Beetroot juice may help prediabetes – study tests effects with and without metformin

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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