The changing selenium status of New Zealand residents

The aim of this paper was to compile all the studies of selenium status carried out in Otago and in other areas of New Zealand in order to follow the history of selenium status in New Zealand residents over the last 20 years.

Since 1970 baseline blood samples have been collected from several groups of healthy adult subjects, either for the assessment of Se status or to determine baseline Se levels as part of a number of other studies. A comparison has been made of selenium concentrations recorded in recent published and unpublished studies with earlier studies by the Otago research group, and also those by other groups in New Zealand.

Otago and other New Zealand centres.

Blood selenium concentrations of Otago residents were consistently low from 1972 until 1988 at around 0.77 mumol/l, apart from a temporary increase in 1985, and then rose to reach 1.03 mumol/l in 1991 and 1.19 mumol/l in 1992-3. Blood selenium status reflected changes in the importation of Australian wheat. Correlations between selenium and glutathione peroxidase in whole blood and plasma were consistently high prior to 1989, but were no longer significant from 1990.

The lack of a correlation between selenium and glutathione peroxidase in bloods collected after 1990 indicates that at least for glutathione peroxidase, the selenium intake of New Zealanders is now close to that required for saturation. Whether this is sufficient to meet the requirements for other functional selenoproteins or for a possible cancer prevention effect remains to be determined.