Submitted to: Journal of Nutrition
Publication Type: Review Article
Publication Acceptance Date: September 10, 1996
Publication Date: N/A
Interpretive Summary: Although the importance of mineral elements in human nutrition is well established, tests for the routine assessment of mineral element status are generally lacking. Measurements of blood concentrations of minerals are insensitive to decreases in mineral status that are associated with disturbances in general health indicators. Therefore a new approach is needed to monitor subclinical signs of decreased mineral element status. A novel strategy is to examine alterations in physiological and psychological functions of humans in response to inadequate amounts of specific minerals in the diet. By using standardized stressors in concert with graded amounts of minerals in the diet, one has the opportunity to identify mineral-specific actions in dynamic biological function. We have used this experimental approach and found that inadequate dietary copper causes exaggerated blood pressure response during hand-grip exercise and sleep disturbances; low dietary iron impairs energy utilization in the cold and during exercise and resulted in decreased quality and quantity of sleep; decreased dietary zinc reduces body heat production, impairs the breakdown of ethanol and decreased the function of the brain to control manual tasks; and low calcium intake exacerbated the symptoms of, and increased mood disturbances, during the menstrual cycle. The further use of functional tests to evaluate adequacy of dietary mineral element intake has the potential to provide novel information on nutrient requirements to promote human health and to optimize biological function and performance.
Technical Abstract: One factor limiting efforts to determine human requirements for dietary intakes of mineral elements has been the unavailability of acceptable standards for evaluating the effects of marginal and mild deficiencies. Traditional approaches, such as growth, longevity, chemical balance and measurement of concentrations of minerals in plasma or serum and cellular components of the blood, have not been sensitive indicators of mineral nutriture. One alternative that has been shown to be responsive to graded dietary mineral intake is the evaluation of functional responses to specific challenges or stressors. Aberrant responses, either exaggerated or attenuated, to controlled stressors have been observed in a variety of physiological, psychological and immunological parameters when mineral intakes have been suboptimal, as compared to adequate, by conventional standards. In comparison to static biochemical approaches for assessment of mineral nutritional status, functional tests may be sensitive and responsive to alterations in mineral intake in adult humans. Dynamic functional measures complement static biochemical measures and reflect the net effect of deficiencies on integrated biological systems. Use of some of these types of dynamic evaluations of function may be a useful and productive approach for proposing mineral element intakes to optimize human health and biological function and performance.