JP van Wijngaarden, Wageningen University, Division of Human Nutrition, P.O. Box 8129, 6700 EV Wageningen, The Netherlands. Email:
J Nutr Health Aging. 2017;21(10):1268-1276. doi: 10.1007/s12603-017-0911-6.
Vitamin B12 status is measured by four plasma/ serum biomarkers: total vitamin B12 (total B12), holotranscobalamin (holoTC), methylmalonic acid (MMA) and homocysteine (tHcy). Associations of B12 intake with holoTC and tHcy and associations between all four biomarkers have not been extensively studied. A better insight in these associations may contribute to an improved differentiation between vitamin B12 deficiency and a normal vitamin B12 status.
This study investigates associations between vitamin B12 intake and biomarkers and associations between biomarkers.
In this cross-sectional observational study, levels of total B12, HoloTC, MMA and tHcy were determined in participants of the B-PROOF study: 2919 elderly people (≥65 years, with a mean age of 74.1 years, a mean BMI of 27.1 and 50% women) with elevated tHcy levels (≥12 µmol/L). B12 intake was assessed in a subsample. We assessed the association between intake and status with multivariate regression analysis. We explored the dose-response association between B12 intake and biomarkers and the association of total B12 and holoTC with tHcy and MMA with restricted cubic spline plots.
A doubling of B12 intake was associated with 9% higher total B12, 15% higher HoloTC, 9% lower MMA and 2% lower tHcy. Saturation of biomarkers occurs with dietary intakes of >5 μg B12. Spline regression showed that levels of MMA and tHcy started to rise when vitamin B12 levels fall below 330 pmol/L and with HoloTC levels below 100 pmol/L, with a sharp increase with levels of B12 and HoloTC below 220 and 50 pmol/L respectively.
In this study we observed a significant association between vitamin B12 intake and vitamin B12 biomarkers and between the biomarkers. The observed inflections for total B12 and holoTC with MMA and tHcy could indicate cut-off levels for further testing for B12 deficiency and determining subclinical B12 deficiency.
维生素 B12 状况通过四种血浆/血清生物标志物来衡量：总维生素 B12（总 B12）、全钴胺素（holoTC）、甲基丙二酸（MMA）和同型半胱氨酸（tHcy）。B12 摄入量与 holoTC 和 tHcy 的关系以及这四种生物标志物之间的关系尚未得到广泛研究。更好地了解这些关系可能有助于更好地区分维生素 B12 缺乏症和正常的维生素 B12 状态。
本研究调查了 B12 摄入量与生物标志物之间的关系以及生物标志物之间的关系。
在这项横断面观察性研究中，对 B-PROOF 研究中的参与者进行了总 B12、HoloTC、MMA 和 tHcy 水平的测定：2919 名老年人（≥65 岁，平均年龄 74.1 岁，平均 BMI 为 27.1，女性占 50%），其 tHcy 水平升高（≥12 μmol/L）。在一个子样本中评估了 B12 的摄入量。我们使用多元回归分析评估了摄入量和状态之间的关系。我们通过限制性立方样条图探索了 B12 摄入量与生物标志物之间的剂量-反应关系以及总 B12 和 holoTC 与 tHcy 和 MMA 与 tHcy 的关系。
B12 摄入量增加一倍与总 B12 增加 9%、HoloTC 增加 15%、MMA 降低 9%和 tHcy 降低 2%有关。当膳食摄入量>5μg B12 时，生物标志物达到饱和。样条回归显示，当维生素 B12 水平降至 330 pmol/L 以下时，MMA 和 tHcy 水平开始升高，当 HoloTC 水平降至 100 pmol/L 以下时，MMA 和 tHcy 水平急剧升高，分别在 B12 和 HoloTC 水平低于 220 和 50 pmol/L 时达到高峰。
在这项研究中，我们观察到 B12 摄入量与 B12 生物标志物之间以及生物标志物之间存在显著关联。总 B12 和 holoTC 与 MMA 和 tHcy 的拐点可能表明需要进一步测试 B12 缺乏症并确定亚临床 B12 缺乏症的临界值。
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