Taking people in United StatesNo phase

Tests how a high fructose diet affects gut bacteria and metabolic health

Compares fructose and glucose diets in adults with liver fat, obesity, or diabetes.

Key facts

Who runs it: Icahn School of Medicine at Mount Sinai
Where: New York, United StatesSee the site
Trial code: NCT06329544
Registry title: High Fructose Diet, the Gut Microbiome, and Metabolic Health
Status: Recruiting
People taking part: 30 people, planned
Started: 8 Oct 2024
Expected to end: 31 Aug 2028
Type of study: Interventional, 2 groups
Treatments tested: Fructose
glucose
Record updated: 17 December 2025

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for adults aged 25 to 45 who do not absorb fructose well, shown by a hydrogen breath test. They eat controlled fructose and glucose diets.

Age: 25 to 45 years
Sex: All sexes can join
Earlier treatment: No antibiotics in the 3 months before joining or during the trial. No probiotic, prebiotic or synbiotic supplements.
Biomarker or test result: Fructose malabsorption shown by a hydrogen breath test at the screening visit.

Main reasons for not taking part

A major medical illness, including type 1 or type 2 diabetes, or an eating disorder
Daily medicine that may affect body weight, insulin resistance or blood fats
Smoking or recreational drug use
More than 1 sugar sweetened drink per day, or more than 2 alcoholic drinks per day
Vegetarian, vegan or other restrictive diet, or a food allergy

The registry criteria, word for word

Show all 15 criteriaShow less

Who can take part

Participants must be determined to be a fructose malabsorber (screening visit) via hydrogen breath test

Who cannot take part

Antibiotics within 3 months prior to enrollment or during intervention
Chronic use of any medication that may affect body weight or composition, insulin resistance, or lipid profiles
Current smoking (more than 1 cigarette in the past week) or use of other recreational drugs; e) restrictive dietary habits
recent use of pro-, pre- or Synbiotics of receipt of antibiotics within 3 months prior to enrollment or during the intervention
consumption of greater than 1 sugar sweetened beverage per day prior to enrollment
Food allergy
Physician diagnosis of a major medical illness (including type 1 or type 2 diabetes) or eating disorder
food allergy
Use of probiotic/prebiotic/synbiotic supplements
Consumption of > 1 sugar sweetened beverage per day
Vegetarian, vegan or other restrictive dietary habits
Alcohol consumption in excess of 2 drink per day; The following additional factors will be exclusion criteria:
Physical, mental, or cognitive handicaps that prevent participation
excess alcohol consumption

Check if you might fit

Answer for yourself. This is not a decision: only the study team can say whether you can take part.

Are you between 25 and 45 years old?

Where in United States

Mount Sinai MorningsideNew York, United StatesContact: Ryan Walker (principal investigator)Taking people

About the trial

What the trial wants to find out

Americans commonly consume excess amounts of dietary fructose. Added fructose has been shown to have an adverse impact on metabolic health, including increased insulin resistance and type 2 diabetes (T2D) risk. However, the mechanisms that link dietary fructose and metabolic health are poorly understood. Malabsorption or incomplete metabolism of fructose in the small intestine is common in the population. Excess fructose reaches the colon where it may change the structure and function of the gut microbiome, alter bacterial metabolites and trigger inflammatory responses impacting T2D risk. To elucidate whether commonly consumed levels of dietary fructose influence metabolic outcomes through altering the gut microbiome, the research team will randomize 30 participants to a controlled cross-over dietary intervention, in which the participants will consume 12-day isocaloric, added fructose or glucose diets (25% of total calories) separated by a 10-day controlled diet washout period.

Read full original descriptionShow less

The research team aims to:

1. Determine the relationships between high fructose consumption, the gut microbiome and metabolic risk. 2. Characterize the causal role(s) that fructose-induced alterations to the gut microbiome have on metabolic risk using a germ-free mouse model.

The research team will measure 1) microbiota community structure and function via metagenomic sequencing of stool, 2) fecal metabolites via targeted and untargeted metabolomics, 3) anthropometrics, 4) insulin resistance, serum markers of T2D risk and inflammatory cytokines, 5) fecal microbial carbohydrate oxidation capacity and 6) liver fat via MRI elastography. The research team will use novel statistical approaches, including Distributed Lag Modeling, to understand the complex relationships between diet, the microbiome, metabolites and health outcomes.

The research team will then conduct controlled dietary interventions and fecal microbiome transplantation studies in germ-free mice. Donor fecal samples from human participants in both the glucose and fructose arms of the clinical intervention will be transplanted into germ-free and colonized mice to establish a causal relationship between fructose-induced changes to the gut microbiome, liver fat and metabolic and inflammatory changes known to increase risk for T2D.

The research team aims to comprehensively assess the structural and functional changes to the gut microbiome brought about by a high fructose diet. Determining the impact of excess fructose on the microbiome will help identify novel means by which fructose contributes to metabolic disease risk. In addition to identifying strategies to improve metabolic health in adults, data from this proposal could help inform targeted approaches to mitigate future disease risk in vulnerable populations that consume high levels of fructose, such as children.

The 2 groups in the trial

Fructose Dietary then Glucose DietaryTreatment being tested
Participants that will be randomized to the 12-day isocaloric weight-maintaining high fructose diet, then will change to the 12-day isocaloric weight-maintaining high glucose diet after a 10-day washout period.
Treatment: Fructose and glucose
Glucose Dietary then Fructose DietaryTreatment being tested
Participants that will be randomized to the 12-day isocaloric weight-maintaining high glucose diet, then will change to the12-day isocaloric weight-maintaining high fructose diet after a 10-day washout period.
Treatment: Fructose and glucose