deltatrials
Completed INTERVENTIONAL NCT00065676

Investigating the Use of Quercetin on Glucose Absorption in Obesity, and Obesity With Type 2 Diabetes

Inhibition of Intestinal Glucose Absorption by the Bioflavonoid Quercetin in the Obese and in Obese Type 2 Diabetics

Sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Conditions Diabetes Obesity
Interventions Placebo Quercetin
Updated 91 times since 2017 Last updated: Apr 30, 2026 Started: Apr 30, 2010 Primary completion: Dec 21, 2015 Completion: Aug 6, 2021
This information is for research purposes only and is not medical advice. Consult a healthcare provider before making any medical decision.

This observational or N/A phase trial investigates Diabetes and Obesity and is currently completed. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) leads this study, which shows 91 recorded versions since 2010 — indicating substantial longitudinal coverage. The change history captured here reflects the iterative nature of clinical trial conduct.

Study Description(click to expand)

Postprandial hyperglycemia and the resultant hyperinsulinemia contribute to the cardiovascular complications seen in obesity and in type 2 diabetes. Epidemiological studies suggest that slow absorption of carbohydrates dampens glucose and insulin peaks, and reduces cardiovascular morbidity. The polyphenol quercetin is the most abundant flavanoid in plant-derived foods, and is sold as a dietary supplement. In vitro, quercetin is a potent and reversible inhibitor of glucose transport by the intestinal glucose transporter GLUT2. In vivo quercetin inhibits post absorptive glucose peaks in obese, diabetic rats. We hypothesize that quercetin blunts intestinal glucose absorption in humans, and attenuates postprandial hyperglycemia. We propose to test, in a double blind placebo controlled study, whether coadministration of 1 or 2 grams of quercetin with glucose will reduce plasma glucose concentrations during a 6 hour oral glucose tolerance test with 3 to 6 grams of 3-O-methyl glucose (3OMG) in non-diabetic obese subjects and in obese type 2 diabetic subjects. The glucose dose may be varied from 0 to 100 grams to better understand the competition between 3OMG and glucose. 3OMG is a non-metabolizable glucose analogue and is excreted unaltered in urine. 3OMG is not found in food and thus glucose absorption can be studies easily without...

Postprandial hyperglycemia and the resultant hyperinsulinemia contribute to the cardiovascular complications seen in obesity and in type 2 diabetes. Epidemiological studies suggest that slow absorption of carbohydrates dampens glucose and insulin peaks, and reduces cardiovascular morbidity. The polyphenol quercetin is the most abundant flavanoid in plant-derived foods, and is sold as a dietary supplement. In vitro, quercetin is a potent and reversible inhibitor of glucose transport by the intestinal glucose transporter GLUT2. In vivo quercetin inhibits post absorptive glucose peaks in obese, diabetic rats. We hypothesize that quercetin blunts intestinal glucose absorption in humans, and attenuates postprandial hyperglycemia. We propose to test, in a double blind placebo controlled study, whether coadministration of 1 or 2 grams of quercetin with glucose will reduce plasma glucose concentrations during a 6 hour oral glucose tolerance test with 3 to 6 grams of 3-O-methyl glucose (3OMG) in non-diabetic obese subjects and in obese type 2 diabetic subjects. The glucose dose may be varied from 0 to 100 grams to better understand the competition between 3OMG and glucose. 3OMG is a non-metabolizable glucose analogue and is excreted unaltered in urine. 3OMG is not found in food and thus glucose absorption can be studies easily without the problem of a high baseline value. The use of 3OMG will provide a more accurate and true measures of glucose absorption. Study subjects will be 19 - 65 years with a body mass index greater than or equal to 30, without complications of diabetes, or on any medication other than oral hypoglycemic agents and aspirin. We will study 16 obese non diabetic subjects and 16 obese type 2 diabetics. Each subject will have 3 oral glucose tolerance tests, and will serve as his or her own control. We will compare the peak plasma glucose concentrations achieved during oral glucose tolerance tests and the area under the curve of plasma glucose to determine whether quercetin inhibits glucose absorption in humans. Such inhibition may partially explain the protective effects of plant derived foods on cardiovascular disease, and enable us to use quercetin or related compounds to dampen intestinal glucose absorption. We will also measure quercetin concentrations in the plasma, in circulating white blood cells and in urine to determine quercetin pharmacokinetics. Additionally, to determine the optimal 3OMG dose, we will study the absorption of glucose and 3OMG, without quercetin, in 12 non-diabetic obese subjects and 12 lean subjects to serve as controls.

Status Flow

~Jan 2017 – ~Mar 2018 · 14 months · monthly snapshot~Mar 2018 – ~Jun 2018 · 3 months · monthly snapshot~Jun 2018 – ~Jul 2018 · 30 days · monthly snapshot~Jul 2018 – ~Aug 2018 · 31 days · monthly snapshot~Aug 2018 – ~Sep 2018 · 31 days · monthly snapshot~Sep 2018 – ~Oct 2018 · 30 days · monthly snapshot~Oct 2018 – ~Nov 2018 · 31 days · monthly snapshot~Nov 2018 – ~Dec 2018 · 30 days · monthly snapshot~Dec 2018 – ~Jan 2019 · 31 days · monthly snapshot~Jan 2019 – ~Mar 2019 · 59 days · monthly snapshot~Mar 2019 – ~Apr 2019 · 31 days · monthly snapshot~Apr 2019 – ~May 2019 · 30 days · monthly snapshot~May 2019 – ~Jun 2019 · 31 days · monthly snapshot~Jun 2019 – ~Aug 2019 · 2 months · monthly snapshot~Aug 2019 – ~Sep 2019 · 31 days · monthly snapshot~Sep 2019 – ~Oct 2019 · 30 days · monthly snapshot~Oct 2019 – ~Nov 2019 · 31 days · monthly snapshot~Nov 2019 – ~Dec 2019 · 30 days · monthly snapshot~Dec 2019 – ~Jan 2020 · 31 days · monthly snapshot~Jan 2020 – ~Feb 2020 · 31 days · monthly snapshot~Feb 2020 – ~Mar 2020 · 29 days · monthly snapshot~Mar 2020 – ~Apr 2020 · 31 days · monthly snapshot~Apr 2020 – ~May 2020 · 30 days · monthly snapshot~May 2020 – ~Jun 2020 · 31 days · monthly snapshot~Jun 2020 – ~Jul 2020 · 30 days · monthly snapshot~Jul 2020 – ~Aug 2020 · 31 days · monthly snapshot~Aug 2020 – ~Sep 2020 · 31 days · monthly snapshot~Sep 2020 – ~Oct 2020 · 30 days · monthly snapshot~Oct 2020 – ~Nov 2020 · 31 days · monthly snapshot~Nov 2020 – ~Dec 2020 · 30 days · monthly snapshot~Dec 2020 – ~Jan 2021 · 31 days · monthly snapshot~Jan 2021 – ~Feb 2021 · 31 days · monthly snapshot~Feb 2021 – ~Mar 2021 · 28 days · monthly snapshot~Mar 2021 – ~Apr 2021 · 31 days · monthly snapshot~Apr 2021 – ~May 2021 · 30 days · monthly snapshot~May 2021 – ~Jun 2021 · 31 days · monthly snapshot~Jun 2021 – ~Sep 2021 · 3 months · monthly snapshot~Sep 2021 – ~Oct 2021 · 30 days · monthly snapshot~Oct 2021 – ~Nov 2021 · 31 days · monthly snapshot~Nov 2021 – ~Dec 2021 · 30 days · monthly snapshot~Dec 2021 – ~Jan 2022 · 31 days · monthly snapshot~Jan 2022 – ~Feb 2022 · 31 days · monthly snapshot~Feb 2022 – ~Mar 2022 · 28 days · monthly snapshot~Mar 2022 – ~Apr 2022 · 31 days · monthly snapshot~Apr 2022 – ~May 2022 · 30 days · monthly snapshot~May 2022 – ~Jun 2022 · 31 days · monthly snapshot~Jun 2022 – ~Jul 2022 · 30 days · monthly snapshot~Jul 2022 – ~Sep 2022 · 2 months · monthly snapshot~Sep 2022 – ~Nov 2022 · 2 months · monthly snapshot~Nov 2022 – ~Dec 2022 · 30 days · monthly snapshot~Dec 2022 – ~Jan 2023 · 31 days · monthly snapshot~Jan 2023 – ~Feb 2023 · 31 days · monthly snapshot~Feb 2023 – ~Mar 2023 · 28 days · monthly snapshot~Mar 2023 – ~Apr 2023 · 31 days · monthly snapshot~Apr 2023 – ~May 2023 · 30 days · monthly snapshot~May 2023 – ~Jun 2023 · 31 days · monthly snapshot~Jun 2023 – ~Jul 2023 · 30 days · monthly snapshot~Jul 2023 – ~Aug 2023 · 31 days · monthly snapshot~Aug 2023 – ~Sep 2023 · 31 days · monthly snapshot~Sep 2023 – ~Oct 2023 · 30 days · monthly snapshot~Oct 2023 – ~Nov 2023 · 31 days · monthly snapshot~Nov 2023 – ~Dec 2023 · 30 days · monthly snapshot~Dec 2023 – ~Jan 2024 · 31 days · monthly snapshot~Jan 2024 – ~Feb 2024 · 31 days · monthly snapshot~Feb 2024 – ~Mar 2024 · 29 days · monthly snapshot~Mar 2024 – ~Apr 2024 · 31 days · monthly snapshot~Apr 2024 – ~May 2024 · 30 days · monthly snapshot~May 2024 – ~Jun 2024 · 31 days · monthly snapshot~Jun 2024 – ~Jul 2024 · 30 days · monthly snapshot~Jul 2024 – ~Aug 2024 · 31 days · monthly snapshot~Aug 2024 – ~Sep 2024 · 31 days · monthly snapshot~Sep 2024 – ~Oct 2024 · 30 days · monthly snapshot~Oct 2024 – ~Nov 2024 · 31 days · monthly snapshot~Nov 2024 – ~Dec 2024 · 30 days · monthly snapshot~Dec 2024 – ~Jan 2025 · 31 days · monthly snapshot~Jan 2025 – ~Feb 2025 · 31 days · monthly snapshot~Feb 2025 – ~Mar 2025 · 28 days · monthly snapshot~Mar 2025 – ~Apr 2025 · 31 days · monthly snapshot~Apr 2025 – ~May 2025 · 30 days · monthly snapshot~May 2025 – ~Jun 2025 · 31 days · monthly snapshot~Jun 2025 – ~Jul 2025 · 30 days · monthly snapshot~Jul 2025 – ~Aug 2025 · 31 days · monthly snapshot~Aug 2025 – ~Sep 2025 · 31 days · monthly snapshot~Sep 2025 – ~Oct 2025 · 30 days · monthly snapshot~Oct 2025 – ~Nov 2025 · 31 days · monthly snapshot~Nov 2025 – ~Dec 2025 · 30 days · monthly snapshot~Dec 2025 – ~Jan 2026 · 31 days · monthly snapshot~Jan 2026 – ~Feb 2026 · 31 days · monthly snapshot~Feb 2026 – ~Apr 2026 · 3 months · monthly snapshotApr 28, 2026 – May 4, 2026 · 6 days · daily APIMay 4, 2026 – present · 3 months · daily API

Change History

91 versions recorded

  1. May 4, 2026 — Present [daily]

    Completed

  2. Apr 28, 2026 — May 4, 2026 [daily]

    Completed

    Phase: PHASE2 → None

  3. Feb 2026 — Apr 2026 [monthly]

    Completed PHASE2

  4. Jan 2026 — Feb 2026 [monthly]

    Completed PHASE2

  5. Dec 2025 — Jan 2026 [monthly]

    Completed PHASE2

▶ Show 86 earlier versions

  1. Nov 2025 — Dec 2025 [monthly]

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    Status: Recruiting → Completed

  50. Jun 2021 — Sep 2021 [monthly]

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  85. Mar 2018 — Jun 2018 [monthly]

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  86. Jan 2017 — Mar 2018 [monthly]

    Recruiting PHASE2

    First recorded

Apr 2010

Trial started

Per CT.gov start date — pre-dates our first snapshot

Eligibility Summary

Quercetin is a compound naturally found in various foods. It may have some role in the treatment of obesity and diabetes. The purpose of this study is to investigate research volunteers with obesity or obesity with type 2 diabetes to determine whether quercetin affects the way glucose is absorbed by the body. Thirty two participants aged 19 to 65 who are considered to be medically obese or obese with type 2 diabetes will be enrolled in this study. Before the onset of treatment, they will undergo a medical history, physical exam, blood work, and urinalysis. During the study, participants will be given an oral glucose tolerance test three times; during these tests they will receive 1 or 2 grams of quercetin, or placebo. Researchers will collect blood samples and analyze the effect of the treatment on blood glucose.

Contact Information

Sponsor contact:
  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Data source: ClinicalTrials.gov

For direct contact, visit the study record on ClinicalTrials.gov .

Study Locations