Oxidative stress in humans training in a cold, moderate altitude environment and their response to a phytochemical antioxidant supplement

Objective.-This study examined the effectiveness of an antioxidant mixture containing vitamin E, P-carotene, ascorbic acid, selenium, a-lipoic acid, N-acetyl 1-cysteine, catechin, lutein, and lycopene to reduce oxidative stress in US Marines undergoing 24 days of cold-weather field training at a moderate altitude. Methods.-Forty physically active male volunteers (ages 18-40) were randomly assigned to a treatment (antioxidant) group (n = 21) or a control (placebo) group (n = 19). Breath pentane (BP), serum lipid hydroperoxides (LPO), urine malondialdehyde (MDA), urine 8-hydroxy deoxyguanosine (8-OHdG), ferric-reducing ability of plasma (FRAP), and serum and urine oxygen radical absorption capacity (ORAC) were measured as indicators of oxidative stress and antioxidant status. Urine was sampled at days 0, 12, and 24. Serum and breath were sampled on days 0 and 24. Results.-Both groups exhibited increased levels of oxidative stress after 24 days of field training, as indicated by an increased LPO, pentane, and 8-OHdG. There was no significant difference between the treatment and placebo groups at day 24; however, there was some indication that test subjects with initially low antioxidant capacity (ORAC) may have benefited from the antioxidant supplement. Conclusions.-An increased level of oxidative stress was associated with high levels of physical exertion of training in a cold environment at moderate altitude. The antioxidant mixture tested did not attenuate the mean oxidative stress levels in the entire group of test subjects, but it may have reduced the oxidative stress of some individuals with low initial antioxidant status.