Food system-based approaches to improving micronutrient nutrition: the case for selenium.

Micronutrient deficiencies affect nearly half the world's population, impairing child development, reducing work productivity, and increasing mortality and morbidity rates by affecting both infectious and chronic diseases. To feed a growing world, it will be necessary to consider agriculture in the broad context of a food system as an instrument of public health and, thus, to address nutrient balance while also seeking sustainability. Such efforts would include increasing cropping system diversity, enhancing micronutrient outputs and promoting environmental sustainability. Example of this approach are presented for the essential trace element selenium (Se), which at high intakes can reduce cancer risks but is deficient in many parts of the world. Food systems-based approaches are discussed for preventing Se deficiency by enhancing intakes of any of several biologically available forms of Se, and for reducing cancer risk by enhancing intakes of forms of the element that support anti-tumorigenic Se-metabolites.