Venn Bernard J, Green Timothy J, Moser Rudolf, McKenzie Joanne E, Skeaff C Murray, Mann Jim
Department of Human Nutrition and. Preventive and Social Medicine University of Otago, Dunedin, New Zealand.
J Nutr. 2002 Nov;132(11):3353-5. doi: 10.1093/jn/132.11.3353.
The natural diastereoisomer [6S]-5-methyltetrahydrofolate ([6S]-5-MTHF) may be a safer fortificant than folic acid for neural tube defect (NTD) prevention because it is unlikely to mask vitamin B-12 deficiency. An inverse relationship between NTD risk and blood folate concentrations has been reported. In this randomized, placebo-controlled, double-blind trial, we compared the effects of [6S]-5-MTHF and folic acid supplementation for 24 wk on plasma folate and red cell folate (RCF) in women of childbearing age (18-49 y). Women (n = 104) were randomly assigned to receive a supplement containing [6S]-5-MTHF (113 micro g/d), folic acid (100 micro g/d) or placebo. The mean estimated linear increase in plasma folate concentration was 0.3 [95% confidence interval (CI): 0.1, 0.5], and 0.4 (0.2, 0.6) nmol/(L. wk) in the [6S]-5-MTHF and folic acid groups, respectively. The mean estimated linear increase in RCF was 7.4 (95% CI: 4.5, 10.3), and 8.3 (4.4, 12.3) nmol/(L. wk) in the [6S]-5-MTHF and folic acid groups, respectively. There were no differences in the slopes between the [6S]-5-MTHF group and the folic acid group in either plasma folate (P = 0.48) or RCF (P = 0.70). At 24 wk, estimated mean increases in plasma folate concentrations were 6.9 (95% CI: 1.7, 12.2) and 9.2 (3.3, 15.1) nmol/L, and in RCF, 251 (143, 360) and 275 (148, 402) nmol/L, in the [6S]-5-MTHF and folic acid groups, respectively, relative to the placebo group. These data suggest that low dose [6S]-5-MTHF and folic acid supplementation increase blood folate indices to a similar extent. A steady state in the blood indices had not been reached by 24 wk.
天然非对映异构体[6S]-5-甲基四氢叶酸（[6S]-5-MTHF）对于预防神经管缺陷（NTD）可能是一种比叶酸更安全的强化剂，因为它不太可能掩盖维生素B-12缺乏症。已有报道称NTD风险与血液叶酸浓度之间呈负相关。在这项随机、安慰剂对照、双盲试验中，我们比较了补充[6S]-5-MTHF和叶酸24周对育龄妇女（18 - 49岁）血浆叶酸和红细胞叶酸（RCF）的影响。104名女性被随机分配接受含有[6S]-5-MTHF（113微克/天）、叶酸（100微克/天）或安慰剂的补充剂。[6S]-5-MTHF组和叶酸组血浆叶酸浓度的平均估计线性增加分别为0.3[95%置信区间（CI）：0.1，0.5]和0.4（0.2，0.6）纳摩尔/（升·周）。RCF的平均估计线性增加在[6S]-5-MTHF组和叶酸组中分别为7.4（95%CI：4.5，10.3）和8.3（4.4，12.3）纳摩尔/（升·周）。[6S]-5-MTHF组和叶酸组在血浆叶酸（P = 0.48）或RCF（P = 0.70）方面的斜率没有差异。在24周时，相对于安慰剂组，[6S]-5-MTHF组和叶酸组血浆叶酸浓度的估计平均增加分别为6.9（95%CI：1.7，12.2）和9.2（3.3，15.1）纳摩尔/升，RCF分别为251（143，360）和275（148，402）纳摩尔/升。这些数据表明，低剂量补充[6S]-5-MTHF和叶酸可使血液叶酸指标升高到相似程度。到24周时血液指标尚未达到稳态。
