Department of Food and Nutritional Sciences, University of Reading, Whiteknights, PO Box 226, Reading, RG6 6AP, UK.
Eur J Nutr. 2013 Feb;52(1):389-95. doi: 10.1007/s00394-012-0328-2. Epub 2012 Mar 10.
Meat and fish consumption are associated with changes in the risk of chronic diseases. Intake is mainly assessed using self-reporting, as no true quantitative nutritional biomarker is available. The measurement of plasma fatty acids, often used as an alternative, is expensive and time-consuming. As meat and fish differ in their stable isotope ratios, δ(13)C and δ(15)N have been proposed as biomarkers. However, they have never been investigated in controlled human dietary intervention studies.
In a short-term feeding study, we investigated the suitability of δ(13)C and δ(15)N in blood, urine and faeces as biomarkers of meat and fish intake.
The dietary intervention study (n = 14) followed a randomised cross-over design with three eight-day dietary periods (meat, fish and half-meat-half-fish). In addition, 4 participants completed a vegetarian control period. At the end of each period, 24-h urine, fasting venous blood and faeces were collected and their δ(13)C and δ(15)N analysed.
There was a significant difference between diets in isotope ratios in faeces and urine samples, but not in blood samples (Kruskal-Wallis test, p < 0.0001). In pairwise comparisons, δ(13)C and δ(15)N were significantly higher in urine and faecal samples following a fish diet when compared with all other diets, and significantly lower following a vegetarian diet. There was no significant difference in isotope ratio between meat and half-meat-half-fish diets for blood, urine or faecal samples.
The results of this study show that urinary and faecal δ(13)C and δ(15)N are suitable candidate biomarkers for short-term meat and fish intake.
肉类和鱼类的摄入与慢性病风险的变化有关。摄入量主要通过自我报告来评估，因为目前还没有真正的定量营养生物标志物。血浆脂肪酸的测量，通常作为替代方法，既昂贵又费时。由于肉类和鱼类的稳定同位素比值不同，δ(13)C 和 δ(15)N 已被提议作为生物标志物。然而，它们从未在受控的人类饮食干预研究中进行过研究。
在一项短期喂养研究中，我们研究了血液、尿液和粪便中的 δ(13)C 和 δ(15)N 作为肉类和鱼类摄入量的生物标志物的适用性。
该饮食干预研究（n = 14）采用随机交叉设计，包括三个为期 8 天的饮食期（肉类、鱼类和半肉半鱼）。此外，4 名参与者完成了素食对照期。在每个时期结束时，收集 24 小时尿液、空腹静脉血和粪便，并分析其 δ(13)C 和 δ(15)N。
在粪便和尿液样本中，饮食之间的同位素比值存在显著差异，但在血液样本中没有（Kruskal-Wallis 检验，p < 0.0001）。在两两比较中，与所有其他饮食相比，鱼类饮食后尿液和粪便样本中的 δ(13)C 和 δ(15)N 显著升高，而素食饮食后则显著降低。血液、尿液或粪便样本中，肉类和半肉半鱼饮食之间的同位素比值无显著差异。
本研究结果表明，尿液和粪便中的 δ(13)C 和 δ(15)N 是短期肉类和鱼类摄入的合适候选生物标志物。
