Laboratory of Toxicology, Faculty of Health Science, University of Brasilia, Campus Darcy Ribeiro, Brasilia, Brazil.
Biol Trace Elem Res. 2013 Jan;151(1):30-7. doi: 10.1007/s12011-012-9542-2. Epub 2012 Nov 15.
Breast milk samples collected from 18 nursing mothers between the 15th and 90th day of lactation were digested in nitric acid in a microwave, and total mercury (THg) levels were quantified by atomic fluorescence spectrometry. Participants responded to a 24-h dietary recall questionnaire on the 74th and 76th day of lactation and to a Food Frequency Questionnaire querying the frequency of fish intake over the last 90 days. Usual intake was estimated using the PC-SIDE software package. A meal of fish was offered on the 75th day of lactation. Mothers' individual mean THg levels ranged from <0.76 to 22.7 ng/mL during the period, and the mean level for all samples (n = 142) was 6.47 ±6.04 ng/mL. The multilevel mixed linear model used showed high heterogeneity of the mercury levels among the mothers, and THg levels did not change significantly over the period under study. However, a significant increase in THg levels was observed after the intervention with the fish meal. Exposure increased for most infants on the 90th day of lactation, with intakes exceeding the THg provisional tolerable weekly intake (PTWI) at least once during the period for 77.8 % of samples. Mothers consumed mostly food from the fat and grain groups, and a significant correlation was detected between consumption of food of these groups and breast milk THg levels (p = 0.006 and 0.007). A significant correlation was also found between vegetable consumption and carbohydrate intake and THg levels in the samples (p = 0.015 and 0.045, respectively). No correlation was found between mothers' daily fish consumption frequency and THg levels. Although this study showed that mercury intake by infants during lactation may exceed the toxicologically safe exposure level (PTWI), we nevertheless believe that the benefits of lactation for both the mother and the infant outweigh the eventual risks that this exposure may represent.
从 18 位哺乳期母亲的第 15 天到第 90 天收集的母乳样本在微波中用硝酸消化，然后通过原子荧光光谱法定量总汞（THg）水平。参与者在哺乳期第 74 天和第 76 天分别回答了 24 小时膳食回忆问卷和过去 90 天内鱼类摄入频率的食物频率问卷。使用 PC-SIDE 软件包估算了通常的摄入量。在哺乳期第 75 天提供了一顿鱼餐。在此期间，母亲个体的平均 THg 水平范围从<0.76 至 22.7ng/mL，所有样本（n=142）的平均水平为 6.47±6.04ng/mL。使用的多级混合线性模型显示，母亲之间的汞水平存在高度异质性，并且在研究期间，THg 水平没有明显变化。然而，在干预鱼餐后，THg 水平明显增加。在哺乳期第 90 天，大多数婴儿的暴露量增加，在此期间，至少有 77.8%的样本的摄入量超过了 THg 暂定可耐受每周摄入量（PTWI）。母亲主要食用脂肪和谷物组的食物，并且在这些组的食物消耗与母乳 THg 水平之间检测到显著相关性（p=0.006 和 0.007）。还发现蔬菜消耗与样本中的碳水化合物摄入量与 THg 水平之间存在显著相关性（p=0.015 和 0.045）。母亲每日鱼类消费频率与 THg 水平之间没有相关性。尽管这项研究表明，哺乳期婴儿的汞摄入量可能超过毒理学安全暴露水平（PTWI），但我们仍然认为母乳喂养对母亲和婴儿的益处超过了这种暴露可能带来的最终风险。
