Dolopikou CF(1), Kourtzidis IA(1), Margaritelis NV(1)(2), Vrabas IS(1), Koidou I(1), Kyparos A(1), Theodorou AA(3), Paschalis V(3)(4), Nikolaidis MG(5). Author information:
(1)School of Physical Education and Sport Science at Serres, Aristotle
University of Thessaloniki, Agios Ioannis, 62110, Serres, Greece.
(2)Intensive Care Unit, 424 General Military Hospital of Thessaloniki,
Thessaloniki, Greece.
(3)Department of Health Sciences, School of Sciences, European University
Cyprus, Nicosia, Cyprus.
(4)School of Physical Education and Sport Science, National and Kapodistrian
University of Athens, Athens, Greece.
(5)School of Physical Education and Sport Science at Serres, Aristotle
University of Thessaloniki, Agios Ioannis, 62110, Serres, Greece.
[Email]
PURPOSE: Older individuals suffer from low NADH levels. We have previously shown that nicotinamide riboside [NR; a NAD(P)(H) precursor] administration impaired exercise performance in young rats. It has been suggested that supplementation of redox agents exerts ergogenic effect only in deficient individuals. We hypothesized that old individuals would more likely benefit from NR supplementation. We investigated the effect of acute NR supplementation on redox homeostasis and physical performance in young and old individuals.
METHODS: Twelve young and twelve old men received NR or placebo in a double-blind cross-over design. Before and 2 h after NR or placebo supplementation, blood and urine samples were collected, while physical performance (VO2max, muscle strength, and fatigue) was assessed after the second blood sample collection.
RESULTS: At rest, old individuals exhibited lower erythrocyte NAD(P)H levels, higher urine F2-isoprostanes and lower erythrocyte glutathione levels compared to young (P < 0.05). NR supplementation increased NADH (51% young; 59% old) and NADPH (32% young; 38% old) levels in both groups (P < 0.05), decreased F2-isoprostanes by 18% (P < 0.05), and tended to increase glutathione (P = 0.078) only in the old. NR supplementation did not affect VO2max and concentric peak torque, but improved isometric peak torque by 8% (P = 0.048) and the fatigue index by 15% (P = 0.012) in the old. In contrast, NR supplementation did not exert any redox or physiological effect in the young.
CONCLUSIONS: NR supplementation increased NAD(P)H levels, decreased oxidative stress, and improved physical performance only in old subjects, substantiating that redox supplementation may be beneficial only in individuals with antioxidant deficiencies.
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