High-precision Cu isotopic analysis of human dietary Cu sources via multi-collector ICP-mass spectrometry

The disruption of Cu homeostasis is associated with the pathogenesis of many diseases and can result in alterations in Cu isotope fractionation. Changes in the Cu isotope ratio (⁶⁵Cu/⁶³Cu) of body fluids and tissues have been observed in liver disorders, cancers, and other diseases, displaying diagnostic/prognostic potential. However, it is not entirely clear whether certain physiological or lifestyle factors may also influence the bodily Cu isotopic composition, potentially obfuscating the signature of the pathology. To ascertain whether differences exist between food products, the Cu isotopic composition of 29 significant dietary Cu sources has been determined for the first time. The general enrichment of Cu and its heavy isotope, ⁶⁵Cu, in legumes, nuts, and seeds (major Cu sources in plant-based diets) was revealed, suggesting that individuals with plant-based diets may have a bodily Cu isotopic composition offset from that of individuals with omnivorous diets, thus requiring controlling for in study design.