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

• Published in: Journal of agricultural and food chemistry 2022-03, Vol.70 (11), p.3391-3399
• Main Authors: Mie, Axel, Novak, Vlastimil, Franko, Mikael Andersson, Bügel, Susanne Gjedsted, Laursen, Kristian Holst
• Format: Article
• Language: English
• Subjects: Agricultural and Environmental Chemistry; Agriculture - methods; Animals; dietary protein; fertilizer type; Fertilizers; Humans; Manure - analysis; Nitrogen - analysis; Nitrogen Isotopes - analysis; organic rood; production system; stable nitrogen isotopes
• ISSN: 0021-8561; 1520-5118; 1520-5118
• DOI: 10.1021/acs.jafc.1c04418

The stable nitrogen isotope ratio δ15N is used as a marker of dietary protein sources in blood. Crop fertilization strategies affect δ15N 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 δ15N in blood plasma. At study baseline, plasma δ15N was +9.34 ± 0.29‰ (mean ± standard deviation). After 12 days intervention with a diet based on crops fertilized with animal manure, plasma δ15N 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 δ15N values between fertilizers are propagated to the blood plasma of human consumers. The results indicate a need to consider agricultural practices when using δ15N as a dietary biomarker.