Technical Abstract: In addition to cobalt (as vitamin B-12), copper, iodine, iron, selenium and zinc, there is a disparate group of 17 elements that have been suggested to be of nutritional importance for human health and well- being. These elements are manganese and molybdenum which have known essential functions but no unequivocally identified practical nutritional importance; boron and chromium which have apparent beneficial, if not essential, actions in humans, but no specifically identified biochemical roles; nickel and vanadium which have clearly identified biochemical roles in lower forms of life and an impressive number of reports describing deprivation signs in animals; arsenic and silicon for which there are reported deprivation signs for animals, and an arsenic-methylating enzyme has been identified and silicon has been found essential for some lower forms of life; fluorine and lithium which have beneficial pharmacologic actions, but rather limited evidence for essentiality; and finally, aluminum, bromine, cadmium, germanium, lead, rubidium, and tin which have some bits of credible evidence from animal models to suggest that they have at least positive effects under some situations. Thus, although differing guidance is appropriate for these elements, most need increased attention in this area because a new paradigm is emerging which acknowledges that the determination of nutritional importance should include consideration of total health effects of a substance, not just the ability to prevent deficiency pathology. Many of the 17 elements have identified or hypothesized actions that could help prevent some diseases associated with aging.