Since 1974, the New Zealand Total Diet Study (NZTDS), initially coordinated by the then Chemistry Division of DSIR and now led by New Zealand Food Safety, has been our national survey for understanding what New Zealanders are exposed to from the foods they eat. 

Every 5 to 7 years, thousands of samples of commonly eaten foods are taken from regional centres over a year-long period, prepared as they would be consumed and tested for a range of chemicals. By combining laboratory results with information on what and how much people eat, the study estimates New Zealanders’ dietary exposure to agricultural compounds (mainly pesticides), environmental contaminants (such as heavy metals) and key nutrients. 

This long-running study has identified potential food safety risks, supported decision making, and continues to monitor changes in chemical exposure from foods. For example, the NZTDS showed that the amount of lead in our diet has fallen following the phaseout of leaded petrol and lead solder in canned foods. Since 1982, the NZTDS reported insufficient iodine intakes across all population groups. These findings supported introducing mandatory fortification of bread with iodised salt in 2009, and dietary intakes have improved in subsequent studies. 

The NZTDS continues to provide assurance on the safety of our food supply. Results of the 2024 NZTDS, focusing on infants and toddlers, are expected to be published later this year.