Vitamin C and E supplementation hampers cellular adaptation to endurance training in humans: a double-blind, randomised, controlled trial.
In this double-blind, randomised, controlled trial, we investigated the effects of vitamin C and E supplementation on endurance training adaptations in humans. Fifty-four young men and women were randomly allocated to receive either 1000 mg of vitamin C and 235 mg of vitamin E or a placebo daily for 11 weeks. During supplementation, the participants completed an endurance training programme consisting of three to four sessions per week (primarily of running), divided into high-intensity interval sessions [4-6 × 4-6 min; >90% of maximal heart rate (HRmax)] and steady state continuous sessions (30-60 min; 70-90% of HRmax). Maximal oxygen uptake (VO2 max ), submaximal running and a 20 m shuttle run test were assessed and blood samples and muscle biopsies were collected, before and after the intervention. Participants in the vitamin C and E group increased their VO2 max (mean ± s.d.: 8 ± 5%) and performance in the 20 m shuttle test (10 ± 11%) to the same degree as those in the placebo group (mean ± s.d.: 8 ± 5% and 14 ± 17%, respectively). However, the mitochondrial marker cytochrome c oxidase subunit IV (COX4) and cytosolic peroxisome proliferator-activated receptor-γ coactivator 1 α (PGC-1α) increased in the m. vastus lateralis in the placebo group by 59 ± 97% and 19 ± 51%, respectively, but not in the vitamin C and E group (COX4: -13 ± 54%; PGC-1α: -13 ± 29%; P ≤ 0.03, between groups). Furthermore, mRNA levels of CDC42 and mitogen-activated protein kinase 1 (MAPK1) in the trained muscle were lower in the vitamin C and E group than in the placebo group (P ≤ 0.05). Daily vitamin C and E supplementation attenuated increases in markers of mitochondrial biogenesis following endurance training. However, no clear interactions were detected for improvements in VO2 max and running performance. Consequently, vitamin C and E supplementation hampered cellular adaptations in the exercised muscles, and although this did not translate to the performance tests applied in this study, we advocate caution when considering antioxidant supplementation combined with endurance exercise.
Norwegian School of Sport Sciences, PB 4014 Ullevål Stadion, 0806 Oslo, Norway.  goran.paulsen@olympiatoppen.no.
Gøran
G
Paulsen
Kristoffer T
KT
Cumming
Geir
G
Holden
Jostein
J
Hallén
Bent Ronny
BR
Rønnestad
Ole
O
Sveen
Arne
A
Skaug
Ingvild
I
Paur
Nasser E
NE
Bastani
Hege Nymo
HN
Østgaard
Charlotte
C
Buer
Magnus
M
Midttun
Fredrik
F
Freuchen
Havard
H
Wiig
Elisabeth Tallaksen
ET
Ulseth
Ina
I
Garthe
Rune
R
Blomhoff
Haakon B
HB
Benestad
Truls
T
Raastad
D000222:Adaptation, Physiological; D000328:Adult; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D010101:Oxygen Consumption / Q000187:drug effects*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010807:Physical Endurance / Q000187:drug effects*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014810:Vitamin E / Q000008:administration & dosage / Q000494:pharmacology*; D014815:Vitamins / Q000008:administration & dosage / Q000494:pharmacology*; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism
C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D014157:Transcription Factors; D014815:Vitamins; D014810:Vitamin E; C539675:COX4I2 protein, human; D003576:Electron Transport Complex IV; D019950:Mitogen-Activated Protein Kinase 1; D020764:cdc42 GTP-Binding Protein; D001205:Ascorbic Acid