Selenium status of Christchurch infants and the effect of diet

New Zealanders, because of a soil deficiency, have a low intake of selenium. To determine the impact of this on the infant population in Christchurch.

we have measured red cell and plasma selenium and the selenoenzyme, glutathione peroxidase, in 70 infants less than 12 months old and related these to age and diet.

the infant population as a whole had mean plasma levels of selenium and glutathione peroxidase of 33 micrograms/L and 97 U/L compared with adult values of 74 micrograms/L and 150 U/L. Infant red cell levels of 0.30 mu g selenium and 9.0 U glutathione peroxidase per g haemoglobin were similar to those in adults. The selenium status of most breast fed infants after birth remained similar to that of cord blood. Mean plasma selenium and glutathione peroxidase levels in formula fed infants were about half those of breast fed infants, and their red cell selenium was also significantly lower. These did not increase until solids were introduced into the diet. The status of the infants reflected their diet, with the concentration of selenium in formulae being 3.9-5.2 micrograms/mL compared with a mean of 13.4 micrograms/mL in breast milk.

since infants in more replete selenium areas show a gradual rise in blood selenium parameters after birth, this study suggests that formula fed and some breast fed infants in Christchurch receive an inadequate selenium intake. Consideration should be given to supplementing infant formulae and perhaps also the diet of pregnant and/or breast feeding mothers.