Fanti Paolo, Stephenson Tammy J, Kaariainen Ismo M, Rezkalla Butros, Tsukamoto Yusuke, Morishita Tetsuo, Nomura Masanori, Kitiyakara Chagriya, Custer Laurie J, Franke Adrian A
University of Kentucky Medical Center, Lexington, KY 40536, USA.
Nephrol Dial Transplant. 2003 Sep;18(9):1862-8. doi: 10.1093/ndt/gfg229.
Soya foods, a staple in several Asian countries, have received increasing attention because of their nutritional properties and their high isoflavone content. We have shown recently abnormal pharmacokinetics of soya isoflavones following acute oral intake, in soya-naive end-stage renal disease (ESRD) patients. No information is available, however, about blood levels of soya isoflavones in ESRD patients with habitual soya intake. Additionally, no information is available about the conjugation profile of these compounds in ESRD patients.
To assess the relationship between habitual soya intake on blood isoflavone levels in ESRD patients, we recorded dietary soya food intake and analysed circulating levels of soya isoflavones in randomly selected, clinically stable haemodialysis patients from the United States (n = 20), Thailand (n = 17) and Japan (n = 20). Dietary records and three weekly blood samples were collected from each participant. Combined isoflavones and individual genistein, daidzein, glycitein and O-desmethylangolensin (DMA) were analysed in serum by liquid chromatography/mass spectrometry. Lipid phase micronutrients, including tocopherols, carotenoids and retinol were also measured to compare ethnic differences in isoflavones with those of more common lipid soluble antioxidant micronutrients.
Soya intake was higher in Japanese than in Thai patients and it was negligible in the US patients. Blood levels of genistein were very elevated and significantly higher in the Japanese patients (1128 +/- 205 nM), as compared with the Thai and US patients (258 +/- 64 and 168 +/- 49 nM, respectively; P < 0.001). The other isoflavones followed the same trend. Daidzein was more concentrated than genistein in the dialysis patients. Robust correlation was present between weekly soya intake and blood isoflavone levels (r = 0.56, P < 0.001). Despite very high total isoflavone concentrations, the levels of unconjugated and sulphated isoflavones in the Japanese patients were comparable to those described in healthy subjects. Compared with the striking difference in isoflavones, more easily accessible dietary antioxidants, including tocopherols, carotenoids and retinol, differed only minimally or not at all in the three groups.
ESRD patients appear to accumulate isoflavones as a function of dietary soya intake, resulting in blood concentrations that are higher than those reported in subjects with preserved kidney function. Even in the presence of very elevated total isoflavone levels, the concentrations of the unconjugated and sulphated fractions are comparable to those of healthy subjects. A discrepancy is noted between accumulation of soya isoflavones and other more common lipid-soluble antioxidant micronutrients.
大豆食品是几个亚洲国家的主食，因其营养特性和高异黄酮含量而受到越来越多的关注。我们最近发现，在未食用过大豆的终末期肾病（ESRD）患者中，急性口服大豆异黄酮后存在异常的药代动力学。然而，关于长期食用大豆的ESRD患者血液中大豆异黄酮水平的信息却尚无报道。此外，关于这些化合物在ESRD患者中的结合情况也没有相关信息。
为了评估长期食用大豆与ESRD患者血液中异黄酮水平之间的关系，我们记录了大豆食品的饮食摄入量，并分析了从美国（n = 20）、泰国（n = 17）和日本（n = 20）随机选取的临床稳定的血液透析患者循环中大豆异黄酮的水平。从每位参与者处收集饮食记录和每周三次的血液样本。通过液相色谱/质谱法分析血清中总异黄酮以及单个染料木黄酮、大豆苷元、黄豆黄素和O - 去甲基安哥拉紫檀素（DMA）的含量。还测量了脂质相中的微量营养素，包括生育酚、类胡萝卜素和视黄醇，以比较异黄酮与更常见的脂溶性抗氧化微量营养素在种族上的差异。
日本患者的大豆摄入量高于泰国患者，而美国患者的大豆摄入量可忽略不计。与泰国和美国患者（分别为258±(64) nM和168±(49) nM；P < 0.001）相比，日本患者血液中的染料木黄酮水平非常高且显著更高（1128±(205) nM）。其他异黄酮也呈现相同趋势。在透析患者中，大豆苷元比染料木黄酮更浓缩。每周大豆摄入量与血液异黄酮水平之间存在显著相关性（r = 0.56，P < 0.001）。尽管总异黄酮浓度非常高，但日本患者中未结合和硫酸化异黄酮的水平与健康受试者中描述的水平相当。与异黄酮的显著差异相比，三组中更容易获取的饮食抗氧化剂，包括生育酚、类胡萝卜素和视黄醇，差异极小或根本没有差异。
ESRD患者似乎会根据大豆的饮食摄入量积累异黄酮，导致血液浓度高于肾功能正常受试者的报告水平。即使总异黄酮水平非常高，未结合和硫酸化部分的浓度也与健康受试者相当。大豆异黄酮的积累与其他更常见的脂溶性抗氧化微量营养素之间存在差异。
