Fig. 7.

Levels of AA-Val (upper panel) and GA-Val (lower panel) in non-smoking omnivore (red boxes, n = 19) and vegan (grey boxes, n = 20) study participants in 2017 (left columns) and in 2021 (right columns). Lines and boxes represent median values and the lower and upper quartiles, respectively, and the error bars represent the 10th and 90th percentiles. The significance of adduct level differences is noted with asterisks (*p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, Mann–Whitney rank-sum test for the difference between vegans and omnivores and Wilcoxon signed-rank test for the pairwise difference between the data determined in 2017 and 2021)