Department of Clinical Medicine, Centre for Nutrition, Mohn Nutrition Research Laboratory, University of Bergen, Haukelandsbakken 15, 5021, Bergen, Norway.
Department of Medical Biochemistry and Pharmacology, Haukeland University Hospital, Bergen, Norway.
Eur J Nutr. 2023 Feb;62(1):433-441. doi: 10.1007/s00394-022-02992-y. Epub 2022 Sep 10.
Dietary biomarkers can potentially overcome the limitations of self-reported dietary data. While in ecology and archaeology, stable isotope ratios of carbon and nitrogen are widely used as biomarkers, this is not the case in nutrition research. Since the abundance of the 13C and the 15N isotope differ in food sources from plant and animal origin, stable isotope ratios of carbon and nitrogen (δ13C and δ15N) may differ in human biological material. Here, we investigated the stable isotope ratios of nitrogen and carbon in serum and urine from vegans and omnivores.
Measurement of δ15N and δ13C in serum and 24 h urine was performed by Elemental Analyzer-Isotope Ratio Mass Spectrometer in the cross-sectional study "Risks and Benefits of a Vegan Diet". The study included 36 vegans and 36 omnivores with a median age of 37.5 years (matched for age and sex), who adhered to their diet for at least 1 year.
Both δ15N and δ13C were significantly lower in both the serum and 24 h urine of vegans compared to omnivores. δ15N either in serum or urine had 100% specificity and sensitivity to discriminate between vegans and omnivores. Specificity of δ13C was also > 90%, while sensitivity was 93% in serum and 77% in urine.
δ15N both in serum and urine was able to accurately identify vegans and thus appears to be a promising marker for dietary habits.
饮食生物标志物有可能克服自我报告饮食数据的局限性。虽然在生态学和考古学中，碳和氮的稳定同位素比值被广泛用作生物标志物，但在营养研究中并非如此。由于来自植物和动物源的食物中 13C 和 15N 同位素的丰度不同，因此人类生物材料中的碳和氮稳定同位素比值（δ13C 和 δ15N）可能不同。在这里，我们研究了素食者和杂食者血清和尿液中的氮和碳稳定同位素比值。
在“素食的风险和益处”的横断面研究中，通过元素分析仪-同位素比质谱仪测量血清和 24 小时尿液中的 δ15N 和 δ13C。该研究包括 36 名素食者和 36 名杂食者，他们的年龄中位数为 37.5 岁（年龄和性别匹配），且至少坚持他们的饮食 1 年。
与杂食者相比，素食者的血清和 24 小时尿液中的 δ15N 和 δ13C 均显著降低。δ15N 无论是在血清还是尿液中，都具有 100%的特异性和敏感性来区分素食者和杂食者。δ13C 的特异性也超过 90%，而血清中的敏感性为 93%，尿液中的敏感性为 77%。
血清和尿液中的 δ15N 均能够准确识别素食者，因此似乎是一种有前途的饮食习惯标志物。
