Fructose Intestinal Gluconeogenesis (FIG)

March 4, 2026 updated by: Jean-marc Schwarz, Touro University, California

Fructose Metabolism Effects on the Liver: Unraveling the Role of Defective Intestinal GNG in Individuals With Obesity

This study will test the hypothesis that within a defined range of fructose intake, the ability to convert fructose to glucose (via gluconeogenesis) in the small intestine plays a protective role for the liver, shielding it from the deleterious effects of fructose. We will investigate whether this protective effect of the intestine is impaired in individuals with obesity.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Qualified participants will undergo a sugar tolerance test at baseline and then randomized to undergo four separate outpatient tracer/feeding studies in a crossover fashion. After an overnight fast, a six-hour fed tracer study will be initiated, during which participants will consume liquid meals containing stable isotopes at regular intervals and receive other isotopes intravenously. Meal composition will differ only by fructose content (High vs. Low) and tracer (oral vs. intravenous 13C-labeled fructose). Blood and urine samples will be collected frequently throughout the study. Each visit will be performed approximately three weeks apart. Vital signs and anthropometrics will be measured at each clinic visit.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • California
      • Vallejo, California, United States, 95492
        • Recruiting
        • Touro University California
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • BMI 30 to 38 kg/m2 (obese group) or BMI 19 to 25 kg/m2 (lean group)

Exclusion Criteria:

  • Pregnancy or lactation within the past six months;
  • Type 1 or 2 diabetes mellitus (including fasting glucose ≥126 mg/dL, HgbA1c ≥6.5%);
  • History of liver disease or AST and ALT 2x above the upper limit of normal;
  • Fasting triglyceride > 300 mg/dl; total cholesterol levels above the 95th percentile for age and sex;
  • Hemoglobin (Hgb) <12.5g/d or hematocrit<3x Hgb value;
  • Report of HIV or hepatitis B or C infection;
  • History of cancer, other than basal cell or squamous cell carcinoma or kidney disease stage 3 or higher or patients currently on dialysis;
  • Use of any anti-diabetic medications or hypolipidemic agents in the past six months;
  • History of surgical procedure for obesity;
  • Change in body weight >5% in the past six months (by self-report);
  • History of other conditions known to affect insulin sensitivity and lipid metabolism (e.g., polycystic ovary syndrome), history of galactosemia, hereditary fructose intolerance, or who test positive for fructose malabsorption at screening;
  • Known intolerance to acetaminophen.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: High fructose meals, oral 13C fructose
Liquid meals will be fed, containing 55% total carbohydrate (16% fructose), 30% fat, 15% protein, and a tracer amount of 13C fructose.
Other: High fructose meal
Liquid meals containing 55% total carbohydrate (16% fructose), 30% fat, 15% protein.
Other: 13C labeled fructose, oral
Tracer amount of 13C labeled fructose administered orally in the meals.
Experimental: High Fructose Meals, IV 13C Fructose
Liquid meals will be fed, containing 55% total carbohydrate (16% fructose), 30% fat, 15% protein. A tracer amount of 13C fructose will be administered intravenously.
Other: High fructose meal
Liquid meals containing 55% total carbohydrate (16% fructose), 30% fat, 15% protein.
Other: 13C labeled fructose, intravenous
Tracer amount of 13C fructose administered intravenously
Experimental: Low fructose meals, oral fructose tracer
Liquid meals will be fed, containing 55% total carbohydrate (6% fructose), 30% fat, 15% protein, and a tracer amount of 13C fructose.
Other: 13C labeled fructose, oral
Tracer amount of 13C labeled fructose administered orally in the meals.
Other: Low fructose meal
55% total carbohydrate (6% fructose), 30% fat, 15% protein.
Experimental: Low fructose meals, IV 13C fructose tracer
Liquid meals will be fed, containing 55% total carbohydrate (6% fructose), 30% fat, 15% protein. A tracer amount of 13C fructose will be administered intravenously.
Other: 13C labeled fructose, intravenous
Tracer amount of 13C fructose administered intravenously
Other: Low fructose meal
55% total carbohydrate (6% fructose), 30% fat, 15% protein.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Fru-GNG
Time Frame: 6 hours
Total amount of fructose converted to glucose
6 hours
Fru-hGNG
Time Frame: 6 hours
Amount of fructose converted to glucose in the liver
6 hours
Fru-iGNG
Time Frame: 6 hours
Amount of fructose converted to glucose in the intestine
6 hours
De novo lipogenesis (DNL)
Time Frame: 6 hours
Percent of newly synthesized palmitate
6 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Touro University, California

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Grace M Jones, PhD, Touro University, California
  • Principal Investigator: Jean-Marc Schwarz, PhD, Touro University, California

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
March 2, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2030

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2030

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 30, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 30, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 6, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 6, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • M-2624
  • R01DK140477 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The de-identified clinical and laboratory data set will be made available upon request to academic investigators.

IPD Sharing Time Frame

Study data will be made available for at least 5 years from publication of the primary manuscript.

IPD Sharing Access Criteria

Academic investigators may request data and supporting information upon request to the PI.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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