Vitamin E supplementation protects erythrocyte membranes from oxidative stress in healthy Chinese middle-aged and elderly people

Abstract

Elderly people are subject to higher levels of oxidative stress than are young people. Vitamin E, as a powerful antioxidant residing mainly in biomembranes, may provide effective protection against oxidative membrane damage and resultant age-related deterioration, especially in the elderly. We hypothesized that appropriate levels of vitamin E supplementation would protect erythrocyte membranes from oxidative stress and thus improve membrane fluidity in healthy middle-aged and elderly people. To test this, we conducted a 4-month double-blind, randomized trial in which 180 healthy subjects (55-70 years old) were randomly divided into 4 groups: group C (control), and 3 treatment groups in which daily doses of 100 mg (VE1), 200 mg (VE2), and 300 mg (VE3) dl-α-tocopheryl acetate were administered. We measured plasma α-tocopherol concentration, malondialdehyde, and superoxide dismutase levels, erythrocyte hemolysis, and erythrocyte membrane fluidity at the beginning and end of the trial. After 4 months supplementation, plasma α-tocopherol concentrations in the 3 treatment groups had increased by 71%, 78%, and 95%, respectively (all P < .01), and significant decreases in plasma malondialdehyde concentrations were observed in these groups (all P < .05). Erythrocyte hemolysis was decreased by 20% to 38% after vitamin E supplementation (all P < .05), and in addition, groups VE2 and VE3 showed dramatic improvements in erythrocyte membrane fluidity (P < .01). Surprisingly, superoxide dismutase activity also decreased significantly in the treatment groups (all P < .05). In summary, vitamin E supplementation apparently alleviates oxidative stress in healthy middle-aged to elderly people, at least in part by improving erythrocyte membrane fluidity and reducing erythrocyte hemolysis.