Jackson Kristina Harris, Polreis Jason, Sanborn Laura, Chaima David, Harris William S
OmegaQuant Analytics LLC, Sioux Falls, SD USA.
Department of Microbiology, University of Malawi, College of Medicine, Blantyre, Malawi.
Int Breastfeed J. 2016 Jan 25;11:1. doi: 10.1186/s13006-016-0060-2. eCollection 2016.
The effect of breast milk fatty acid (FA) composition, particularly levels of docosahexaenoic acid (DHA), on infant health outcomes is unclear. Part of the reason for this is difficulties in collecting, storing and shipping milk samples to the laboratory. Here we report the validation of a dried milk spot (DMS) system to measure FA composition to help overcome these obstacles. Milk FA were measured by gas chromatography and reported as percent of total FA; the FA of primary interest in this study were DHA and industrially produced trans FA (iTFA). Experiments were carried out using pooled milk samples from US (n = 5) and Malawian women (n = 50). Experiments compared liquid vs. DMS samples (n = 55), assessed stability of FA composition under different storage conditions (n = 5), and compared the results from two different labs using the same methods (n = 5).
Both % DHA and % iTFA levels in liquid and DMS samples were strongly correlated (R(2) = 0.99 and 0.99, respectively, P < 0.0001). The % DHA in DMS samples was stable for up to four weeks at room temperature and up to three years at -80 °C; only slight deviations from the acceptable range of variability (±15 %) occurred in the 4 °C and -20 °C conditions for % DHA. The % iTFA was stable under all conditions. All % DHA and % iTFA were within 15 % of the referent when analyzed in two laboratories.
Valid FA composition values can be obtained from DMS samples using this robust collection and transport system which should facilitate studies of the role of milk FA composition in infant development.
母乳脂肪酸（FA）组成，尤其是二十二碳六烯酸（DHA）水平对婴儿健康结局的影响尚不清楚。部分原因在于将乳汁样本采集、储存并运送至实验室存在困难。在此，我们报告一种用于测量FA组成的干奶斑（DMS）系统的验证情况，以帮助克服这些障碍。通过气相色谱法测量乳汁FA，并报告为总FA的百分比；本研究主要关注的FA为DHA和工业生产的反式脂肪酸（iTFA）。使用来自美国（n = 5）和马拉维女性（n = 50）的混合乳汁样本进行实验。实验比较了液体样本与DMS样本（n = 55），评估了不同储存条件下FA组成的稳定性（n = 5），并比较了两个不同实验室使用相同方法得出的结果（n = 5）。
液体样本和DMS样本中的DHA百分比和iTFA百分比均呈强相关（R²分别为0.99和0.99，P < 0.0001）。DMS样本中的DHA百分比在室温下长达四周以及在 -80°C下长达三年均保持稳定；在4°C和 -20°C条件下，DHA百分比仅出现轻微偏离可接受变异范围（±15%）的情况。iTFA百分比在所有条件下均保持稳定。在两个实验室进行分析时，所有DHA百分比和iTFA百分比均在参考值的15%以内。
使用这种强大的采集和运输系统可从DMS样本中获得有效的FA组成值，这应有助于对乳汁FA组成在婴儿发育中的作用开展研究。
