Curno R, Magee E A, Edmond L M, Cummings J H
Division of Pathology and Neuroscience, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland.
Eur J Clin Nutr. 2008 Sep;62(9):1106-15. doi: 10.1038/sj.ejcn.1602822. Epub 2007 May 30.
Sulphites are widely used food additives that may damage health, hence limits are set on their use. They are excreted in urine as sulphate, along with sulphate derived from sulphur amino acids. Dietary intakes of sulphites are hard to determine, so we have tested the utility of urinary nitrogen:sulphate ratio as a biomarker of inorganic sulphur (IS) intake. Additionally we determined the half-life of ingested (34)SO(4)(2-) from its urinary excretion.
Twenty healthy adult subjects were recruited by poster advertisement, for a 24-h study where they ate specified foods, which were high in IS, in addition to their normal diet. The half-life of ingested (34)SO(4)(2-) was assessed in five healthy volunteers, given 5.9 mmols of Na(2)(34)SO(4) as a single dose and collecting all urine specimens for 72-96 h. Urine and duplicate diets from three previously conducted studies were analysed for nitrogen and sulphate content, thus expanding the range of IS intakes for evaluation.
Duplicate diets were analysed for IS content by ion exchange chromatography, while IS intake was predicted from urinary sulphate (g/day S)-(urinary nitrogen (g/day)/18.89). (32)S:(34)S ratios were determined by liquid chromatography mass spectrometry/mass spectrometry.
The range of IS intake was 1.3-37.5 mmol S/day. Actual and predicted IS intakes were mmol/day+/-s.e. 9.2+/-0.65 and 7.0+/-0.45, respectively, and were correlated r=0.60 (n=108). The mean half-life of ingested (34)SO(4)(2-) was 8.2 h.
From a 24-h urine collection, IS intake from the habitual diet can be determined for groups of individuals. To predict individual intakes of IS, which may include high sporadic amounts from beer and wine, at least 48 h of urine collection would be required.
亚硫酸盐是广泛使用的食品添加剂，可能损害健康，因此对其使用设定了限制。它们与来自含硫氨基酸的硫酸盐一起以硫酸盐形式经尿液排出。饮食中亚硫酸盐的摄入量很难确定，因此我们测试了尿氮：硫酸盐比值作为无机硫（IS）摄入量生物标志物的效用。此外，我们根据尿排泄情况确定了摄入的（34）SO4（2-）的半衰期。
通过张贴海报招募了20名健康成年受试者，进行为期24小时的研究，期间他们除正常饮食外，还食用了特定的富含IS的食物。在5名健康志愿者中评估摄入的（34）SO4（2-）的半衰期，给他们单次服用5.9毫摩尔的Na2（34）SO4，并收集72 - 96小时的所有尿液样本。分析了之前三项研究中的尿液和双份饮食的氮和硫酸盐含量，从而扩大了用于评估的IS摄入量范围。
通过离子交换色谱法分析双份饮食中的IS含量，而IS摄入量通过尿硫酸盐（克/天硫）-（尿氮（克/天）/18.89）来预测。通过液相色谱质谱/质谱法测定（32）S：（34）S比值。
IS摄入量范围为1.3 - 37.5毫摩尔硫/天。实际和预测的IS摄入量分别为毫摩尔/天±标准误9.2±0.65和7.0±0.45，相关性r = 0.60（n = 108）。摄入的（34）SO4（2-）的平均半衰期为8.2小时。
通过收集24小时尿液，可以确定个体群体习惯性饮食中的IS摄入量。要预测个体的IS摄入量，其中可能包括来自啤酒和葡萄酒的大量偶发摄入量，则至少需要收集48小时的尿液。
