Oral antioxidant supplementation does not prevent acute mountain sickness: double blind, randomized placebo-controlled trial.
What this study found
Oral antioxidant supplementation did not prevent acute mountain sickness or improve related physiologic measures at 5200 m. On Day 2, acute mountain sickness by Lake Louise Consensus symptom score > 3 occurred in 25/36 (69%) antioxidant participants versus 23/35 (66%) placebo participants (P = 0.74). There were no differences in AMS severity by VAS, pulmonary artery pressure, or oxygen saturation. The authors concluded that this antioxidant combination is not effective for AMS prophylaxis.
- Study & population
- Double-blind, randomized, placebo-controlled trial in healthy lowland volunteers enrolled in the Apex 2 expedition to Bolivia.
- Intervention
- The active regimen was a daily oral antioxidant combination in sealed capsules: 1 g L-ascorbic acid, 400 IU a-tocopherol acetate, and 600 mg alpha-lipoic acid, taken in four divided doses per day.
- Key limitation
- The primary outcome was available for only 36 of 41 participants in the antioxidant arm.
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Open PDFOriginal abstract
BACKGROUND Acute mountain sickness may be caused by cerebrovascular fluid leakage due to oxidative damage to the endothelium. This may be reduced by oral antioxidant supplementation. AIM To assess the effectiveness of antioxidant supplementation for the prevention of acute mountain sickness (AMS). DESIGN A parallel-group double blind, randomized placebo-controlled trial. METHODS The study was conducted in a university clinical research facility and a high altitude research laboratory. Eighty-three healthy lowland volunteers ascended to 5200 m on the Apex 2 high altitude research expedition. The treatment group received a daily dose of 1 g l-ascorbic acid, 400 IU of alpha-tocopherol acetate and 600 mg of alpha-lipoic acid (Cultech Ltd., Wales, UK) in four divided doses. Prevalence of AMS was measured using the Lake Louise Consensus score sheet (LLS). Secondary outcomes were AMS severity measured using a novel visual analogue scale, arterial oxygen saturation and pulmonary artery systolic pressure (PASP). RESULTS Forty-one subjects were allocated to the antioxidant group, and 42 to the placebo group. There was no difference in AMS incidence or severity between the antioxidant and placebo groups using the LLS at any time at high altitude. At the pre-determined comparison point at Day 2 at 5200 m, 69% of the antioxidant group (25/36) and 66% of the placebo group (23/35) had AMS using the LLS criteria (P = 0.74). No differences were observed between the groups for PASP, oxygen saturation, presence of a pericardial effusion or AMS assessed by VAS. CONCLUSION This trial found no evidence of benefit from antioxidant supplementation at high altitude. TRIAL REGISTRATION NUMBER NCT00664001.