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Caloric Restriction (CR) Plus High-Nitrate Beetroot Juice Does Not Amplify CR-Induced Metabolic Adaptation and Improves Vascular and Cognitive Functions in Overweight Adults: A 14-Day Pilot Randomised Trial

Lookup NU author(s): Christina Koechl, Dr Oliver Shannon



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Caloric restriction (CR) and dietary nitrate supplementation are nutritional interventions with pleiotropic physiological functions. This pilot study investigates the combined effects of CR and nitrate-rich beetroot juice (BRJ) on metabolic, vascular, and cognitive functions in overweight and obese middle-aged and older adults. This was a two-arm, parallel randomized clinical trial including 29 participants allocated to CR + BRJ (n = 15) or CR alone (n = 14) for 14 days. Body composition, resting energy expenditure (REE), and hand-grip strength were measured. Resting blood pressure (BP) and microvascular endothelial function were measured, and Trail-Making Test A and B were used to assess cognitive function. Salivary nitrate and nitrite, and urinary nitrate and 8-isoprostane concentrations were measured. Changes in body composition, REE, and systolic and diastolic BP were similar between the two interventions (p > 0.05). The CR + BRJ intervention produced greater changes in average microvascular flux (p = 0.03), NO-dependent endothelial activity (p = 0.02), and TMT-B cognitive scores (p = 0.012) compared to CR alone. Changes in urinary 8-isoprostane were greater in the CR + BRJ group (p = 0.02), and they were inversely associated with changes in average microvascular flux (r = −0.53, p = 0.003). These preliminary findings suggest that greater effects on vascular and cognitive functions could be achieved by combining CR with dietary nitrate supplementation.

Publication metadata

Author(s): Alharbi M, Chiurazzi M, Nasti G, Muscariello E, Mastantuono T, Koechl C, Stephan BCM, Shannon OM, Colantuoni A, Siervo M

Publication type: Article

Publication status: Published

Journal: Nutrients

Year: 2023

Volume: 15

Issue: 4

Print publication date: 10/02/2023

Acceptance date: 08/02/2023

Date deposited: 14/07/2023

ISSN (electronic): 2072-6643

Publisher: MDPI AG


DOI: 10.3390/nu15040890


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Funder referenceFunder name
Newcastle University
University of Naples Federico II