title: Dietary quercetin supplementation is not ergogenic in untrained men.
abstract: Quercetin supplementation increases muscle oxidative capacity and endurance in mice, but its ergogenic effect in humans has not been established. Our study investigates the effects of short-duration chronic quercetin supplementation on muscle oxidative capacity; metabolic, perceptual, and neuromuscular determinants of performance in prolonged exercise; and cycling performance in untrained men. Using a double-blind, pretest-posttest control group design, 30 recreationally active, but not endurance-trained, young men were randomly assigned to quercetin and placebo groups. A noninvasive measure of muscle oxidative capacity (phosphocreatine recovery rate using magnetic resonance spectroscopy), peak oxygen uptake (Vo(2peak)), metabolic and perceptual responses to submaximal exercise, work performed on a 10-min maximal-effort cycling test following the submaximal cycling, and voluntary and electrically evoked strength loss following cycling were measured before and after 7-16 days of supplementation with 1 g/day of quercetin in a sports hydration beverage or a placebo beverage. Pretreatment-to-posttreatment changes in phosphocreatine recovery time constant, Vo(2peak,) substrate utilization, and perception of effort during submaximal exercise, total work done during the 10-min maximal effort cycling trial, and voluntary and electrically evoked strength loss were not significantly different (P > 0.05) in the quercetin and placebo groups. Short duration, chronic dietary quercetin supplementation in untrained men does not improve muscle oxidative capacity; metabolic, neuromuscular and perceptual determinants of performance in prolonged exercise; or cycling performance. The null findings indicate that metabolic and physical performance consequences of quercetin supplementation observed in mice should not be generalized to humans.
authors.affiliation: Department of Kinesiology, Ramsey Center, 330 River Road, Univ. of Georgia Athens, GA 30602-6554. kcureton@uga.edu
authors.forename: Kirk J
authors.initials: KJ
authors.lastname: Cureton
authors.forename: Phillip D
authors.initials: PD
authors.lastname: Tomporowski
authors.forename: Arpit
authors.initials: A
authors.lastname: Singhal
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Pasley
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Bigelman
authors.forename: Kathleen
authors.initials: K
authors.lastname: Lambourne
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Trilk
authors.forename: Kevin K
authors.initials: KK
authors.lastname: McCully
authors.forename: Maurice J
authors.initials: MJ
authors.lastname: Arnaud
authors.forename: Qun
authors.initials: Q
authors.lastname: Zhao
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000284:Administration, Oral; D000328:Adult; D001628:Beverages; D001642:Bicycling; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004558:Electric Stimulation; D004734:Energy Metabolism / Q000187:drug effects*; D015444:Exercise; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005990:Glycerol / Q000097:blood; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D053580:Muscle Strength / Q000187:drug effects; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010725:Phosphocreatine / Q000097:blood; D011794:Quercetin / Q000008:administration & dosage* / Q000097:blood; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D010725:Phosphocreatine; D011794:Quercetin; D005990:Glycerol; D020155:3-Hydroxybutyric Acid