High Cadmium Accumulation Among Humans and Primates: Comparison Across Various Mammalian Species—A Study from Japan

Abstract

The majority of existing literature reports that cadmium (Cd) is toxic to humans and most living organisms. This paper reports the results of our study that measured Cd levels in the livers and kidneys of humans and other 50 mammalian species under normal conditions in Japan. The study tests the differences in the Cd concentrations across different mammalian species and sexes. Our results revealed that (1) there is a strong correlation between the Cd levels in the livers and kidneys across all examined species, (2) humans exhibit the highest Cd accumulation level in both organs, (3) primates also show a high Cd concentration at a level close to humans, (4) mice and rats show low Cd levels in both organs, indicating that humans accumulate about a few thousand times more Cd than mice and rats, and (5) the Cd concentration of female mammals is more than double of males for both organs. Our results indicate that these cross-sex as well as cross-species discrepancies cannot be explained by the difference in daily Cd intake. While further research is necessary to determine any potential role of Cd accumulation, we speculate that Cd plays some physiological function in the renal cortex of humans and primates.

Differential sensitivity and responsiveness of three human cell lines HepG2, 1321N1 and HEK 293 to cadmium

“…However, exposure to Cd can also result in enhanced activities of heme oxygenase (Koizumi et al, 2008), metallothionein (Durnam and Palmiter, 1981), and heat shock proteins (Williams and Morimoto, 1990). This adaptive response is mediated through changes in transcription (Koizumi, et al, 2008), most likely via the interaction of the transcription factor Nrf2 with an Antioxidant Response Element (He et al, 2008) or through other pathways using factors such as Ap1 (Liu et al, 2002) and NFҚB (Yang et al, 2007a). The involvement of Nrf2 in mediating the observed responses to Cd, particular the elevation in GPx and AKR activities is currently the focus of further investigations.…”

Trace element compositional changes in human milk during the first four months of lactation

“…In fact, many chemicals can be transferred from both the body reserves and the blood into the breast milk of a lactating mother. In this respect, the levels of toxic metals in milk are of significance (Koizumi et al, 2008;Wappelhorst et al, 2002). Cadmium, lead, arsenic and aluminium are of considerable interest due to their toxicity and widespread use Al-Saleh et al, 2003;García-Esquinas et al, 2011;Honda et al, 2003;Rahimi et al, 2009).…”

Cadmium, Lead, Copper and Zinc in Breast Milk in Poland

“…However, mother's milk can also be a source of cadmium (Cd) and lead (Pb) for a baby. The content of these elements in breast milk reflects the level of environmental pollution and the mother's diet [5–8]. The presence of these metals in food products has become a global problem [5, 9, 10].…”