title: Dietary nitrate does not affect physical activity or outcomes in healthy older adults in a randomized, cross-over trial.
abstract: Although dietary nitrate (NO3-) ingestion appears to enhance exercise capacity and performance in young individuals, inconclusive findings have been reported in older people. Therefore, we conducted a double-blind, crossover randomized clinical trial using beetroot juice in older healthy participants, who were classified as normal weight and overweight. We tested whether consumption of beetroot juice (a rich source of NO3-) for 1 week would increase nitric oxide bioavailability via the nonenzymatic pathway and enhance (1) exercise capacity during an incremental exercise test, (2) physical capability, and (3) free-living physical activity. Twenty nonsmoking, healthy participants between 60 and 75 years of age and with a body mass index of 20.0 to 29.9 kg/m2were included. Presupplementation and postsupplementation resting, submaximal, maximal, and recovery gas exchanges were measured. Physical capability was measured by hand-grip strength, time-up-and-go, repeated chair rising test, and 10-m walking speed. Free-living physical activity was assessed by triaxal accelerometry. Changes in urinary and plasmaNO3-concentrations were measured by gas chromatography-mass spectrometry. Nineteen participants (male-to-female ratio, 9:10) completed the study.Beetroot juice increased significantly both plasma and urinary NO3-concentrations (P<.001) when compared with placebo. Beetroot juice did not influence resting or submaximal and maximal oxygen consumption during the incremental exercise test. In addition, measures of physical capability and physical activity levels measured in free-living conditions were not modified by beetroot juice ingestion. The positive effects of beetroot juice ingestion on exercise performance seen in young individuals were not replicated in healthy, older adults. Whether aging represents a modifier of the effects of dietary NO3-on muscular performance is not known, and mechanistic studies and larger trials are needed to test this hypothesis.
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK. Electronic address: mario.siervo@ncl.ac.uk.
authors.forename: Mario
authors.initials: M
authors.lastname: Siervo
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK.
authors.forename: Clio
authors.initials: C
authors.lastname: Oggioni
authors.affiliation: Institute of Cellular Medicine, MoveLab, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK; RCUK Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
authors.forename: Djordje G
authors.initials: DG
authors.lastname: Jakovljevic
authors.affiliation: Institute of Cellular Medicine, MoveLab, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK; RCUK Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Trenell
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK; RCUK Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
authors.forename: John C
authors.initials: JC
authors.lastname: Mathers
authors.affiliation: Institute of Cellular Medicine, MoveLab, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
authors.forename: David
authors.initials: D
authors.lastname: Houghton
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK.
authors.forename: Carlos
authors.initials: C
authors.lastname: Celis-Morales
authors.affiliation: Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK.
authors.forename: Ammar W
authors.initials: AW
authors.lastname: Ashor
authors.affiliation: Centre for Sport and Exercise Science, Sheffield Hallam University, Sheffield, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Ruddock
authors.affiliation: Centre for Sport and Exercise Science, Sheffield Hallam University, Sheffield, UK.
authors.forename: Mayur
authors.initials: M
authors.lastname: Ranchordas
authors.affiliation: Centre for Sport and Exercise Science, Sheffield Hallam University, Sheffield, UK.
authors.forename: Markos
authors.initials: M
authors.lastname: Klonizakis
authors.affiliation: Human Nutrition Unit, Department of Oncology, Faculty of Medicine, Dentistry and Health, University of Sheffield, Sheffield, S10 2RX, UK.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Williams
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D027461:Beta vulgaris / Q000737:chemistry*; D015992:Body Mass Index; D018592:Cross-Over Studies; D004032:Diet; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000378:metabolism / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology*; D010936:Plant Extracts / Q000494:pharmacology; D012016:Reference Values
chemical_list: D009566:Nitrates; D010936:Plant Extracts; D009569:Nitric Oxide
keywords: Aging; Exercise; Inorganic nitrate; Nitric oxide; Oxygen consumption