Turnlund's copper model, first published in 1994, was based on studies of healthy volunteers. It was the first-ever computerized model of how copper is metabolized in healthy people. The model has provided new support for what some scientists had suspected earlier, namely that copper most likely progresses though our bodies primarily in one-way paths, with little recycling. In their studies of molybdenum, Turnlund and coinvestigators have produced another computerized model similar to the copper one. We estimated that the minimum requirement for adults is about 25 micrograms a day.
People usually eat considerably more than that in a day's worth of ordinary meals.
The investigation was the first to provide an estimated minimum level for molybdenum in healthy volunteers. The level varies, however, according to the quantity of molybdenum in the soil where the crop was grown. In her magnesium research, Turnlund is now tackling the daunting task of determining an easy, reliable way to measure how much of this mineral we absorb from our food. In this venture, she's collaborating with the producers of Perrier, a premium bottled water. To find out, they need a good way to measure magnesium absorption.