1.
Vitamin E supplementation protects erythrocyte membranes from oxidative stress in healthy Chinese middle-aged and elderly people.
Sun, Y, Ma, A, Li, Y, Han, X, Wang, Q, Liang, H
Nutrition research (New York, N.Y.). 2012;(5):328-34
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.
2.
Effects of vitamin E on plasma lipid status and oxidative stress in Chinese women with metabolic syndrome.
Wang, Q, Sun, Y, Ma, A, Li, Y, Han, X, Liang, H
International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition. 2010;(3):178-87
Abstract
Following the change of dietary structure and living style, metabolic syndrome (MetS) has become increasingly common in China, especially in women, who have abnormal plasma lipid profiles with increased levels of oxidative stress. Vitamin E (VitE) is a powerful chain-breaking antioxidant, which may be a protective factor against oxidative stress-related diseases. This study investigated the effects of three different dosages of tocopherol supplementation (100 IU /day, 200 IU /day, 300 IU /day) for 4 months in Chinese women with MetS. The plasma VitE concentrations increased significantly after the 4 months of supplementation (p < 0.01). The protective decreases in plasma total cholesterol were significant in 200 IU/day and 300 IU/day VitE groups (p < 0.05), but decreases in high-density lipoprotein cholesterol were also significant in all the supplementation groups (p < 0.05). Plasma triglycerides were unaltered (p > 0.05). The indicators of oxidative stress decreased substantially in all of the VitE supplementation groups: malondialdehyde (MDA) was reduced by nearly 50 percent (all groups, p < 0.001), erythrocyte hemolysis was decreased by nearly 40 percent (all groups, p < 0.05); among which the 300IU/day VitE group showed the most significant effect. However, the activity of superoxide dismutase (SOD) decreased after the trial (p < 0.001). VitE provided marked benefits in reducing oxidative stress levels and improving lipid status in women with MetS. Although no dose-effect relationship was observed, 300 IU VitE per day showed the optimal effect. Research is needed to identify potential protective mechanisms or utilization of vitamin E during MetS.