Nutrition Innovation Centre for Food and Health (NICHE), University of Ulster, Cromore Road, Coleraine BT52 1SA, UK.
LGC, Queens Road, Teddington, Middlesex TW11 0LY, UK.
Nutrients. 2018 Mar 1;10(3):287. doi: 10.3390/nu10030287.
Cow's milk is the most important dietary source of iodine in the UK and Ireland, and also contributes to dietary selenium intakes. The aim of this study was to investigate the effect of season, milk fat class (whole; semi-skimmed; skimmed) and pasteurisation on iodine and selenium concentrations in Northern Ireland (NI) milk, and to estimate the contribution of this milk to consumer iodine and selenium intakes. Milk samples (unpasteurised, whole, semi-skimmed and skimmed) were collected weekly from two large NI creameries between May 2013 and April 2014 and were analysed by inductively coupled plasma-mass spectrometry (ICP-MS). Using milk consumption data from the National Diet and Nutrition Survey (NDNS) Rolling Programme, the contribution of milk (at iodine and selenium concentrations measured in the present study) to UK dietary intakes was estimated. The mean ± standard deviation (SD) iodine concentration of milk was 475.9 ± 63.5 µg/kg and the mean selenium concentration of milk was 17.8 ± 2.7 µg/kg. Season had an important determining effect on the iodine, but not the selenium, content of cow's milk, where iodine concentrations were highest in milk produced in spring compared to autumn months (534.3 ± 53.7 vs. 433.6 ± 57.8 µg/kg, respectively; = 0.001). The measured iodine and selenium concentrations of NI milk were higher than those listed in current UK Food Composition Databases (Food Standards Agency (FSA) (2002); FSA (2015)). The dietary modelling analysis confirmed that milk makes an important contribution to iodine and selenium intakes. This contribution may be higher than previously estimated if iodine and selenium (+25.0 and +1.1 µg/day respectively) concentrations measured in the present study were replicable across the UK at the current level of milk consumption. Iodine intakes were theoretically shown to vary by season concurrent with the seasonal variation in NI milk iodine concentrations. Routine monitoring of milk iodine concentrations is required and efforts should be made to understand reasons for fluctuations in milk iodine concentrations, in order to realise the nutritional impact to consumers.
牛奶是英国和爱尔兰碘的最重要膳食来源，也是膳食硒摄入量的来源之一。本研究的目的是调查季节、牛奶脂肪含量（全脂、半脱脂、脱脂）和巴氏杀菌对北爱尔兰（NI）牛奶中碘和硒浓度的影响，并估计这种牛奶对消费者碘和硒摄入量的贡献。2013 年 5 月至 2014 年 4 月，从两家大型 NI 乳品厂每周采集未经过巴氏杀菌的全脂、半脱脂和脱脂牛奶样品，并通过电感耦合等离子体质谱法（ICP-MS）进行分析。利用国家饮食与营养调查（NDNS）滚动计划中的牛奶消费数据，估计了牛奶（根据本研究中测量的碘和硒浓度）对英国饮食摄入量的贡献。牛奶中碘的平均浓度±标准偏差（SD）为 475.9 ± 63.5 µg/kg，牛奶中硒的平均浓度为 17.8 ± 2.7 µg/kg。季节对牛奶中碘的含量有重要的决定作用，但对硒的含量没有影响，与秋季相比，春季生产的牛奶中碘含量更高（分别为 534.3 ± 53.7 vs. 433.6 ± 57.8 µg/kg； = 0.001）。NI 牛奶中测量的碘和硒浓度高于当前英国食品成分数据库（食品标准局（FSA）（2002 年）；FSA（2015 年））中列出的浓度。饮食建模分析证实，牛奶对碘和硒的摄入量有重要贡献。如果本研究中测量的碘和硒（分别为+25.0 和+1.1 µg/天）浓度在当前牛奶消费水平下在英国各地具有可重复性，则这种贡献可能高于以前的估计。理论上，碘摄入量随季节变化而变化，与 NI 牛奶碘浓度的季节性变化一致。需要对牛奶碘浓度进行常规监测，并应努力了解牛奶碘浓度波动的原因，以实现对消费者的营养影响。
