Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, United States.
Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso.
J Nutr. 2023 Apr;153(4):949-957. doi: 10.1016/j.tjnut.2023.02.002. Epub 2023 Feb 6.
Stable isotope techniques using C to assess vitamin A (VA) dietary sources, absorption, and total body VA stores (TBSs) require determination of baseline C abundance. C-natural abundance is approximately 1.1% total carbon, but varies with foods consumed, supplements taken, and food fortification with synthetic retinyl palmitate.
We determined C variation from purified serum retinol and the resulting impact on TBSs using pooled data from preschool children in Burkina Faso, Cameroon, Ethiopia, South Africa, Tanzania, and Zambia and Zambian women.
Seven studies included children (n = 639; 56 ± 25 mo; 48% female) and one in women (n = 138; 29 ± 8.5 y). Serum retinol C-natural abundance was determined using GC-C-IRMS. TBSs were available in 7 studies that employed retinol isotope dilution (RID). Serum CRP and α-acid-glycoprotein (AGP) were available from 6 studies in children. Multivariate mixed models assessed the impact of covariates on retinol C. Spearman correlations and Bland-Altman analysis compared serum and milk retinol C and evaluated the impact of using study- or global-retinol C estimates on calculated TBSs.
C-natural abundance (%, median [Q1, Q3]) differed among countries (low: Zambia, 1.0744 [1.0736, 1.0753]; high: South Africa, 1.0773 [1.0769, 1.0779]) and was associated with TBSs, CRP, and AGP in children and with TBSs in women. C-enrichment from serum and milk retinol were correlated (r = 0.52; P = 0.0001). RID in children and women using study and global estimates had low mean bias (range, -3.7% to 2.2%), but larger 95% limits of agreement (range, -23% to 37%).
C-natural abundance is different among human cohorts in Africa. Collecting this information in subgroups is recommended for surveys using RID. When TBSs are needed on individuals in clinical applications, baseline C measures are important and should be measured in all enrolled subjects.
使用 C 稳定同位素技术来评估维生素 A（VA）的饮食来源、吸收和全身 VA 储存量（TBS），需要确定基线 C 丰度。C 的自然丰度约为总碳的 1.1%，但会因所食用的食物、服用的补充剂以及用合成视黄醇棕榈酸酯进行的食物强化而有所不同。
我们使用来自布基纳法索、喀麦隆、埃塞俄比亚、南非、坦桑尼亚和赞比亚的学龄前儿童以及赞比亚妇女的汇总数据，确定了从纯化血清视黄醇中得出的 C 变化及其对 TBS 的影响。
有 7 项研究纳入了儿童（n = 639；56 ± 25 个月；48%为女性），1 项研究纳入了妇女（n = 138；29 ± 8.5 岁）。使用 GC-C-IRMS 测定血清视黄醇的 C 自然丰度。有 7 项研究采用视黄醇同位素稀释（RID）法获得了 TBS。有 6 项儿童研究提供了血清 C 反应蛋白（CRP）和α-酸性糖蛋白（AGP）的数据。多变量混合模型评估了协变量对视黄醇 C 的影响。Spearman 相关性和 Bland-Altman 分析比较了血清和牛奶视黄醇 C，并评估了使用研究或全球视黄醇 C 估计值对计算出的 TBS 的影响。
各国之间的 C 自然丰度（%，中位数[Q1、Q3]）存在差异（低值：赞比亚，1.0744 [1.0736、1.0753]；高值：南非，1.0773 [1.0769、1.0779]），且与儿童的 TBS、CRP 和 AGP 以及妇女的 TBS 有关。血清和牛奶视黄醇的 C 富集呈相关性（r = 0.52；P = 0.0001）。使用研究和全球估计值的儿童和妇女 RID 的平均偏差较小（范围，-3.7%至 2.2%），但 95%一致性界限较大（范围，-23%至 37%）。
非洲不同人群的 C 自然丰度存在差异。在使用 RID 进行调查时，建议在亚组中收集这些信息。在临床应用中需要对个体的 TBS 进行评估时，基线 C 测量很重要，并且应在所有入组受试者中进行测量。
