Why is IAEA measuring dietary intakes of trace elements?

• Essential trace elements such as iron, iodine, selenium and zinc are involved in numerous biochemical functions, and deficiencies of these elements are associated with serious diseases, particularly in developing countries; intakes of these elements are entirely through the diet..

• Human exposure to toxic elements such as mercury, cadmium, lead and arsenic is mainly through the diet; developing countries are especially at risk.

• Desirable levels of dietary intake have been defined by WHO, FAO and IAEA expert groups; comparison of actual intake with these guidelines reveals whether populations are at risk of deficiency or toxicity.

The IAEA's role in dietary intake studies

The IAEA has been encouraging some nuclear laboratories in developing countries to establish collaborative research programmes with their national institutes of nutrition on projects that can take advantage of the high specificity and sensitivity of nuclear analytical techniques. Studies of trace elements in foods and diets have turned out to be among the most useful of these applications.

Nuclear and related analytical techniques (such as neutron activation analysis ICP-MS and XRF) provide high sensitivity and specificity for the determination of many of these elements infoodstuffs and diets. Examples of the IAEA's support for research on dietary intakes of trace elements include:

• studies of dietary intakes of 23 minor and trace elements recently completed in 16 countries (Australia, Belarus, Canada, China, Finland, Iran, Italy, Japan, Portugal, Russia, Spain, Sudan, Thailand, Turkey, Ukraine, USA);

• additional on-going studies in 10 Asian countries (Bangladesh, China, India, Indonesia, Japan, Korea, Malaysia, Pakistan, Philippines and Vietnam);

• studies of toxic elements in foods and diets in 12 countries (Argentina) Australia, Bangladesh, Brazil, China, India, Indonesia, Jamaica, Japan, Malaysia, Pakistan and Thailand);

• studies of dietary exposure to mercury and methyl mercury in 9 countries (Brazil, Chile, China, Czech Republic, India, Italy, Malaysia, Slovenia and Vietnam) using human hair as a biomonitor;

• evaluation of dietary intake data for a WHO/FAD/IAEA Expert Committee which has developed new guidelines on desirable levels of dieter intake of essential trace elements;

• development of several new analytical reference materials or use in the determination of trace elements in foods and diets; and

• creation of the world's most extensive database on certified analytical reference materials for trace elements, radionuclides and microcontaminants (used in food analysis laboratories for checking accuracy).