β-carotene-vitamin A equivalence in Chinese adults assessed by an isotope dilution technique
β-carotene-vitamin A equivalence in Chinese adults assessed by an isotope dilution technique
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DOI：
10.1079/bjn20031030
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发表时间：
2004-01-01
影响因子：
3.6
通讯作者：
Tang, GW
中科院分区：
文献类型：
--
作者：
Wang, ZX;Yin, S;Tang, GW
本文用稳定同位素稀释法测定了中国成年人合成H-2标记的β-胡萝卜素到维生素A的转换系数。15名50~60岁的健康志愿者参加了55d的实验。受试者(男9人，女6人)在实验的第一天给予生理剂量的[H-2(8)]β-胡萝卜素(6 Mg)，在第四天给予参考剂量的[H-2(8)]视黄酸乙酯(3 Mg)。在研究的第一天和第四天分别在0、3、5、7、9、11和13h采集血清样本，连续10d，然后从第14天到56d每周采集一次血清样本。从血清中提取β-胡萝卜素和视黄醇，用气相色谱-电子捕获负化学电离-质谱仪和LC-大气压化学电离-质谱仪分别测定其含量。其中四名受试者的β-胡萝卜素转化为维生素A的摩尔系数为29.0：1，被称为“糟糕的转化率”。在11名正常转化者(7名男性和4名女性)中，计算出的β-胡萝卜素到视黄醇的转换系数范围为2.0：1至12.2：1，平均摩尔数为4.8(SD 2.8)：1，按重量计算为3.8：1至22.8：1，平均为9.1(SD 5.3)：1。52d后的肠道吸收转化率约为总转化率的30%。
The present study was carried out to determine the conversion factor of synthetic H-2-labelled beta-carotene to vitamin A in Chinese adults by using a stable-isotope dilution technique. Fifteen healthy volunteers aged 50-60 years were recruited for a 55 d experiment. The volunteers (nine males and six females) were each given a physiological dose Of [H-2(8)] beta-carotene (6 mg) in oil on the first day of the experiment, and a reference dose of [H-2(8)]retinyl acetate (3 mg) in oil was given on the fourth day. Serum samples were collected at 0, 3, 5, 7, 9, 11, and 13 h on the first and the fourth days of the study, daily for 10 d, and then weekly from days 14 to 56. beta-Carotene and retinol were extracted from serum and isolated by HPLC, and their enrichments were respectively determined by using GC-electron capture negative chemical ionisation-MS and LC-atmospheric pressure chemical ionisation interface-MS. Four of the subjects exhibited beta-carotene to vitamin A conversion factors of > 29.0: 1 on a molar basis and were termed 'poor converters'. In the eleven normal converters (seven males and four females), the calculated conversion factors of beta-carotene to retinol ranged from 2.0:1 to 12.2:1 with an average of 4.8 (SD 2.8):1 on a molar basis, and from 3.8:1 to 22.8:1 with an average of 9.1 (SD 5.3):1 on a weight basis. The 52d post-intestinal absorption conversion was estimated to be about 30 % of the-total converted retinol.