Selenium deficiency in Yugoslavia and possible effects on health

Multiple geochemical factors may cause iodine and selenium deficiency in Gilgit-Baltistan, Pakistan

Deficiencies of the micronutrients iodine and selenium are particularly prevalent where populations consume local agricultural produce grown on soils with low iodine and selenium availability. This study focussed on such an area, Gilgit-Baltistan in Pakistan, through a geochemical survey of iodine and selenium fractionation and speciation in irrigation water and arable soil. Iodine and selenium concentrations in water ranged from 0.01-1.79 µg L^-1 to 0.016-2.09 µg L^-1, respectively, which are smaller than levels reported in similar mountainous areas in other parts of the world. Iodate and selenate were the dominant inorganic species in all water samples. Average concentrations of iodine and selenium in soil were 685 µg kg^-1 and 209 µg kg^-1, respectively, much lower than global averages of 2600 and 400 µg kg^-1, respectively. The 'reactive' fractions ('soluble' and 'adsorbed') of iodine and selenium accounted for < 7% and < 5% of their total concentrations in soil. More than 90% of reactive iodine was organic; iodide was the main inorganic species. By contrast, 66.9 and 39.7% of 'soluble' and 'adsorbed' selenium, respectively, were present as organic species; inorganic selenium was mainly selenite. Very low distribution coefficients (kd = adsorbed/soluble; L kg^-1) for iodine (1.07) and selenium (1.27) suggested minimal buffering of available iodine and selenium against leaching losses and plant uptake. These geochemical characteristics suggest low availability of iodine and selenium in Gilgit-Baltistan, which may be reflected in locally grown crops. However, further investigation is required to ascertain the status of iodine and selenium in the Gilgit-Baltistan food supply and population.

Selenium and other mineral concentrations in feed and sheep's blood in Kosovo

The aim of this study was to assess the concentration of Se and other minerals in sheep and the supplied feed. Four macrominerals (Ca, P, Mg, and S), 7 microminerals (Se, Fe, Zn, Cu, Mn, Co, and Mo), and 2 toxic minerals (Cd and Pb) were analyzed in 69 feed and 292 sheep blood samples from 30 farms in different regions of Kosovo. The samples were analyzed using inductively coupled plasma mass spectrometry, and mineral concentrations in whole blood were measured to assess their status in animals. Concentrations of the different minerals in feed were found in the following ranges: 1.9 to 9.5 g Ca/kg DM, 0.8 to 3.2 g P/kg DM, 0.8 to 3.2 g Mg/kg DM, 1.0 to 2.8 g S/kg DM, 6 to 82 µg Se/kg DM, 33 to 970 mg Fe/kg DM, 15 to 42 mg Zn/ kg DM, 2.6 to 7.5 mg Cu/kg DM, 26 to 250 mg Mn/kg DM, 0.04 to 0.88 mg Co/kg DM, 0.05 to 0.86 mg Mo/ kg DM, 0.07 to 2.02 mg Pb/kg DM, and 0.02 to 0.19 mg Cd/kg DM. Concentrations of the microminerals analyzed in whole blood were found in the following ranges: 15 to 360 µg Se/L, 190 to 500 mg Fe/L, 1.4 to 3.8 mg Zn/L, 0.3 to 2.6 mg Cu/L, 6 to 243 µg Mn/L, 0.1 to 19.6 µg Co/L, and 1.8 to 66.0 µg Pb/L. Among all minerals, the largest deficiency was found for Se both in feed and sheep blood, with 82% of feed samples and 83% blood samples being inadequate, and its supplementation is necessary. Selenium-supplemented sheep had significantly higher Se concentration in blood than non-supplemented sheep (P < 0.01). In addition, other macro- and microminerals in feed such as P, S, Cu, and Co were at inadequate concentrations at some of the farms, and supplementation may also be needed for these minerals.

Selenium in global food systems

Food systems need to produce enough of the essential trace element Se to provide regular adult intakes of at least 40 μg/d to support the maximal expression of the Se enzymes, and perhaps as much as 300 μg/d to reduce risks of cancer. Deprivation of Se is associated with impairments in antioxidant protection, redox regulation and energy production as consequences of suboptimal expression of one or more of the Se-containing enzymes. These impairments may not cause deficiency signs in the classical sense, but instead contribute to health problems caused by physiological and environmental oxidative stresses and infections. At the same time, supranutritional intakes of Se, i.e. intakes greater than those required for selenocysteine enzyme expression, appear to reduce cancer risk. The lower, nutritional, level is greater than the typical intakes of many people in several parts of the world, and few populations have intakes approaching the latter, supranutritional, level. Accordingly, low Se status is likely to contribute to morbidity and mortality due to infectious as well as chronic diseases, and increasing Se intakes in all parts of the world can be expected to reduce cancer rates.

Blood selenium and glutathione peroxidases in miscarriage

OBJECTIVE

To investigate the selenium glutathione and glutathione peroxidase (glutathione-Px) levels in blood in women who experience miscarriage.

DESIGN

An observational study.

PARTICIPANTS

Forty women with miscarriage occurring in the first and second trimesters.

METHODS

Concentrations were measured in whole blood and plasma. Glutathione was measured in red cells and glutathione-Px activity was measured in the red cells and plasma. The results were compared with 36 women in the same period of viable pregnancy and 28 age-matched, healthy, non-pregnant controls.

RESULTS

The selenium concentrations in whole blood and plasma of women following abortion were the same as in viable pregnancy, but were significantly lower compared with controls. The glutathione levels were significantly higher in women with miscarriage compared with viable pregnancies and with non-pregnant women. Red cell and plasma glutathione-Px activities of women who had had a miscarriage were significantly lower than in both normal pregnancies and the control group.

CONCLUSION

The decreased activities of the antioxidant enzymes, red cell and plasma glutathione-Px, may play an important role in the aetrology of spontaneous abortion.

Selenium status in Saudi Arabia

Selenium (Se) is a naturally occurring trace element that is essential for animal and human nutrition, but the range between dietary requirements and toxic levels is relatively narrow. In this review, we are interested in the beneficial effects of selenium and we report on a number of studies of the selenium status of different populations in Saudi Arabia. The Status reflects the geographical area inhabited by the populations. Apart from the few available studies reviewed here, no data on the human status of Se in Saudi Arabia has been obtained. A further objective of this paper is throw some the light on the direction of future studies.