Selenium concentration and glutathione peroxidase activity in blood of New Zealand infants and children.

The blood selenium (Se) concentrations of New Zealand children were lower than those reported for children living in other countries. This low blood Se was primarily determined by the low dietary intake of the children which, in turn, reflects the low Se content of New Zealand soils. Blood Se also varied geographically, with age, and with differences in quantities and types of food eaten. Children with phenylketonuria and maple syrup urine disease on synthetic diets had low Se intakes and blood Se concentrations compared with children on normal diets, and blood Se was seen to decrease with the length of time on these diets. A strong correlation (r = 0.62, P less than 0.001) was found between the blood Se levels and glutathione peroxidase activities for 107 children. Glutathione peroxidase activities of the children were lower than activities observed in New Zealand adults, refelecting their lower blood Se concentrations.