Effect of Fructose on Colonic Microflora (MEF)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00775567
Recruitment Status : Completed
First Posted : October 20, 2008
Last Update Posted : August 10, 2011
Information provided by:
Sir Mortimer B. Davis - Jewish General Hospital

Brief Summary:

Fructose is the principal carbohydrate in fruits and is added to many food products. This 6 carbon sugar is associated with a number of ill effects, like promotion of high triglycerides,precipitation of gout in men,possible depression in women and symptoms of intolerance in a non ethnic dose dependent fashion.However, high fruit and vegetable intake is associated with some epidemiologic evidence in prevention of some cancers like stomach and colorectum.The principal protectors in these products are thought to be antioxidants and other protective chemicals like polyphenols.In addition long chain polymers of fructose:inulin are thought to help protect against cancer through prebiotic effects. In fact poly-fructose molecules are used as prebiotic food supplements and are promoted as aids for a healthy intestine with "balanced microflora".

Polyfructose prebiotics induce some gastrointestinal symptoms of cramps gas bloating and sometimes diarrhea.To date repeated consumption of these polyfructose molecules have not been shown to induce colonic adaptation. Nor is there evidence that fructose intolerant people "adapt " to prolonged ingestion.

These findings are in contrast to findings with lactose intolerance where prolonged ingestion leads to both symptomatic and physiological adaptation.In this interventional study we evaluate whether fructose intolerant people can adapt to moderate dose daily fructose ingestion.The desired outcome is symptomatic, physiological and colonic microfloral adaptation. A failure to detect an increase in bifidobacteria on retesting may suggest that in humans like in some other mammals GLUT5 fructose transport could be induced.

Condition or disease Intervention/treatment
Healthy Dietary Supplement: Fructose powder

Detailed Description:

The concept of Colonic Adaptation(CA) to regular carbohydrates has been linked mainly to lactose disaccharide(galactose,glucose) and lactulose(galactose, fructose), a manufactured derivative of lactose. CA is achieved in both cases by short term regular consumption of the targeted sugar which is not digested by the host. The clinical definition of CA includes a measured change in breath hydrogen, reduction of clinical symptoms (Bloat, gas, cramps and at times diarrhea) and an associated increase of bacterial lactase(β-galactosidase. The putative mechanism is through bacterial action which results in enhanced metabolism or expanded bacterial population of specific genus and species of bacteria. The act of CA may incur health benefits through physicochemical changes and especially promotion of health promoting bacteria.

Maldigestion of fructose occurs in the population probably in a dose dependent fashion. The sugar content overwhelms the principal GLUT5 intestinal carrier. In the presence of glucose this non energy dependent system works better(11). In a previous publication we found that the pre test graded ingestion of fructose had no impact on test results. These results were dramatically different from that found for pretest lactose ingestion. The investigators interpreted the results from the fructose study as being consistent with a failure to show CA to regular fructose consumption.

More recently Rao et al however, showed that there may be a threshold level of intake beyond which fructose maldigestion may rapidly increase. This value was thought to be 15-20g. In the case of lactose this was 10g(15). Since in both our studies we used the same dose response analysis(<10,11-19, and >20g/d), it is possible that fructose consuming individuals might not have spilt adequate quantities of fructose into the colon to properly induce and maintain CA. Moreover, there is to our knowledge no information on a possible prebiotic effect of the monosaccharide fructose. Since polymers of fructose are very good prebiotics it may be of interest to determine whether this sugar is capable of prebiotic function in its own right.

The investigators propose to carry out a short term study on 20-30 healthy participants to determine whether a 2 week period of fructose consumption alters clinical CA and intestinal microflora.

Study Outline After an overnight fast, except for water(ad libitum), participants present themselves to the GI lab around 9 am. A 50 gm fructose solution (this dose is associated with a 65% chance of maldigestion(14))will be administered. Breath hydrogen and symptoms will be recorded for 4.5 Hrs at ½ hr intervals. Participants will be asked to fill out a short 3 day diet recall questionnaire targeting fructose ingestion.

Participants will be asked to consume 30g fructose in 150ml of water (lemon juice may be added) twice a day for 14 days.They will then return for a repeat50 g fructose challenge. A small stool sample will be asked from participants at each test period.Another similar group will undergo the same tests but without taking intervening fructose.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 45 participants
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Colonic Microbial and Clinical Adaptation to Large Doses of Fructose
Study Start Date : January 2008
Primary Completion Date : December 2008
Study Completion Date : December 2008

Resource links provided by the National Library of Medicine

Drug Information available for: Fructose
U.S. FDA Resources

Arm Intervention/treatment
Active Comparator: 1
30g fructose dissolved in water twice a day
Dietary Supplement: Fructose powder
30g in 250ml water twice a day
No Intervention: No Intervention

Primary Outcome Measures :
  1. Statistically significant reduction in total sum breath hydrogen upon a 50g fructose challenge test. [ Time Frame: intervention for 2 weeks per participant ]

Secondary Outcome Measures :
  1. A log 1 change in fecal bifidobacteria or lactobacilli species. [ Time Frame: stools retested 2 weeks apart ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy participants

Exclusion Criteria:

  • Antibiotics 90 days pre entry
  • Use of gastrointestinal motility drugs eg loperamide, metoclopramide significant fiber supplements
  • Pregnancy

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00775567

Canada, Quebec
SMBD Jewish General Hospital
Montreal, Quebec, Canada, H3T 1E2
Sponsors and Collaborators
Sir Mortimer B. Davis - Jewish General Hospital
Principal Investigator: Andrew Szilagyi, MD SMBD Jewish General Hospital, McGill university School of Medicine