Elmadfa I, Park E
Institute of Nutritional Science, University of Vienna, Austria.
Eur J Nutr. 1999 Dec;38(6):286-92. doi: 10.1007/s003940050079.
Plant fats and oils are major sources of mono- and polyunsaturated fatty acids as well as vitamin E, the major fat-soluble antioxidants in human nutrition. Dietary antioxidants are expected to reduce cancer risk by minimizing DNA damage.
To compare the effects of gamma-tocopherol rich corn oil and the mixture of the alpha-tocopherol rich olive/sunflower oil on plasma concentration of tocopherols and on the frequency of sister chromatid exchange (SCE), an indicator of DNA damage.
This study had a double-blind, cross-over design and was conducted in 20 normal healthy non-smoking males aged 19-31 years. Design included a 2-week adjustment period and two 2-week test periods in which diets containing 30% energy as fat including either 80 g of corn oil (CO) (20 mg alpha-tocopherol, 100 mg gamma-tocopherol) or 80 g of olive/ sunflower oil (OSO) (24 mg alpha-tocopherol, 2.4 mg gamma-tocopherol), as the main fat-source, were given. Blood samples for analysis of SCE rate and content of tocopherols were collected at the beginning (T0), after adjustment (T1) and after the test period (T2) in intervals of 2 weeks.
After two weeks of the corn oil diet, the plasma concentration of gamma-tocopherol increased but alpha-tocopherol decreased significantly compared to the olive/sunflower oil diet. The concentration of alpha-tocopherol increased (CO: 22.99 +/- 1.11 vs. OSO: 24.40 +/- 1.49 micromol/l) and that of gamma-tocopherol decreased (CO: 4.19 +/- 0.29 vs. OSO: 2.99 +/- 0.25 micromol/l) after the olive/sunflower oil diet. Intake of the corn oil diet was associated with reduced SCE rate and intensity, whereas there was no change in SCE after the olive/sunflower oil diet (CO: 7.66 +/- 0.25 vs. OSO: 8.06 +/- 0.47 mean SCE/cell)
The combination of gamma-tocopherol with alpha-tocopherol in corn oil diet despite the lower alpha-tocopherol equivalents/diene acid equivalents ratio achieved better protection against DNA damage than alpha-tocopherol alone in the olive/sunflower oil diet.
植物油脂是单不饱和脂肪酸和多不饱和脂肪酸以及维生素E的主要来源，维生素E是人类营养中主要的脂溶性抗氧化剂。膳食抗氧化剂有望通过减少DNA损伤来降低癌症风险。
比较富含γ-生育酚的玉米油与富含α-生育酚的橄榄油/葵花籽油混合物对生育酚血浆浓度以及对姐妹染色单体交换（SCE）频率（DNA损伤指标）的影响。
本研究采用双盲交叉设计，对20名年龄在19 - 31岁的正常健康不吸烟男性进行。设计包括2周的调整期和两个2周的测试期，测试期内给予含30%能量为脂肪的饮食，其中一种饮食以80克玉米油（CO）（20毫克α-生育酚，100毫克γ-生育酚）作为主要脂肪来源，另一种饮食以80克橄榄油/葵花籽油（OSO）（24毫克α-生育酚，2.4毫克γ-生育酚）作为主要脂肪来源。在开始时（T0）、调整后（T1）和测试期后（T2），每隔2周采集血样用于分析SCE率和生育酚含量。
与橄榄油/葵花籽油饮食相比，食用玉米油饮食两周后，血浆γ-生育酚浓度升高，但α-生育酚浓度显著降低。食用橄榄油/葵花籽油饮食后，α-生育酚浓度升高（CO：22.99±1.11对OSO：24.40±1.49微摩尔/升），γ-生育酚浓度降低（CO：4.19±0.29对OSO：2.99±0.25微摩尔/升）。食用玉米油饮食与SCE率和强度降低相关，而食用橄榄油/葵花籽油饮食后SCE无变化（CO：7.66±0.25对OSO：8.06±0.47平均SCE/细胞）
尽管玉米油饮食中α-生育酚当量/二烯酸当量比值较低，但γ-生育酚与α-生育酚的组合比橄榄油/葵花籽油饮食中单独的α-生育酚对DNA损伤具有更好的保护作用。
