Burton G W, Traber M G, Acuff R V, Walters D N, Kayden H, Hughes L, Ingold K U
Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario.
Am J Clin Nutr. 1998 Apr;67(4):669-84. doi: 10.1093/ajcn/67.4.669.
We report a comparison of natural and synthetic vitamin E in humans using deuterium labeling to permit the two forms of vitamin E to be measured independently in plasma and tissues of each subject. Differences in natural and synthetic vitamin E concentrations were measured directly under equal dosage conditions using an equimolar mixture of deuterated RRR-alpha-tocopheryl acetate and all-rac-alpha-tocopheryl acetate. Two groups of five adults took 30 mg of the mixture as a single dose and as eight consecutive daily doses, respectively. After a 1-mo interval the schedule was repeated but with a 10-fold higher dose (ie, 300 mg). In each case, the ratio of plasma d3-RRR-alpha-tocopherol to d6-all-rac-alpha-tocopherol (RRR:rac) increased from approximately 1.5-1.8 to approximately 2 after dosing ended. In an elective surgery study in which 22 patients were given 150 mg/d for up to 41 d before surgery, the RRR:rac in tissues was lower than in plasma and the percentage of deuterated alpha-tocopherol was lower in all tissues except gallbladder and liver. In a terminally ill patient given 30 mg/d for 361 d, plasma and tissue (x+/-SD) RRR-rac ratios (and % deuterated alpha-tocopherol) at autopsy were 2.06 (6.3%) and 1.71+/-0.24 (5.9+/-2.2%), respectively. In a second terminally ill patient given 300 mg/d for 615 d, the corresponding values were 2.11 (68%) and 2.01+/-0.17 (65+/-10%), respectively. The results indicated that natural vitamin E has roughly twice the availability of synthetic vitamin E. This 2:1 ratio is significantly higher than the currently accepted RRR:rac of 1.36:1.00. Gamma-Tocopherol, expressed as a fraction of total unlabeled tocopherols in 15 elective surgery patients, was 1.4-4.6 (mean: 2.6) times greater in adipose tissue, muscle, skin, and vein than in plasma, which is a substantially larger fraction than had been recognized previously.
我们报告了一项针对人类的天然维生素E与合成维生素E的比较研究，该研究使用氘标记法，以便在每个受试者的血浆和组织中独立测量这两种形式的维生素E。在等剂量条件下，使用氘代RRR-α-生育酚醋酸酯和消旋-α-生育酚醋酸酯的等摩尔混合物直接测量天然和合成维生素E浓度的差异。两组各五名成年人分别单次服用30毫克该混合物以及连续八天每日服用30毫克。在间隔1个月后重复该给药方案，但剂量提高10倍（即300毫克）。在每种情况下，给药结束后血浆中d3-RRR-α-生育酚与d6-消旋-α-生育酚的比例（RRR:rac）从约1.5 - 1.8增加到约2。在一项择期手术研究中，22名患者在手术前长达41天的时间里每天服用150毫克，组织中的RRR:rac低于血浆中的比例，并且除胆囊和肝脏外，所有组织中氘代α-生育酚的百分比均较低。在一名终末期患者中，其连续361天每天服用30毫克，尸检时血浆和组织（x±SD）的RRR-rac比例（以及氘代α-生育酚的百分比）分别为2.06（6.3%）和1.71±0.24（5.9±2.2%）。在另一名终末期患者中，其连续615天每天服用300毫克，相应的值分别为2.11（68%）和2.01±0.17（65±10%）。结果表明，天然维生素E的利用率约为合成维生素E的两倍。这个2:1的比例显著高于目前公认的RRR:rac的1.36:1.00。在15名择期手术患者中，以γ-生育酚占未标记总生育酚的比例表示，其在脂肪组织、肌肉、皮肤和静脉中的含量比血浆中高1.4 - 4.6倍（平均为2.6倍），这一比例比之前认识到的要大得多。
