Selenium and vitamins status in Saudi children

BACKGROUND: Selenium is an essential element, and a cofactor required to maintain glutathione peroxidase activity. Its deficiency may induce modification in the cellular antioxidative status and the appearance of different diseases. Previous studies in Al-Kharj reported low selenium levels in the soil and the milk of lactating mothers living in that area. METHODS: A cross-sectional study was carried out to determine the status of selenium, dl-alpha-tocopherol, and all-trans-retinol in 513 Saudi children living in Al-Kharj district using serum and toenail samples. RESULTS: The prevalence of children with serum selenium below the threshold limit of clinical importance in coronary and cardiovascular diseases (45 microg/l) was only 1.4%, while 53.4% of the tested children had toenail selenium >0.56 microg/g, which is considered a low level as indicated in a previous study. DL-alpha-tocopherol deficiency (<0.5 mg/dl) was found only in 3.1%. However, none of the children in this study had a severe all-trans-retinol deficiency (<10 microg/dl) and the percentage of children with marginal deficiency <20 microg/dl was 5.5%. CONCLUSION: It seems that the geographical location of primary health care units (PHCUs) is the most important factor in influencing the selenium status of these children. This implies variations in food habits. Serum and toenail selenium concentrations were significantly related which can both reflect dietary selenium intake. Although our results suggest an adequate vitamin A status, we found interestingly that 10.9% of the children had retinol >50 microg/dl. This suggests that a high dietary intake of vitamin A might have a harmful effect. Further work is necessary to determine whether the hypervitaminosis A in children reflects an excessive dietary intake of retinol. A significant negative association was also found between dl-alpha-tocopherol and all-trans-retinol and malonaldehyde (MDA) levels in the serum of children population. This confirms their role in reducing oxidative stress.