Skip to main content
. 2023 Aug 11;15(16):3538. doi: 10.3390/nu15163538

Figure 3.

Figure 3

Analysis of copper biomarkers at baseline. (A) Total copper concentrations in the serum of omnivores (WD, n = 40), flexitarians (Flex, n = 47), vegetarians (VG, n = 45), and vegans (VN, n = 40) were determined using total reflection X-ray fluorescence spectroscopy (TXRF). The dashed lines indicate the reference range of copper in serum, with the numbers below the violin plots representing the percentage of subjects below this threshold. (B) Enzyme activity of Ceruloplasmin (CP) (WD, n = 38; Flex, n = 47; VG, n = 43; VN, n = 40) was measured by colorimetric assay. (C) Free serum copper levels were quantified by a fluorometric method using a copper-binding fluorescent peptide (FP4). (D) Daily copper intakes were calculated from baseline dietary records conducted over 5 days (WD n = 37, Flex n = 46, VG n = 39, and VN n = 38). The results are shown as median with 25- and 75-quartile range (indicated as dotted lines). Diet groups that do not share indices (a,b) differ significantly (Kruskal–Wallis test followed by Benjamini–Hochberg correction (p < 0.05)).