View source for Fructose malabsorption

{{Use dmy dates|date=February 2021}}
{{Infobox medical condition (new)
| name            = Fructose malabsorption
| synonyms        = Dietary fructose intolerance
| image           = Beta-D-Fructofuranose.svg
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| caption         = Chemical structure of [[fructose]]
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'''Fructose malabsorption''', formerly named '''dietary fructose intolerance''' ('''DFI'''), is a digestive disorder<ref>[http://www.mayoclinic.com/health/fructose-intolerance/AN01574 MayoClinic.com]</ref> in which absorption of [[fructose]] is impaired by deficient [[fructose carrier]]s in the small intestine's [[enterocyte]]s. This results in an increased concentration of [[fructose]]. Intolerance to fructose was first identified and reported in 1956.<ref>{{cite journal |doi=10.1016/S0140-6736(56)92196-1 |pmid=13358219 |title=Idiosyncrasy to Fructose |journal=The Lancet |volume=268 |issue=6938 |pages=340 |year=1956 |last1=Chambers |first1=R.A |last2=Pratt |first2=R.T.C }}</ref>

Similarity in symptoms means that patients with fructose malabsorption often fit the profile of those with irritable bowel syndrome.<ref>{{cite journal  |vauthors=Ledochowski M, etal |title=Fruktosemalabsorption |journal=Journal für Ernährungsmedizin |volume=3 |issue=1 |pages=15–19 |year=2001 |url=http://www.kup.at/kup/pdf/305.pdf |language=de}}</ref>

Fructose malabsorption is not to be confused with [[hereditary fructose intolerance]], a potentially fatal condition in which the liver [[enzymes]] that break up fructose are deficient. Hereditary fructose intolerance is quite rare, affecting up to 1 in 20,000 to 30,000 people.{{citation needed|date=July 2023}}

==Symptoms and signs==
Fructose malabsorption may cause gastrointestinal symptoms such as abdominal pain, [[bloating]], [[flatulence]] or [[diarrhea]].<ref name=EbertWitt2016 /><ref name=PutkonenYao2013>{{cite journal|vauthors=Putkonen L, Yao CK, Gibson PR|title=Fructose malabsorption syndrome|journal=Curr Opin Clin Nutr Metab Care|volume=16|issue=4|pages=473–7|date=Jul 2013|pmid=23739630|doi=10.1097/MCO.0b013e328361c556|s2cid=3124240|type=Review|doi-access=free}}</ref>

== Pathophysiology ==
Fructose is absorbed in the small intestine without help of digestive enzymes. Even in healthy persons, however, only about 25–50&nbsp;g of fructose per sitting can be properly absorbed. People with fructose malabsorption absorb less than 25&nbsp;g per sitting.<ref>{{Cite web | url=http://www.uihealthcare.com/kxic/2008/06/fructose.html | title=University of Iowa Hospitals & Clinics}}</ref> Simultaneous ingestion of fructose and [[sorbitol]] seems to increase [[malabsorption]] of fructose.<ref name=BerniCananiPezzella2016>{{cite journal |doi=10.3390/nu8030157 |pmid=26978392 |pmc=4808885 |title=Diagnosing and Treating Intolerance to Carbohydrates in Children |journal=Nutrients |volume=8 |issue=3 |pages=157 |year=2016 |last1=Berni Canani |first1=Roberto |last2=Pezzella |first2=Vincenza |last3=Amoroso |first3=Antonio |last4=Cozzolino |first4=Tommaso |last5=Di Scala |first5=Carmen |last6=Passariello |first6=Annalisa |doi-access=free }}</ref> Fructose that has not been adequately absorbed is fermented by intestinal bacteria producing [[hydrogen]], [[carbon dioxide]], [[methane]] and [[short-chain fatty acid]]s.<ref name=EbertWitt2016>{{cite journal |doi=10.1186/s40348-016-0035-9 |pmid=26883354 |pmc=4755956 |title=Fructose malabsorption |journal=Molecular and Cellular Pediatrics |volume=3 |issue=1 |pages=10 |year=2016 |last1=Ebert |first1=Karolin |last2=Witt |first2=Heiko |doi-access=free }}</ref><ref name=MontaltoGallo2013>{{cite journal|vauthors=Montalto M, Gallo A, Ojetti V, Gasbarrini A|title=Fructose, trehalose and sorbitol malabsorption|journal=Eur Rev Med Pharmacol Sci|volume=17|issue=Suppl 2|pages=26–9|year=2013|pmid=24443064|url=http://www.europeanreview.org/wp/wp-content/uploads/026-0291.pdf|type=Review}}</ref> This abnormal increase in hydrogen may be detectable with the [[hydrogen breath test]].<ref name=BerniCananiPezzella2016 />

The physiological consequences of fructose malabsorption include increased osmotic load, rapid bacterial fermentation, altered [[gastrointestinal motility]], the formation of mucosal [[biofilm]] and altered [[Gut flora|profile of bacteria]]. These effects are additive with other short-chain poorly absorbed carbohydrates such as [[sorbitol]]. The clinical significance of these events depends upon the response of the bowel to such changes. Some effects of fructose malabsorption are decreased [[tryptophan]],<ref>{{cite journal |vauthors=Ledochowski M, Widner B, Murr C, Sperner-Unterweger B, Fuchs D |title=Fructose malabsorption is associated with decreased plasma tryptophan |journal=Scand. J. Gastroenterol. |volume=36 |issue=4 |pages=367–71 |year=2001 |pmid=11336160 |doi=10.1080/003655201300051135|citeseerx=10.1.1.627.6642 }}</ref> [[folic acid]]<ref name=Ledochowski99 /> and [[zinc]] in the blood.<ref name=Ledochowski99>{{cite journal |vauthors=Ledochowski M, Uberall F, Propst T, Fuchs D |title=Fructose malabsorption is associated with lower plasma folic acid concentrations in middle-aged subjects |journal=Clin. Chem. |volume=45 |issue=11 |pages=2013–4 |year=1999 |doi=10.1093/clinchem/45.11.2013 |pmid=10545075 |url=http://www.clinchem.org/cgi/content/full/45/11/2013|doi-access=free }}</ref>

Restricting dietary intake of free fructose and/or [[fructan]]s may provide symptom relief in a high proportion of patients with functional gut disorders.<ref name="pmid17217453">{{cite journal |doi=10.1111/j.1365-2036.2006.03186.x |pmid=17217453 |title=Review article: Fructose malabsorption and the bigger picture |journal=Alimentary Pharmacology & Therapeutics |volume=25 |issue=4 |pages=349–63 |year=2006 |last1=Gibson |first1=P. R |last2=Newnham |first2=E |last3=Barrett |first3=J. S |last4=Shepherd |first4=S. J |last5=Muir |first5=J. G |doi-access= }}</ref>

== Diagnosis ==
The diagnostic test, when used, is similar to that used to diagnose [[lactose intolerance]]. It is called a [[Hydrogen Breath Test|hydrogen breath test]] and is the method currently used for a clinical [[medical diagnosis|diagnosis]]. Nevertheless, some authors argue this test is not an appropriate diagnostic tool, because a negative result does not exclude a positive response to fructose restriction, implying a lack of sensitivity.<ref name=BerniCananiPezzella2016 />

== Treatment ==

=== Physical activity (avoiding sitting down for long periods) ===
Sitting down can cause your abdomen to compress, which slows down digestion. This can lead to issues such as bloating, heartburn and constipation.<ref>{{Cite web|date=2019-03-26|title=What Sitting All Day Does To Your Body (Spoiler Alert: It's Not Great)|url=https://www.huffingtonpost.co.uk/entry/how-sitting-all-day-affects-the-body_uk_5930184de4b0540ffc84d81c|access-date=2021-09-03|website=HuffPost UK|language=en}}</ref> It could thus increase or cause fructose malabsorption. A study shows that physical activity between long periods of sitting is not enough: "focusing on acquiring the recommended dose of exercise is not strong enough of a stimulant to completely protect the body from physical inactivity the other 23+ h/day".<ref>{{Cite journal|last1=Gardiner|first1=Paul A.|last2=Healy|first2=Genevieve N.|last3=Eakin|first3=Elizabeth G.|last4=Clark|first4=Bronwyn K.|last5=Dunstan|first5=David W.|last6=Shaw|first6=Jonathan E.|last7=Zimmet|first7=Paul Z.|last8=Owen|first8=Neville|date=May 2011|title=Associations Between Television Viewing Time and Overall Sitting Time with the Metabolic Syndrome in Older Men and Women: The Australian Diabetes Obesity and Lifestyle Study|url=http://dx.doi.org/10.1111/j.1532-5415.2011.03390.x|journal=Journal of the American Geriatrics Society|volume=59|issue=5|pages=788–796|doi=10.1111/j.1532-5415.2011.03390.x|pmid=21568949|s2cid=19714433|issn=0002-8614|url-access=subscription}}</ref> "Reducing prolonged overall sitting time may reduce metabolic disturbances"<ref>{{Cite journal|last=Bidwell|first=Amy J.|date=2017-05-28|title=Chronic Fructose Ingestion as a Major Health Concern: Is a Sedentary Lifestyle Making It Worse? A Review|journal=Nutrients|volume=9|issue=6|page=549|doi=10.3390/nu9060549|issn=2072-6643|pmc=5490528|pmid=28555043|doi-access=free}}</ref>

=== Dietary supplements ===
[[Xylose isomerase]] acts to convert fructose sugars into glucose. [[Dietary supplements]] of xylose isomerase may improve some symptoms of fructose malabsorption, although there is currently only a single scientific study available.<ref name="Komericki2012">{{cite journal|last1=Komericki|first1=P.|last2=Akkilic-Materna|first2=M.|last3=Strimitzer|first3=T.|last4=Weyermair|first4=K.|last5=Hammer|first5=H.F.|last6=Aberer|first6=W.|year=2012|title=Oral xylose isomerase decreases breath hydrogen excretion and improves gastrointestinal symptoms in fructose malabsorption – a double-blind, placebo-controlled study|journal=Alimentary Pharmacology & Therapeutics|volume=36|issue=10|pages=980–987|doi=10.1111/apt.12057|pmid=23002720|doi-access=free}}</ref>

=== Diet ===
There is no known cure, but an appropriate [[diet (nutrition)|diet]] and the enzyme [[xylose isomerase]] can help.<ref name="BerniCananiPezzella2016" /> The ingestion of glucose simultaneously with fructose improves fructose absorption and may prevent the development of symptoms. For example, people may tolerate fruits such as grapefruits or bananas, which contain similar amounts of fructose and glucose, but apples are not tolerated because they contain high levels of fructose and lower levels of glucose.<ref name="EbertWitt2016" /> But a randomised controlled trials in patients with fructose malabsorption (made by the Cochrane institute) found that "Adding glucose to food and solutions to enhance fructose absorption is not effective in preventing fructose-induced functional gastrointestinal symptoms".<ref>{{Cite journal|last1=Tuck|first1=C. J.|last2=Ross|first2=L. A.|last3=Gibson|first3=P. R.|last4=Barrett|first4=J. S.|last5=Muir|first5=J. G.|date=2017|title=Adding glucose to food and solutions to enhance fructose absorption is not effective in preventing fructose-induced functional gastrointestinal symptoms: randomised controlled trials in patients with fructose malabsorption|url=https://onlinelibrary.wiley.com/doi/abs/10.1111/jhn.12409|journal=Journal of Human Nutrition and Dietetics|language=en|volume=30|issue=1|pages=73–82|doi=10.1111/jhn.12409|pmid=27600184|s2cid=3722940|issn=1365-277X|url-access=subscription}}</ref>

Foods that should be avoided by people with fructose malabsorption include:
* Foods and beverages containing '''greater than 0.5 g fructose''' in excess of glucose per 100&nbsp;g and greater than 0.2 g of fructans per serving should be avoided. Foods with >3 g of fructose per serving are termed a 'high fructose load' and possibly present a risk of inducing symptoms. However, the concept of a 'high fructose load' has not been evaluated in terms of its importance in the success of the diet.<ref name=Gibson10>{{cite journal |doi=10.1111/j.1440-1746.2009.06149.x |pmid=20136989 |title=Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach |journal=Journal of Gastroenterology and Hepatology |volume=25 |issue=2 |pages=252–8 |year=2010 |last1=Gibson |first1=Peter R |last2=Shepherd |first2=Susan J |doi-access=free }}</ref>
* Foods with high '''fructose-to-glucose ratio'''. Glucose enhances absorption of fructose, so fructose from foods with fructose-to-glucose ratio <1, like white potatoes, are readily absorbed, whereas foods with fructose-to-glucose ratio >1, like apples and pears, are often problematic regardless of the total amount of fructose in the food.<ref>{{Cite web |url=http://www.healthsystem.virginia.edu/internet/digestive-health/nutrition/BarrettArticle.pdf |title=Division of Gastroenterology & Hepatology — School of Medicine at the University of Virginia |access-date=2 December 2007 |archive-date=18 May 2012 |archive-url=https://web.archive.org/web/20120518025101/http://www.medicine.virginia.edu/clinical/departments/medicine/divisions/digestive-health |url-status=dead }}</ref>
* Foods rich in [[fructans]] and other fermentable oligo-, di- and mono-saccharides and polyols ('''[[FODMAP]]s'''), including [[artichoke]]s, [[asparagus]], [[Leek (vegetable)|leeks]], [[onion]]s, and [[wheat]]-containing products, including [[bread]]s, [[cake]]s, [[biscuit]]s, [[breakfast cereal]]s, [[pie]]s, [[pasta]]s, [[pizza]]s, and wheat [[noodle]]s.
:The role that fructans play in fructose malabsorption is still under investigation. However, it is recommended that fructan intake for fructose malabsorbers should be kept to less than 0.5&nbsp;grams/serving,<ref name=Shepherd06>{{cite journal |vauthors=Shepherd SJ, Gibson PR |title=Fructose malabsorption and symptoms of irritable bowel syndrome: guidelines for effective dietary management |journal=Journal of the American Dietetic Association |volume=106 |issue=10 |pages=1631–9 |year=2006 |pmid=17000196 |doi=10.1016/j.jada.2006.07.010 |url=http://sacfs.asn.au/download/SueShepherd_sarticle.pdf |access-date=14 October 2007 |archive-date=14 March 2011 |archive-url=https://web.archive.org/web/20110314222733/http://sacfs.asn.au/download/SueShepherd_sarticle.pdf |url-status=dead }}</ref> and supplements with ''[[inulin]]'' and ''[[fructooligosaccharide]]'' (FOS), both fructans, should be avoided.<ref name=Shepherd06 />
* Foods containing '''artificial sweeteners''' like [[sorbitol]] (present in some [[diet food|diet drinks and foods]] and occurring naturally in some [[stone fruit]]s), [[xylitol]] (present in some berries) and other '''[[polyols]]''' (sugar alcohols, such as [[erythritol]], [[mannitol]] and other ingredients that end with -tol, commonly added as  in commercial foods).
* Foods containing '''[[high fructose corn syrup]]'''.

Foods with a high glucose content ingested with foods containing excess fructose may help patients absorb the excess fructose.<ref>{{cite journal |vauthors=Skoog SM, Bharucha AE |title=Dietary fructose and gastrointestinal symptoms: a review |journal=Am. J. Gastroenterol. |volume=99 |issue=10 |pages=2046–50 |year=2004 |doi=10.1111/j.1572-0241.2004.40266.x |pmid=15447771 |s2cid=12084142 |url=http://www.bashaar.org.il/files/101022005111814.pdf |access-date=23 July 2006 |archive-date=1 April 2017 |archive-url=https://web.archive.org/web/20170401082345/http://www.bashaar.org.il/files/101022005111814.pdf |url-status=dead }}</ref>

==== Foods with high fructose content ====
According to the USDA database,<ref>[https://www.nal.usda.gov/human-nutrition-and-food-safety/dri-calculator USDA National Nutrient Database]  Release 20, September 2007</ref> foods with more fructose than glucose include:

{| class="wikitable sortable"
! Food
! data-sort-type="number" | Fructose (grams / 100&nbsp;grams)
! data-sort-type="number" | Glucose (grams / 100&nbsp;grams)
!Fructose/Glucose Ratio
|- align="center"
| [[Sucrose]]<br />(for reference)
| 50
| 50
| align="right" |1
|- align="center"
| Apples
| 5.9
| 2.4
| align="right" |2.46
|- align="center"
| Pears
| 6.2
| 2.8
| align="right" |2.21
|- align="center"
| [[Fruit juice]] <br />e.g. Apples, <br />Pears
| 5–7
| 2–3
| align="right" |~2.4
|- align="center"
| [[Watermelon]]
| 3.4
| 1.6
| align="right" |2.13
|- align="center"
| [[Raisin]]s
| 29.8
| 27.8
| align="right" |1.07
|- align="center"
| [[Honey]]
| 40.9
| 35.7
| align="right" |1.15
|- align="center"
| [[High fructose corn syrup|High fructose <br />corn syrup]] (dry mass)
| 42–55
| 45–58
| align="right" |.72-1.22
|- align="center"
| [[Mango]]
| 4.68
| 2.01
| align="right" |2.33
|- align="center"
| [[Agave nectar]]
| 55.6
| 12.43
| align="right" |4.47
|- align="center"
| [[Ginger]]
| 1.78
| 1.22
| align="right" |1.46
|}

The USDA food database reveals that many common fruits contain nearly equal amounts of the fructose and glucose, and they do not present problems for those individuals with fructose malabsorption.<ref>[http://www.nal.usda.gov/fnic/foodcomp/Data/Other/herr48.pdf Sugar Content of Selected Foods:  Individual and Total Sugars] {{webarchive|url=https://web.archive.org/web/20060907155335/http://www.nal.usda.gov/fnic/foodcomp/Data/Other/herr48.pdf |date=7 September 2006 }} Ruth H. Matthews, Pamela R. Pehrsson, and Mojgan Farhat-Sabet, (1987) [[U.S.D.A.]]</ref> Some fruits with a greater ratio of fructose than glucose are apples, pears and watermelon, which contain more than twice as much fructose as glucose. Fructose levels in grapes varies depending on ripeness and variety, where unripe grapes contain more glucose.

=== Dietary guidelines for management ===
Researchers at [[Monash University]] in Australia developed dietary guidelines<ref name=Shepherd06 /> for managing fructose malabsorption, particularly for individuals with IBS.

==== Unfavorable foods (i.e. more fructose than glucose) ====
* Fruit&nbsp;– [[apple]], [[pear]], [[honeydew melon]], [[nashi pear]], [[Asimina triloba|pawpaw]], [[papaya]], [[quince]], [[star fruit]], [[watermelon]];
* Dried fruit – apple, currant, [[Phoenix dactylifera|date]], [[Common fig|fig]], pear, [[raisin]], [[sultana (grape)|sultana]];
* [[Fortified wines]]
* Foods containing added sugars, such as [[agave nectar]], some [[corn syrup]]s, and fruit juice concentrates.

==== Favorable foods (i.e. fructose equal to or less than glucose) ====
The following list of favorable foods was cited in the paper: "Fructose malabsorption and symptoms of Irritable Bowel Syndrome Guidelines for effective dietary management".<ref name=Shepherd06 /> The fructose and glucose contents of foods listed on the Australian food standards<ref>{{cite web|url=http://www.foodstandards.gov.au/consumerinformation/nuttab2010/nuttab2010onlinesearchabledatabase/onlineversion.cfm?action=nutrientFoods&category=Proximates&nutrientID=FRU|title=NUTTAB 2010 Online Searchable Database|publisher=[[Food Standards Australia New Zealand]]|access-date=7 July 2013|archive-url=https://web.archive.org/web/20120324031237/http://www.foodstandards.gov.au/consumerinformation/nuttab2010/nuttab2010onlinesearchabledatabase/onlineversion.cfm?&action=nutrientFoods&category=Proximates&nutrientID=FRU|archive-date=2012-03-24}}</ref> would appear to indicate that most of the listed foods have higher fructose levels.
* [[Stone fruit]]: [[apricot]], [[nectarine]], [[peach]], [[plum]] (caution – these fruits contain [[sorbitol]]);
* [[Berry fruit]]: [[blackberry]], [[boysenberry]], [[cranberry]], [[raspberry]], [[strawberry]], [[loganberry]];
* [[Citrus fruit]]: [[kumquat]], [[grapefruit]], [[lemon]], [[lime (fruit)|lime]], [[mandarin orange|mandarin]], [[orange (fruit)|orange]], [[tangelo]];
* Other fruits: ripe [[banana]], [[jackfruit]], [[passion fruit]], [[pineapple]], [[rhubarb]], [[tamarillo]].

== Food-labeling ==
Producers of processed food in most or all countries, including the US, are not currently required by law to mark foods containing "fructose in excess of glucose". This can cause some surprises and pitfalls for fructose malabsorbers.{{citation needed|date=September 2021}}

Foods (such as bread) marked "gluten-free" are usually suitable for fructose malabsorbers, though they need to be careful of gluten-free foods that contain [[dried fruit]] or high fructose corn syrup or [[fructose]] itself in sugar form. However, fructose malabsorbers do ''not'' need to avoid [[gluten]], as those with [[Coeliac disease|celiac disease]] must.{{citation needed|date=September 2021}}

Many fructose malabsorbers can eat breads made from [[rye]] and [[maize|corn]] flour. However, these may contain wheat unless marked "wheat-free" (or "gluten-free") (Note: Rye bread is ''not'' gluten-free.) Although often assumed to be an acceptable alternative to wheat, [[spelt]] flour is not suitable for people with fructose malabsorption{{Citation needed|date=October 2010}}, just as it is not appropriate for those with [[wheat allergy|wheat allergies]] or celiac disease. However, some fructose malabsorbers do not have difficulty with fructans from wheat products while they may have problems with foods that contain excess free fructose.{{Citation needed|date=January 2012}}

There are many breads on the market that boast having no [[high fructose corn syrup]].  In lieu of high fructose corn syrup, however, one may find the production of special breads with a high inulin content, where [[inulin]] is a replacement in the [[baking]] process for the following: high fructose corn syrup, flour and fat.  Because of the caloric reduction, lower fat content, dramatic fiber increase and [[Prebiotic (nutrition)|prebiotic]] tendencies of the replacement inulin, these breads are considered a healthier alternative to traditionally prepared [[leavening]] breads.  Though the touted health benefits may exist, people with  fructose malabsorption will likely find no difference between these new breads and traditionally prepared breads in alleviating their symptoms because inulin is a [[fructan]], and, again, consumption of fructans should be reduced dramatically in those with fructose malabsorption in an effort to appease symptoms.{{citation needed|date=September 2021}}

== Research ==
Fructose and [[fructan]]s are [[FODMAP]]s (fermentable oligo-, di- and mono-saccharides and polyols) known to cause gastrointestinal discomfort in susceptible individuals. FODMAPs are not the cause of these disorders,<ref name="GibsonShepherd2010" /> but FODMAPs restriction (a [[low-FODMAP diet]]) might help to improve short-term digestive symptoms in adults with [[irritable bowel syndrome]] (IBS) and other [[functional gastrointestinal disorder]]s (FGID).<ref name="GibsonShepherd2010">{{cite journal|author=Peter R Gibson|author2=Susan J Shepherd|name-list-style=amp|title=Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach|journal=Journal of Gastroenterology and Hepatology|year=2010|volume=25|pages=252–258|doi=10.1111/j.1440-1746.2009.06149.x|pmid=20136989|issue=2|doi-access=free}}</ref><ref name="TurcoSalvatore2018">{{cite journal| vauthors=Turco R, Salvatore S, Miele E, Romano C, Marseglia GL, Staiano A| title=Does a low FODMAPs diet reduce symptoms of functional abdominal pain disorders? A systematic review in adult and paediatric population, on behalf of Italian Society of Pediatrics. | journal=Ital J Pediatr | year= 2018 | volume= 44 | issue= 1 | article-number= 53 | pmid=29764491 | doi=10.1186/s13052-018-0495-8 | pmc=5952847 | type=Systematic Review | doi-access=free }}</ref><ref name=Staudacher>{{cite journal |vauthors=Staudacher HM, Irving PM, Lomer MC, Whelan K |title=Mechanisms and efficacy of dietary FODMAP restriction in IBS |journal=Nat Rev Gastroenterol Hepatol |volume=11 |issue=4 |pages=256–66 | date=April 2014 |pmid=24445613 |doi=10.1038/nrgastro.2013.259 |s2cid=23001679 |type=Review |quote=An emerging body of research now demonstrates the efficacy of fermentable carbohydrate restriction in IBS.&nbsp;[...]&nbsp;However, further work is urgently needed both to confirm clinical efficacy of fermentable carbohydrate restriction in a variety of clinical subgroups and to fully characterize the effect on the gut microbiota and the colonic environ¬ment. Whether the effect on luminal bifidobacteria is clinically relevant, preventable, or long lasting, needs to be investigated. The influence on nutrient intake, dietary diversity, which might also affect the gut microbiota,137 and quality of life also requires further exploration as does the possible economic effects due to reduced physician contact and need for medication. Although further work is required to confirm its place in IBS and functional bowel disorder clinical pathways, fermentable carbohydrate restriction is an important consideration for future national and international IBS guidelines. }}</ref><ref name="RaoYu2015">{{cite journal |vauthors=Rao SS, Yu S, Fedewa A |title=Systematic review: dietary fibre and FODMAP-restricted diet in the management of constipation and irritable bowel syndrome |journal=Aliment. Pharmacol. Ther. |volume=41 |issue=12 |pages=1256–70 |year=2015 |pmid=25903636 |doi=10.1111/apt.13167|s2cid=27558785 |doi-access=free }}</ref> Nevertheless, its long-term follow-up can have negative effects because it causes a detrimental impact on the [[gut microbiota]] and [[metabolome]].<ref name=Staudacher /><ref name="RaoYu2015" /><ref name="GibsonTuck2014">{{cite journal|last1=Tuck|first1=CJ|last2=Muir|first2=JG|last3=Barrett|first3=JS|last4=Gibson|first4=PR|title=Fermentable oligosaccharides, disaccharides, monosaccharides and polyols: role in irritable bowel syndrome|journal=Expert Rev Gastroenterol Hepatol|year=2014|volume=8|issue=7|pages=819–834|doi=10.1586/17474124.2014.917956|pmid=24830318|s2cid=28811344}}</ref><ref name="HeimanGreenway2016">{{cite journal| vauthors=Heiman ML, Greenway FL| title=A healthy gastrointestinal microbiome is dependent on dietary diversity. | journal=Mol Metab | year= 2016 | volume= 5 | issue= 5 | pages= 317–320 | pmid=27110483 | doi=10.1016/j.molmet.2016.02.005 | pmc=4837298 | type=Review }}</ref>

== See also ==
* [[Hereditary fructose intolerance]]
* [[Food intolerance]]
* [[Gastroenterology]]
* [[Invisible disability]]

== References ==
{{Reflist}}

== External links ==
{{Medical resources
|   DiseasesDB     =
|   ICD10          = {{ICD10|E|74|3|e|70}}
|   ICD9           = {{ICD9|271}}
|   ICDO           =
|   OMIM           = 138230
|   MedlinePlus    =
|   eMedicineSubj  =
|   eMedicineTopic =
|   MeshID         =
}}

{{Gastroenterology}}
{{Solute carrier disorders}}
{{Inborn errors of carbohydrate metabolism}}

[[Category:Membrane transport protein disorders]]
[[Category:Inborn errors of carbohydrate metabolism]]