The potential of inorganic mass spectrometry in mineral and trace element nutrition research.

Over the past two decades, new applications of inorganic mass spectrometry have been made possible by the use of stable isotopes as tracers in studies of mineral and trace element metabolism in man. Stable isotope techniques and radioisotope methods are the only reliable tools available for determination of the absorption, retention, or utilization of a nutrient by the human body. Recent developments in inorganic mass spectrometry might open new perspectives as progress in this field of research depends mainly on improving existing stable isotope techniques and on developing novel concepts. By improving precision in isotope analysis, isotope doses in experiments on man can be reduced to physiologically more meaningful levels. This will also enable reduction of the (often substantial) costs of isotopically labeling a nutrient in a test meal. Improvements in the mass spectrometric sensitivity will enable the development of new tracer techniques that have the potential to provide the information required by: 1. governmental institutions for designing food fortification programs; 2. the food industry for developing nutrient-fortified food products; and 3. public health authorities for establishing reliable dietary recommendations for intake of inorganic nutrients. In this context the current scope and limitations of thermal ionization mass spectrometry, inductively coupled mass spectrometry, accelerator mass spectrometry, and resonance ionization mass spectrometry are evaluated. Iron isotopic variations in the human body are discussed as a possible source of bias that might be a future biological limit to stable isotope-dose reduction in experiments on iron metabolism in man.