title: Plasma levels of selenium-containing proteins in Inuit adults from Nunavik.
abstract: Selenium (Se) is highly abundant in marine foods traditionally consumed by Inuit of Nunavik (Northern Quebec, Canada) and accordingly, their Se intake is among the highest in the world. However, little is known regarding the biological implications of this high Se status in this Arctic indigenous population. We used a method combining affinity chromatography and inductively coupled plasma-mass spectrometry with quantification by post-column isotope dilution to determine total Se levels and concentrations of Se-containing proteins in archived plasma samples of Inuit adults who participated to the 2004 Nunavik Inuit Health Survey (N = 852). Amounts of mercury (Hg) associated with Se-containing proteins were also quantified. Results show that glutathione peroxidase 3 (GPx3), selenoprotein P (SelP) and selenoalbumin (SeAlb) represented respectively 25%, 52% and 23% of total plasma Se concentrations. In addition, small amounts of Hg co-eluted with each Se-containing protein and up to 50% of plasma Hg was associated to SelP. Total plasma Se concentrations (median = 139 μg L− 1; interquartile range (IQR) = 22.7 μg L− 1) were markedly lower and less variable than whole blood Se concentration (median = 261 μg L− 1, IQR = 166 μg L− 1). A non linear relation was observed between whole blood Se and plasma Se levels, with plasma Se concentrations leveling off at approximately 200 μg L− 1, whereas 16% and 3% of individuals exhibited whole blood concentrations higher than 500 μg L− 1 and 1000 μg L− 1, respectively. In contrast, a linear relationship was previously reported in communities consuming Brazil nuts which are rich Se, mainly present as selenomethionine. This suggests that a different selenocompound, possibly selenoneine, is present in the Arctic marine food chain and accumulates in the blood cellular fraction of Inuit.
authors: Axe santé des Populations et Pratiques Optimales en Santé, Centre de Recherche du CHU de Québec, Hôpital du Saint-Sacrement, 1050, chemin Sainte-Foy, Québec, QC G1S 4L8, Canada.
authors: Adel
authors: A
authors: Achouba
authors: Centre de Toxicologie du Québec, Institut National de santé Publique du Québec (INSPQ), 945 Wolfe, Québec, QC G1V 5B3, Canada.
authors: Pierre
authors: P
authors: Dumas
authors: Axe santé des Populations et Pratiques Optimales en Santé, Centre de Recherche du CHU de Québec, Hôpital du Saint-Sacrement, 1050, chemin Sainte-Foy, Québec, QC G1S 4L8, Canada.
authors: Nathalie
authors: N
authors: Ouellet
authors: Axe santé des Populations et Pratiques Optimales en Santé, Centre de Recherche du CHU de Québec, Hôpital du Saint-Sacrement, 1050, chemin Sainte-Foy, Québec, QC G1S 4L8, Canada; Département de Médecine Préventive et Sociale, Université Laval, Pavillon Ferdinand-Vandry, Québec, QC G1V 0A6, Canada.
authors: Mélanie
authors: M
authors: Lemire
authors: Axe santé des Populations et Pratiques Optimales en Santé, Centre de Recherche du CHU de Québec, Hôpital du Saint-Sacrement, 1050, chemin Sainte-Foy, Québec, QC G1S 4L8, Canada; Centre de Toxicologie du Québec, Institut National de santé Publique du Québec (INSPQ), 945 Wolfe, Québec, QC G1V 5B3, Canada; Département de Médecine Préventive et Sociale, Université Laval, Pavillon Ferdinand-Vandry, Québec, QC G1V 0A6, Canada. Electronic address: pierre.ayotte@inspq.qc.ca.
authors: Pierre
authors: P
authors: Ayotte
mesh_terms: D000328:Adult; D001110:Arctic Regions; D006306:Health Surveys; D006801:Humans; D004930:Inuit / Q000706:statistics & numerical data*; D011792:Quebec / Q000453:epidemiology; D012643:Selenium / Q000097:blood*; D051140:Selenoproteins / Q000097:blood*
chemical_list: D051140:Selenoproteins; D012643:Selenium
keywords: Arctic; Inuit; marine food chain; mercury; selenium; selenoproteins