Recruiting

Zinc

Sponsor:

University of Maryland, Baltimore

Code:

NCT05835037

Conditions

Prediabetic State

Hyperglycemia

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Not accepted

Interventions

Zinc Gluconate 30 MG

Placebo

Study Details

Brief summary:

The purpose of this investigation is to evaluate the impact of zinc supplementation on fasting glucose levels, hemoglobin A1c (HbA1c), and other indices of glucose homeostasis in individuals with prediabetes. The investigators hypothesize that prediabetic subjects receiving zinc will demonstrate a greater decrease in HbA1c and blood glucose compared to prediabetic subjects receiving placebo.

Specific Aim: Conduct a prospective, double-blind randomized clinical trial comparing the effects of 12 months of zinc supplementation (zinc gluconate 30 milligram \[mg\] per day) versus placebo on glucose homeostasis. Based upon expected effect size and power calculations, and anticipating a 20% drop-out rate, the investigators will study 200 prediabetic subjects (100 per group) using a 1:1 randomization design. HbA1c, fasting plasma glucose, and other measures will be obtained at 0, 6, and 12 months and will be compared between zinc supplementation and placebo groups.

Conditions

Prediabetic State

Hyperglycemia

Study ID

NCT05835037

Start date

Feb 16, 2024

Status verified date

Jul, 2026

Completion date

Jul, 2028

Anticipated

Primary completion date

Jul, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Amish men or women who are 18 to 80 years old
  • Prediabetes (HgbA1c = 5.7-6.4% or fasting glucose levels 100-125 mg/dL)

Exclusion Criteria:

  • Pregnant
  • Currently breastfeeding
  • History of severe gastrointestinal disorders or upper gastrointestinal surgery
  • Has hemochromatosis, cancer, liver disease, kidney disease, cardiovascular disease, or other coexisting malignancy
  • Hemoglobin < 12.5 g/dl (male) or < 11 g/dl (female)
  • Severe hypertension (blood pressure > 160/95 mm Hg)
  • Has a creatinine greater than 2.0 mg/dl, aspartate aminotransferase (AST) or alanine transaminase (ALT) greater than 2 times the upper limit of normal, hematocrit (Hct) less than 32%, or thyroid-stimulating hormone (TSH) less than 0.4 or greater than 5.5 milli-international units (mIU) per liter.
  • At the discretion of the study physician or PI, taking medications that affect the outcomes of the study including, but not limited to, corticosteroids, anti-psychotic agents, protease inhibitors, oral contraceptives, estrogens, niacin, and some classes of antidepressants, statins, and antihypertensive medications
  • Zinc hypersensitivity
  • Use of denture adhesive containing zinc
  • Taking other medications or zinc-containing supplements and is unwilling or cannot safely, in the opinion of the study physician, discontinue their use at least 2 weeks prior to protocol initiation
  • Any other condition that would, in the opinion of the investigator, place them at an unacceptable risk or render them unable to meet the requirements of the protocol.

Study Design

Enrollment

200 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Zinc treatment

Research subjects administered zinc gluconate for 1 year (one 30 mg tablet per day)

placebo comparator: Placebo

Research subjects administered placebo for 1 year (1 tablet per day)

Interventions

Zinc Gluconate 30 MG

Participants will take one tablet per day (30 mg Zinc gluconate) for 1 year

Placebo

Participants will take one placebo tablet per day for 1 year

Primary outcome measure

  • Zinc-dependent effect on fasting glucose levels at 1 year [ Time Frame: 1 year ]
  • Zinc-dependent effect on HbA1c at 1 year [ Time Frame: 1 year ]

Central Contacts and Locations

Central contacts

Toni I Pollin, PhD

410-706-1630tpollin@som.umaryland.edu

Hilary B Whitlatch, MD

443-682-6800hwhitlatch@som.umaryland.edu

Locations

Amish Research Clinic

Recruiting

Lancaster, Pennsylvania, United States, 17602

Contacts

Kamah Woelfel, RN

717-392-4948KWoelfel@som.umaryland.edu

More Information

Sponsor

University of Maryland, Baltimore

Last update posted

Jul 10, 2026

Last verified

Jul, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Maryland, Baltimore on 2026-07-10.