Why and how to use radioisotopes in human nutrition research.

Tracer methodology using radioisotopes in human nutrition research has been the object of unjustified limitations in its use. These limitations have encumbered research studies where micronutrient and macronutrient deficiencies are prevalent. Stable isotope methodologies are expensive, including the cost of the isotopes, equipment and its maintenance, and are often fraught with serious pitfalls. We have been developing safe radioisotopic methods to study the metabolism of micronutrients, especially iron and zinc in the developing world. These should allow scientists everywhere to conduct their own research without having to depend on facilities and laboratories in the industrial world, and thus enhance productive collaborative research. All radioisotopic research must be subjected to strict safety criteria, based on scientific evidence of risk, but should not be hampered by unscientific fears. Examples on the use of radio and stable isotopes to study iron and zinc absorptions are given including the radiation exposure and risk calculations.