Evidence for a possible dietary effect on the isotopic composition of Zn in blood via isotopic analysis of food products by multi-collector ICP-mass spectrometry

Abstract

In this work, the hypothesis of a possible dietary effect on the isotopic composition of Zn in blood from populations with different feeding habits, i.e. lacto-ovo vegetarians and omnivores, was investigated through isotopic analysis of Zn in common food products by multi-collector ICP - mass spectrometry (MC-ICP-MS). Several certified reference materials (CRMs) were also included in the sample set for comparison purposes. For these CRMs, the isotopic composition of Zn is expressed as δ-values, calculated with respect to both IRMM-3702 and JMC-ZnLyon, as isotopic standards. The range of δ(66)Zn values observed in food products was approximately 1.9‰. In general, vegetables, cereals and derived products showed an enrichment of the heavier Zn isotopes, whereas a depletion was observed in products of animal origin (meat, fish, egg and semi-skimmed milk), relative to human blood samples. Mussel, however, showed a significant enrichment of the heavier isotopes, which is hypothetically attributed to its accumulation behaviour. Thus, the lower δ(66)Zn values found in food products of animal origin appear to be reflected in the lower δ(66)Zn value observed in blood from an omnivorous population compared to that for a vegetarian population.