Urinary trace element levels in vegans compared to lacto-ovo-vegetarians and omnivores

Studies assessing potential differences in trace element status among vegans, lacto-ovo-vegetarians (LOV), and omnivores (OMN) are largely lacking. In this cross-sectional study, urinary levels of 12 elements were analysed in 38 vegans, 37 LOV, and 40 OMN. After adjustment for covariates, non-creatinine-adjusted arsenic levels were lower in LOV (-54%) and vegans (-54%) compared to OMN (p = 0.009). Compared to OMN, vegans (but not LOV) had lower mercury (-48%; p = 0.028) and higher cadmium levels (+42%; p = 0.023). Other elements (aluminium, cobalt, copper, lead, molybdenum, nickel, thallium, tin, and zinc) were similar between groups. Analyses normalised to urinary creatinine confirmed lower arsenic levels in LOV (-63%) and vegans (-59%; p<0.001), but suggested similar mercury and cadmium levels in OMN, LOV, and vegans, higher cobalt in LOV (+53%; p = 0.035), and higher copper in vegans (+17%; p = 0.040). Trends (non-significant after adjustment for multiple testing) were noted for nickel (LOV: +119%), cobalt (vegans: +43%), and zinc (vegans: -26%; compared to OMN). LOV and vegans had similar urinary levels (p ≥0.207). Urinary creatinine levels were similar across all groups (p ≥0.912). Eight additional elements were not detected (bismuth, gold, indium, iridium, palladium, silver) or were detected only in a few samples (platinum, zirconium). Overall, LOV and vegans exhibited a lower arsenic burden than OMN. A higher cadmium and lower mercury burden in vegans was not confirmed in creatinine-adjusted analyses. Similar studies are warranted to validate results. Biomonitoring studies may benefit from considering vegetarian status, particularly for arsenic exposure.