Fertilizer Type Affects Stable Isotope Ratios of Nitrogen in Human Blood Plasma─Results from Two-Year Controlled Agricultural Field Trials and a Randomized Crossover Dietary Intervention Study

Abstract

The stable nitrogen isotope ratio δ 15 N is used as a marker of dietary protein sources in blood. Crop fertilization strategies affect δ 15 N in plant foods. In a double-blinded randomized cross-over dietary intervention trial with 33 participants, we quantified the effect of fertilizer type (conventional: synthetic fertilizer and organic: animal or green manure) on δ 15 N in blood plasma. At study baseline, plasma δ 15 N was +9.34 ± 0.29‰ (mean ± standard deviation). After 12 days intervention with a diet based on crops fertilized with animal manure, plasma δ 15 N was shifted by +0.27 ± 0.04‰ (mean ± standard error) compared to synthetic fertilization and by +0.22 ± 0.04‰ compared to fertilization with green manure (both p < 0.0001). Accordingly, differences in the δ 15 N values between fertilizers are propagated to the blood plasma of human consumers. The results indicate a need to consider agricultural practices when using δ 15 N as a dietary biomarker.

Bulk and Compound-Specific Stable Isotope Analysis for the Authentication of Walnuts (Juglans regia) Origins

“…25 Synthetic fertilizer is commonly produced via the Haber−Bosch reaction that relies on nitrogen fixation from the atmosphere; therefore, the δ 15 N values are close to 0‰. Green manure from legumes also exhibits nitrogen values near atmophere; however, animal manure and compost undergo more complex biochemical reactions resulting in higher δ 15 N. 55 Thus, we hypothesized that the samples from other countries besides China and the USA used compost or animal manure.…”

Rapid characterization of isotopic purity of deuterium‐labeled organic compounds and monitoring of hydrogen–deuterium exchange reaction using electrospray ionization‐high‐resolution mass spectrometry

“…Therefore, the isotope labeling approach also serves as a measure of artificially changing the isotopic composition ratio of products 7 . To date, isotopic purity is also widely applied for identification and differentiation of drugs in many research fields such as metabolomics, 8 agriculture, 9 environment, 10 food, 11 and forensic sciences 12 …”

“…6 Therefore, the isotope labeling approach also serves as a measure of artificially changing the isotopic composition ratio of products. 7 To date, isotopic purity is also widely applied for identification and differentiation of drugs in many research fields such as metabolomics, 8 agriculture, 9 environment, 10 food, 11 and forensic sciences. 12 With the rapid development of analytical instruments and increasing requirements under new trends, the use of isotopic purity characterization methods has substantially increased.…”