (as per study)2) Lower tryptophan levels imply lower serotonin levels3) Lower serotonin levels eventually result in impaired gut motility4) Impaired gut motility eventually results in SIBOThis could also partly explain why SSRI's have such a good track record in helping people with IBS.The article Decreased Serum Zinc in Fructose Malabsorbers has a wealth of additional interesting information regarding this subject, including a notable sentence "We previously have shown that fructose malabsorption is a promoting factor for small intestinal bacterial overgrowth syndrome."


----------



## eric

Weight loss or malabsorbtion are "red flag" symptoms in IBS and require a organic workup to find the problem."Classic IBS" is a disorder of the large colon, and nutrients are already absorbed.People can have more then one condition.This is similar to the past when lactose intolerence was believed to be a cause of IBS. Fat, Fructose May Contribute to IBS Symptomshttp://www.medscape.com/viewarticle/462955Diet and Irritable Bowel Syndrome"Food IntoleranceFew randomized controlled trials of food intolerance have been reported.[10] Burden reviewed eight studies of food elimination; five demonstrated intolerance, but three did not. A major problem with these studies is that they included mostly patients who felt that food was a problem. Two studies of food withdrawal confirmed only 15% and 6% of patients with the suspected intolerance,[11,12] whereas one found that most patients had reported intolerance that responded to food withdrawal.[13] None of the patients in these studies, however, were rechallenged with the food of interest.Food components to which people are often intolerant include lactose, wheat products, monosaccharides (sorbitol, fructose, xylitol), and caffeine (in coffee, chocolate, cocoa, tea, cola, sodas).[10,14] The response to many foods is thought to be nonspecific by some experts, leading to the recommendation that diets be individualized in patients with IBS.[15*] The prevalence of food intolerance in the general population is about 15%,[16] but there is a discrepancy between reported intolerance and the result of controlled blinded trials of food withdrawal. About 45% of IBS patients appear to have lactose malabsorption, but only 30% have symptoms with milk products, and only 52% are improved with withdrawal of milk products. Lactose intolerance is difficult to evaluate because of the ability of bacterial metabolism in the colon to convert the malabsorbed sugar to metabolites that can be absorbed in the colon. Despite this difficulty in interpretation, such results have led to the suggestion that some of the symptoms attributed to food intolerance are in fact psychogenic in origin. This assessment is complicated by the observation that overeating leads to more gastrointestinal complaints.[16]Intestinal gas may be increased by certain foods, rising from around 15 ml/h in patients on a low-fiber diet to 170 ml/h when given a high-fiber (bean) diet.[17] The authors concluded that gas absorption may be impaired, but increased production could not be excluded.Food intolerance is commonly encountered in IBS patients as well as in the general population, but may be more noticeable in the IBS patient. Although discovery and treatment of intolerance(s) may improve symptoms, the patient is often left with significant residual symptoms that are due to the underlying IBS. Dietary management of food intolerances thus is an adjunct of IBS treatment.""Since I have suffered for thirty years of IBS I wonder what role foods play in IBS. So I asked Dr Douglas Drossman at the UNC Center for Functional GI and Motility disorders and here was his response. This is not a substitute for seeking medical advise from your doctor on any specific conditions you may have, but for educational purposes only. Dr. Drossman is a Co-director of the Center and Professor of Medicine and Psychiatry at UNC-CH. He established a program of research in functional gastrointestinal disorders at UNC more than 15 years ago and has published more than 250 books, articles, and abstracts relating to epidemiology, psychosocial and quality of life assessment, design of treatment trials, and outcomes research in gastrointestinal disorders. Dr Drossman's comments on foods for IBS Health.Shawn,To say that people with IBS may get symptoms from food intolerances is an acceptable possibility, since the gut will over react to stressors of all types including food (high fat or large volumes of food in particular). Futhermore, there can be specific intolerances. So if you have a lactose intolerance for example, it can exacerbate, or even mimic IBS. Other examples of food substances causing diarrhea would be high consumers of caffeine or alcohol which can stimulate intestinal secretion or with the latter, pull water into the bowel (osmotic diarrhea). The same would be true for overdoing certain poorly absorbed sugars that can cause an osmotic type of diarrhea Sorbitol, found in sugarless gum and sugar substituted foods can also produce such an osmotic diarrhea. Even more naturally, people who consume a large amount of fruits, juices or other processed foods enriched with fructose, can get diarrhea because it is not as easily absorbed by the bowel and goes to the colon where it pulls in water. So if you have IBS, all of these food items would make it worse. However, it is important to separate factors that worsen IBS (e.g., foods as above, stress, hormonal changes, etc.) from the cause or pathophysiology of IBS. Just like stress doesn't cause IBS, (though it can make it worse), foods must be understood as aggravating rather than etiological in nature. The cause of IBS is yet to be determined. However, modern research understands IBS as a disorder of increased reactivity of the bowel, visceral hypersensitivity and dysfunction of the brain-gut axis. There are subgroups being defined as well, including post-infectious IBS which can lead to IBS symptoms. Other work using brain imaging shows that the pain regulation center of the brain (cingulate cortex) can be impaired, as well as good evidence for there being abnormalities in motility which can at least in part explain the diarrhea and constipation. So finding a specific "cause" of IBS has grown out of general interest in place of understanding physiological subgroups that may become amenable to more specific treatments. Hope that helps.Doug "http://www.ibshealth.com/ibs_foods_2.htmChronic Diarrhea: Could It Have an Everyday Cause? "Fructose is a natural calorie-containing sugar found in fruit. It is one reason why large amounts of fruit can cause diarrhea. It may also be found in candies, soft drinks, honey, and preservatives and in sufficient amounts can cause diarrhea. Many people notice that their bowel movements are looser and more frequent in the summer when fresh fruits and vegetables are freely available. This is seldom a big problem, but moderating intake of these otherwise commendable foods should give comfort to some."http://www.aboutibs.org/Publications/chronicdiarrhea.htmlLI and SIBO Info"It is important to keep in mindthat *fructose is poorly absorbed by virtually everyone, which is the reason it is used* It is not possible to conclude whether IBS patients absorbfructose more poorly than healthy individuals, but it is clear that high levels ofconsumption of any poorly-absorbed sugar can cause symptoms similar to IBS andthat limiting consumption may result in symptom improvement."http://ibsgroup.org/groupee/forums?a=tpc&s...06862#412106862


----------



## eric

Onething to know about this is there is dietary fructose intolerence and Hereditary fructose intolerance.Dietary Fructose Intolerance http://www.uihealthcare.com/topics/medical.../dfi/index.htmlHereditary fructose intolerance http://www.healthatoz.com/healthatoz/Atoz/...intolerance.jsp


----------



## Nanobug

Eric, the hypothesis is that fructose malabsorption *causes* SIBO. I fail to see the relevance of your copy and paste in regards to this hypothesis.


----------



## eric

FYISmall Intestinal Bacterial Overgrowth(SIBO) Medical Author: Dennis Lee, MDMedical Editor: Jay W. Marks, MDWhat is small intestinal bacterial overgrowth (SIBO)? What causes small intestinal bacterial overgrowth? What are small intestinal bacterial overgrowth symptoms? What is the normal relationship between bacteria and the small intestine? What conditions cause increased production of gas? How does small intestinal bacterial overgrowth cause symptoms? How is small intestinal bacterial overgrowth diagnosed? Is there a relationship between small intestinal bacterial overgrowth and irritable bowel syndrome? How is small intestinal bacterial overgrowth treated? Whatâ€™s new in small intestinal bacterial overgrowth? Small Intestinal Bacterial Overgrowth (SIBO) At A Glance http://www.medicinenet.com/small_intestina...wth/article.htmThere are quite a few reasons for this that are known."This could also partly explain why SSRI's have such a good track record in helping people with IBS."Statistically they help 1 in three people.Your linking fructose malabsorption, tryptophan, serotonin IBS and sibo ect..In the case of IBS, altered motility alone doesn't fully explain pain in IBS.I could not find one abstract in pubmed on fructose malabsorbtion and sibo .It would be good to really understand what this means, because I am not toally sure about it."suggesting that sugar malabsorption findings may be falsely positive in patients with SIBO. Eradication of SIBO may normalize sugar breath levels. Therefore, tests for SIBO should be conducted before other sugar breath tests to avoid sugar malabsorption misdiagnosis."We should all know the lactulose breath testing is not the best method for testing for sibo.


----------

