Effect of seafood mediated PCB exposure on desaturase activity and PUFA profile in Faroese septuagenarians

Abstract

Polychlorinated biphenyl (PCB) exposure may affect serum concentrations of polyunsaturated fatty acids (PUFAs) by inhibiting desaturases Δ5 and Δ6 that drive their synthesis from precursor fatty acids. Such changes in the composition of fatty acids may affect cardiovascular disease risk, which is thought to increase at elevated PCB exposures. This population-based cross-sectional study examined 712 Faroese men and women aged 70–74 years. The serum phospholipid fraction of fasting blood samples was used to determine the PUFA profile, including linoleic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosatrienoic acid, and other relevant fatty acids. Ratios between precursor and metabolite fatty acids were used as proxies for Δ5 and Δ6 desaturase activity. Tertiles of serum-PCB concentrations were used in multiple regression analyses to determine the association between the exposure and desaturase activity. In multiple regression models, PCB exposure was inversely related to the estimated Δ6 desaturase activity resulting in accumulation of precursor fatty acids and decrease in the corresponding product PUFAs. A positive association between PCB and Δ5 desaturation was also found. A relative increase in EA was also observed, though only in the third tertile of PCB exposure. Non-linear relationships between the exposure and the desaturase activity were not found. Consuming fish and seafood may not be translated into beneficial fatty acid profiles if the diet simultaneously causes exposure to PCBs. Although the desaturase estimates were likely influenced by dietary intakes of product PUFAs, the association between PCB exposure and Δ6 desaturase activity is plausible and may affect cardiovascular disease risk.

Networks of placental DNA methylation correlate with maternal serum PCB concentrations and child neurodevelopment

“…Lastly, the multiple linear regression models showed that PCB 180 + 193 serum levels are predicted by maternal plasma polyunsaturated fatty acid levels. PCBs have previously been associated with polyunsaturated fatty acids in human serum due to the high prevalence of both PCBs and PUFAs in fish and fish oil ( Ashley et al, 2013 ; Bourdon et al, 2010 ; Dellinger et al, 2018 ; Ge et al, 2019 ; Tøttenborg et al, 2015 ). However, we did not include dietary information in this study, so cannot validate a hypothesis for the association between PCB 180 + 193 and dietary polyunsaturated fatty acid intake.…”

Interactions between environmental pollutants and dietary nutrients: current evidence and implications in epidemiological research

“…38 These findings were supported in a birth cohort study conducted in the Faroe Islands where the cord serum levels of PCBs were inversely associated with the concentrations of AA 39 and in a cohort of elderly people where the PCB levels in serum were also inversely related to the estimated Δ6 desaturase activity and larger concentrations of fatty acids precursors. 40 Uptake, storage and transport of dietary vitamin A and its related congeners (ie, β-carotene and retinyl esters) are regulated by the retinoid system, target of multiple endocrine-disrupting chemicals including dioxins, PCBs or pesticides. Given the fundamental role of retinoids in multiple physiological processes, the perturbation of vitamin A metabolism has been suggested as a putative mechanism triggering or mediating POPs-induced adverse health effects related to the immune system function, reproduction or development.…”