Poster Topical Area: Vitamins and Minerals
Location: Hall D
Poster Board Number: 511
High methylmercury (MeHg) irreversibly inhibits selenium (Se)-dependent enzymes that are required to prevent and reverse oxidative damage in the brain. Dietary Se intakes are usually in significant molar excess of MeHg exposures from ocean fish consumption and are therefore sufficient to prevent Hg-dependent interruption of selenoenzyme activities and synthesis. This appears to explain why epidemiological studies effects have not found adverse effects on child health outcomes associated with maternal Hg exposures except among populations which consume certain rarely consumed seafoods such as pilot whale meats. Because Se is the pivotal determinant of Hg's effects, the Health Benefit Value (HBV) was developed as more reliable criterion for predicting the effects expected to accompany Hg exposures. It is calculated; HBV = ((Se – Hg)/Se) x (Hg + Se) on a molar concentration basis. A negative HBV indicates Hg is present in molar excess of Se and can potentially impede Se availability in the consumer, while a positive HBV indicates the amount of Se available in excess of Hg exposures. To assess potential risks or benefits associated with consumption, this study assessed the Hg and Se molar concentrations to establish the HBV of pilot whale, mako shark, thresher shark, swordfish, bigeye tuna, and skipjack tuna in relation to body weights to differentiate seafoods which are safe and beneficial to consume during pregnancy from those which may be associated with risk.
The concentrations of Hg and Se of pilot whale, mako shark, thresher shark, swordfish, bigeye tuna, and skipjack tuna were assessed in relation to their body weights, and the HBV's and relative Se deficits or surplus that would accompany their consumption were calculated.
We found the HBV's of adult pilot whales and mako sharks were uniformly negative and grew more negative as body size increased. The HBVs of Swordfish are increasingly negative in larger specimens, and should also be avoided during pregnancy. However, the HBVs of thresher shark, bigeye tuna, and skipjack tuna were uniformly positive.
The HBV provides a biochemical basis that more reliably indicates which types of ocean fish should be avoided to minimize Hg-risks or recommended for maternal consumption during pregnancy.
University of North Dakota
Grand Forks, North Dakota