Beetroot juice to boost blood vessels, insulin sensitivity, and exercise in prediabetes on vs. off metformin

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a randomized, double-blind cross-over study involving 24 adults with prediabetes. Participants will receive inorganic nitrate (beetroot juice) or nitrate-depleted placebo in alternating periods, and will be categorized as metformin users or metformin-naïve. The study will measure vascular function, VO2 peak, lactate threshold, glucose tolerance, and endurance during exercise. It aims to see if nitrate supplementation can enhance vascular and metabolic responses without adverse effects in this population.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Individuals who can communicate meaningfully with the investigator and can provide written consent.
* Confirmed prediabetic individuals (ages 18-60 years old) (2-hour glucose of 140-199 mg/dL following OGTT test or HbA1c between 5.7-6.4% tested on two occasions within 6 months).
* Taking metformin (stable dose for at least a week) or naïve to metformin
* Sedentary (\<1 day/week of structured exercise)
* Be able to perform exercise on a cycle ergometer without assistance
* Stable medication regimen for the last 6 months
* If female, have a normal menstrual cycle

Exclusion Criteria:

* Estimated Glomerular filtration rate (GFR) ≤ 45
* Body mass index ≥ 40 Kg/m2
* HbA1c \> 6.4%
* Smokers within the last 5 years
* Has experienced significant weight loss \~3 kg in the last three months or is taking any weight loss drugs
* Current medical condition that prohibits exercising at high intensities
* Currently on hormone replacement of any kind
* History of myocardial infarction, cerebrovascular event, acute or unstable disease other than pre-diabetes or obesity
* Currently taking any of the following medications (calcium channel blockers, statins, ACE or renin inhibitors, angiotensin receptor blockers, organic nitrates (e.g., nitroglycerine) or recent regular use of inorganic nitrates, alpha- or beta-blockers, diuretics, proton pump inhibitors, PDE-5 inhibitors (e.g.,: Cialis, Viagra), or xanthine oxidase inhibitors (e.g.,: Allopurinol))
* Oral antibiotic use within the previous four weeks, including over-the-counter antibacterial mouthwash or a mouthwash containing chlorhexidine and unwilling to discontinue use
* Oral cancer/severe oral disease
* Uncontrolled hypertension (\>140/90)
* Had hysterectomy or oophorectomy
* Fetuses, neonates, children, prisoners, cognitively impaired, non-English speaking participants

Where it's running

• University of Virginia
  Charlottesville, Virginia, United States Recruiting

Study contacts

• Principal investigator: Jason Allen, PhD — University of Virginia
• Study coordinator: Money Ghimire, M.S
• Email: eta8xd@uvahealth.org
• Phone: 4342438677

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.