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Active, not recruitingNCT04168372Updated Jul 10, 2026

Fructose: Substrate, Stimulus, or Both?

An interventional study of High fructose, fructose labeled meal and High fructose, pyruvate labeled meal in Insulin Resistance, Insulin Sensitivity and Pre Diabetes, sponsored by Touro University, California. Active, not recruiting at 1 site in United States. Open to participants aged 20 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-10.

Sponsored by Touro University, California · Not applicable, Interventional, and Basic science

Phase
Not applicable
Study type
Interventional
Enrollment
35
Allocation
Randomized
Ages
20 Years to 55 Years
Sex
All
01

Study summary

This objective of this study is to use sensitive methodology under controlled conditions to investigate the mechanisms by which fructose consumption contributes to excess fatty acid synthesis and elevations in blood glucose levels following consumption of meals containing fructose.

02

Conditions studied

  • Insulin Resistance
  • Insulin Sensitivity
  • Pre Diabetes

Keywords

  • Fructose
  • Glucose
  • Lipogenesis
03

In context

Insulin Resistance

1,960 studies on the registry are indexed under Insulin Resistance; 306 are open to participants now.

This study's enrollment of 35 is below the median of 40 across 1,536 interventional studies indexed under Insulin Resistance.

Browse Insulin Resistance studies →

Lead sponsor

Touro University, California is the lead sponsor of 6 studies on the registry; 2 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
20 Years to 55 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • Body Mass Index 22 to 35 kg/m2
  • Prediabetic (HbA1c 5.7% to 6.5%) or hyperinsulinemic (fasting insulin ≥12 µIU/mL) but non-diabetic (fasting glucose \<126mg/dL and HbA1c \< 6.5%) ; or normal control (fasting insulin \<10 µIU/mL, fasting glucose \<100 mg/dL, and HbA1c \< 5.7%)

Exclusion criteria

Exclusion Criteria:

  • Pregnancy or lactation within the past six months
  • Type 1 or 2 diabetes mellitus
  • History of liver disease or aspartate aminotransferase (AST) and alanine aminotransferase (ALT) 2x the upper limit of normal (ULN);
  • Fasting triglyceride or total cholesterol levels above 95th percentile for age and sex;
  • Hemoglobin or hematocrit below the lower limit of normal for sex;
  • Report of hepatitis or HIV infection;
  • History of cancer, use of any anti-diabetic medications or hypolipidemic agents in the past six months;
  • History of surgical procedure for obesity;
  • Self-reported change in body weight >5% in the past six months;
  • History of other conditions known to affect insulin sensitivity and lipid metabolism;
  • Known intolerance to acetaminophen or components of the liquid test meals.
05

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Randomized
Intervention model
Crossover assignment
Masking
Triple (Participant, Investigator, Outcomes assessor)
Enrollment
35 participants (actual)

Study arms

  • Experimental
    High fructose meal, with fructose label

    2-13C fructose incorporated into a meal with high fructose content

    Other: High fructose, fructose labeled meal

  • Experimental
    High fructose meal, with pyruvate label

    2-13C pyruvate incorporated into a meal with high fructose content

    Other: High fructose, pyruvate labeled meal

  • Experimental
    Low fructose meal, with fructose label

    2-13C fructose incorporated into a meal with low fructose content

    Other: Low fructose, fructose labeled meal

  • Experimental
    Low fructose meal, with pyruvate label

    2-13C pyruvate incorporated into a meal with low fructose content

    Other: Low fructose, pyruvate labeled meal

Interventions

  • OtherHigh fructose, fructose labeled meal

    Liquid meal containing high fructose (16% of energy), labeled with 2-13C fructose

  • OtherHigh fructose, pyruvate labeled meal

    Liquid meal containing high fructose (16% of energy), labeled with 2-13C pyruvate

  • OtherLow fructose, fructose labeled meal

    Liquid meals containing low fructose (6% of energy), labeled with 2-13C fructose

  • OtherLow fructose, pyruvate labeled meal

    Liquid meal containing low fructose (6% of energy), labeled with 2-13C pyruvate

06

What researchers measure

Primary outcomes

  1. Hepatic fractional de novo lipogenesis in triglyceride rich lipoprotein (TRL)

    Measured by the detection of 13C carbons in TRL-palmitate from administered 13C labeled pyruvate or 13C labeled fructose.

    Time frame: 6 hours

  2. Rate of appearance of UDP-glucose

    An estimate of hepatic glycogen flux measured by administration of D1 galactose and acetaminophen

    Time frame: 6 hours

  3. Rate of appearance of blood glucose from gluconeogenesis

    Measured by the dilution method of labeled glucose

    Time frame: 6 hours

Secondary outcomes

  1. Serum triglyceride concentration

    Fasting and postprandial serum triglyceride levels

    Time frame: 6 hours

  2. Serum glucose concentration

    Fasting and postprandial serum triglyceride levels

    Time frame: 6 hours

  3. Serum lactate concentration

    Fasting and postprandial serum lactate levels

    Time frame: 6 hours

  4. Serum insulin concentration

    Fasting and postprandial insulin levels

    Time frame: 6 hours

  5. Serum free fatty acid concentration

    Fasting and postprandial fatty acid levels

    Time frame: 6 hours

  6. Enteral (chylomicron) fractional de novo lipogenesis (DNL)

    Measured by the detection of 13C carbons in chylomicron-palmitate from administered 13C labeled pyruvate or 13C labeled fructose.

    Time frame: 6 hours

  7. Hepatic (VLDL) fractional de novo lipogenesis (DNL)

    Measured by the detection of 13C carbons in VLDL-palmitate from administered 13C labeled pyruvate or 13C labeled fructose.

    Time frame: 6 hours

  8. Extrasplanchnic fructose

    Calculated using total plasma fructose, plasma 2-13C fructose enrichment, and endogenous fructose production

    Time frame: 6 hours

  9. Whole body fructose oxidation

    Measured by 13C atom % excess in exhaled breath, and VCO2 by indirect calorimetry

    Time frame: 6 hours

07

Study locations

1 site
  • Touro University California
    Vallejo, California 94592, United States
08

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 10, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT04168372
Lead sponsor
Touro University, California
Responsible party
Sponsor
First posted
Nov 19, 2019
Start date
Sep 15, 2019
Primary completion
Dec 31, 2026 (estimated)
Completion
Jul 20, 2027 (estimated)
Last update
Jul 10, 2026

Study contacts

Jean-Marc Schwarz, PhD
principal investigator · Touro University, California

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.

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