Concern has been expressed regarding the effects of exposure of human population to methylmercury through fish consumption. Lipid peroxidation is regulated by the level of free radicals, the availability of pro-oxidative catalytic transition metals as well as antioxidative defense including seleno-gluthatione peroxidase (seleno-GPx) and glutathione reductase (GR).

OBJECTIVES: 1)to determine the levels of exposure of an Inuit population of Salluit, Nunavik, (n=117) to environmental contaminants and 2) to determine the lipid profiles as well as the oxidative status using oxidative stress markers such as oxidized LDL (oxLDL), seleno-GPx and GR.

METHODS: Mercury (Hg) and selenium (Se) have been measured by atomic absorption and graphite furnace atomic absorption respectively. Lipoproteins, isolated by ultracentrifugation, have been analyzed by standard enzymatic and immunological assays. Seleno-GPx and GR activities and glutathione levels have been measured by enzymatic assays. Erythrocyte fatty acid profiles have been determined by gas chromatography.

RESULTS: Hair Hg and blood Se were respectively 15- and 7-fold higher than reported in the general population. Their lipoprotein profiles (M/F 35/82, age 45±13 y, BMI 29.4±6.6 kg/m², mean ± SD) were found to be normal:C 5.52±1.11 mM, Tg 1.23±0.58 mM, LDL-C 3.16±0.95 mM and HDL-C 1.42±0.41 mM. OxLDL was significantly lower than normal (1.6X, p<0.0001). Erythrocyte n-3 fatty acids were 2 to 6 fold higher than Caucasian controls whereas GPx and GR activities were increased (p<0.0001).

CONCLUSION: Despite the high exposure to Hg, high prevalence of obesity and smoking, the mortality rate of CVD remains extremely low among Inuits of Nunavik, most likely because of their traditional diet rich in n-3 fatty acids and Se. IRST and Health Canada.

DNC

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