Selenium supplementation of children in a selenium-deficient area in China- Blood selenium levels and glutathione peroxidase activities

Keshan disease is a cardiomyopathy restricted to the endemic areas of China and seen in residents having an extremely low selenium (Se) status. Prophy lactic administration of sodium selenite has been shown to decrease signifi cantly the incidence of acute and subacute cases. The aim of the study was to assess the relative bioavailability of selenite versus organic Se-yeast in a Se-deficient area in China with a randomized double-blind double-dummy design. Healthy children (n=30) between 14 and 16 yr of age were randomized into th ree equal groups receiving either 200 mu g/d selenite Se or 200 mu g/d Se-y east or placebo for 12 wk. Blood was drawn at baseline, 4, 8, and 12 wk and 4 wk postsupplementation. The plasma Se concentration (mean +/- SD) was 0. 16+/-0.03 mu mol/L at baseline. Selenite and Se-yeast supplementation incre ased plasma Se to plateau values, 1.0 +/- 0.2 and 1.3 +/- 0.2 mu mol/L, res pectively. In red cells, Se-yeast increased the selenium level sixfold and selenite threefold compared to placebo. The relative bioavailability of Se- yeast versus selenite measured as glutathione peroxidase (GSHPx) activity w as similar in plasma, red blood cells, and platelets. GSHPx activity reache d maximal levels in plasma and platelets of 300% and 200%, respectively, af ter 8 wk compared to the placebo group, but continued to increase in red ce lls for 16 wk. Our study showed that although both forms of Se were equally effective in r aising GSHPx activity, Se-yeast provided a longer lasting body pool of Se. Se-yeast may be a better alternative to selenite in the prophylaxis of Kesh an disease with respect to building up of body stores.