Table of ContentsView AllTable of ContentsWhat Is Fructose?Types and CausesTests and DiagnosisSymptomsManagementFoods to AvoidWhen to Get HelpFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
What Is Fructose?
Types and Causes
Tests and Diagnosis
Symptoms
Management
Foods to Avoid
When to Get Help
Frequently Asked Questions
Fructoseis a sugar found in fruit, vegetables, and sweeteners. The amount of fructose people consume has increased over recent years, and it could be behind your stomach problems. While you may have heard of people needing to gogluten-freeor having alactose intolerance, some people have fructose intolerance.
This article will discuss the types of fructose intolerance, including causes and risk factors. Also learn symptoms, diagnosis, and how to manage this condition.
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Fructose is one of the naturally occurring sugars. It’s found in fruit, some vegetables, and honey.
Fructose is a simple sugar, like glucose. But unlike glucose, fructose isn’t directly used as energy. Instead, your small intestine and liver convert fructose into glucose so it can be stored and used for energy.
Most people can easily convert fructose to glucose without problems. However, some people can develop an intolerance to fructose, making it difficult for their bodies to metabolize (break down) fructose properly.
Types and Causes of Fructose Intolerance
Hereditary Fructose Intolerance
People with hereditary fructose intolerance are usually diagnosed once they are weaned from breastmilk or formula to fructose-containing solid foods, like fruit puree. However, because some infant formulas contain fructose, symptoms could develop earlier.
When someone with this condition eats fructose, the fructose builds up in the body and causes health problems, such as blood sugar crashes and liver damage.
Dietary Fructose Intolerance
Dietary fructose intolerance is more likely to develop when you’re an adult. The amount of fructose a person can tolerate will vary.
Diagnosing a fructose intolerance is challenging because it’s rare, and the symptoms are similar to other conditions. The types of tests used to diagnose a fructose intolerance depend on the type.
A hereditary intolerance can be slightly easier to diagnose, especially in infants, since foods are usually introduced slowly. If an infant frequently experiences symptoms and aversions to fructose-containing foods, it may indicate this intolerance.
Genetic testing for abnormalities in the aldolase B gene is the best test to confirm hereditary fructose intolerance. Other tests that may be used include:
When an adult is diagnosed with hereditary fructose intolerance, they typically have a history of avoiding sweets, fruits, and other fructose foods.
Diagnosing dietary fructose intolerance can be more challenging because the symptoms are similar to other conditions and food intolerances. Therefore, your healthcare provider may need to run several tests and rule out other conditions before you receive a diagnosis.
A food journal can help with the diagnosis because it helps you understand if there are any links between specific foods and when symptoms develop.
The best test for diagnosing fructose malabsorption is a breath test. During a breath test, the amount of methane and hydrogen in your breath is measured before and after drinking a fructose-containing beverage.The change in methane and hydrogen helps show how well your body is digesting fructose.
The symptoms and potential complications of hereditary fructose intolerance include:
The common symptoms of dietary fructose intolerance include:
It’s recommended for people with hereditary fructose intolerance to avoid consuming any fructose-containing foods. One case study reported a woman developed symptoms after consuming one sip of a sweetened beverage.
People with dietary fructose intolerance should follow a low-fructose diet. The exact amount of fructose they can consume without developing symptoms will vary. It’s best to try to avoid any high-fructose foods and add in foods low in fructose.
It’s recommended to avoid foods high in fructose. These include the following.
Fruits:
Vegetables:
Other foods:
Low-Fructose Fruits and Vegetables
When to See a Healthcare Provider
If you’re experiencing any of the symptoms of fructose intolerance, it’s best to contact your healthcare provider. The symptoms of fructose intolerance are similar to other health conditions, so it’s important to get a diagnosis to know the exact cause.
Your healthcare provider will also help you develop a treatment plan or refer you to a registered dietitian to help you follow a low-fructose diet.
Summary
Hereditary fructose intolerance is usually diagnosed with a genetic test to assess the aldolase B gene. Dietary fructose intolerance is generally diagnosed with a breath test after ingesting fructose.
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A Word From Verywell
It can feel daunting to be diagnosed with a condition like fructose intolerance because it eliminates many foods. Still, limiting your fructose can help ease your symptoms, and you’ll still be able to enjoy many delicious foods. Consider meeting with a dietitian to help you create a plan that works for you and still meets your nutrition needs.
Dietary fructose intolerance can develop as an adult, and symptoms could appear out of nowhere. However, if you have hereditary fructose intolerance, the symptoms will be present anytime you’re exposed to fructose and is usually diagnosed in infants.
A few low fructose fruits include cranberries, lime, kiwi, strawberries, bananas, and mandarin oranges.
Normally, fructose is metabolized within six hours after it’s consumed. However, it could stay in your system for a few days or weeks if you have fructose intolerance.
4 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Kim MS, Moon JS, Kim MJ, Seong MW, Park SS, Ko JS.Hereditary fructose intolerance diagnosed in adulthood.Gut Liver. 2021;15(1):142-145. doi:10.5009/gnl20189Montrose DC, Nishiguchi R, Basu S, et al.Dietary fructose alters the composition, localization, and metabolism of gut microbiota in association with worsening colitis.Cell Mol Gastroenterol Hepatol. 2021;11(2):525-550. doi:10.1016/j.jcmgh.2020.09.008Fedewa A, Rao SSC.Dietary fructose intolerance, fructan intolerance and FODMAPs.Curr Gastroenterol Rep. 2014;16(1):370. doi:10.1007/s11894-013-0370-0Schnedl WJ, Mangge H, Schenk M, Enko D.Non-responsive celiac disease may coincide with additional food intolerance/malabsorption, including histamine intolerance.Med Hypotheses. 2021;146:110404. doi:10.1016/j.mehy.2020.110404
4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Kim MS, Moon JS, Kim MJ, Seong MW, Park SS, Ko JS.Hereditary fructose intolerance diagnosed in adulthood.Gut Liver. 2021;15(1):142-145. doi:10.5009/gnl20189Montrose DC, Nishiguchi R, Basu S, et al.Dietary fructose alters the composition, localization, and metabolism of gut microbiota in association with worsening colitis.Cell Mol Gastroenterol Hepatol. 2021;11(2):525-550. doi:10.1016/j.jcmgh.2020.09.008Fedewa A, Rao SSC.Dietary fructose intolerance, fructan intolerance and FODMAPs.Curr Gastroenterol Rep. 2014;16(1):370. doi:10.1007/s11894-013-0370-0Schnedl WJ, Mangge H, Schenk M, Enko D.Non-responsive celiac disease may coincide with additional food intolerance/malabsorption, including histamine intolerance.Med Hypotheses. 2021;146:110404. doi:10.1016/j.mehy.2020.110404
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Kim MS, Moon JS, Kim MJ, Seong MW, Park SS, Ko JS.Hereditary fructose intolerance diagnosed in adulthood.Gut Liver. 2021;15(1):142-145. doi:10.5009/gnl20189Montrose DC, Nishiguchi R, Basu S, et al.Dietary fructose alters the composition, localization, and metabolism of gut microbiota in association with worsening colitis.Cell Mol Gastroenterol Hepatol. 2021;11(2):525-550. doi:10.1016/j.jcmgh.2020.09.008Fedewa A, Rao SSC.Dietary fructose intolerance, fructan intolerance and FODMAPs.Curr Gastroenterol Rep. 2014;16(1):370. doi:10.1007/s11894-013-0370-0Schnedl WJ, Mangge H, Schenk M, Enko D.Non-responsive celiac disease may coincide with additional food intolerance/malabsorption, including histamine intolerance.Med Hypotheses. 2021;146:110404. doi:10.1016/j.mehy.2020.110404
Kim MS, Moon JS, Kim MJ, Seong MW, Park SS, Ko JS.Hereditary fructose intolerance diagnosed in adulthood.Gut Liver. 2021;15(1):142-145. doi:10.5009/gnl20189
Montrose DC, Nishiguchi R, Basu S, et al.Dietary fructose alters the composition, localization, and metabolism of gut microbiota in association with worsening colitis.Cell Mol Gastroenterol Hepatol. 2021;11(2):525-550. doi:10.1016/j.jcmgh.2020.09.008
Fedewa A, Rao SSC.Dietary fructose intolerance, fructan intolerance and FODMAPs.Curr Gastroenterol Rep. 2014;16(1):370. doi:10.1007/s11894-013-0370-0
Schnedl WJ, Mangge H, Schenk M, Enko D.Non-responsive celiac disease may coincide with additional food intolerance/malabsorption, including histamine intolerance.Med Hypotheses. 2021;146:110404. doi:10.1016/j.mehy.2020.110404
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