The metalloid selenium (Se) is ubiquitous in soils, but exists mainly in insoluble forms. Consequently, it is often supplied by plants to animals and humans at levels too low for optimum health. Se deficiency and sub-optimality are manifested in populations as increased rates of thyroid dysfunction, cancer, severe viral diseases, cardiovascular disease, and various inflammatory conditions. Se deficiency probably affects at least a billion people. Optimal cancer protection appears to require a supra-nutritional Se intake, and involves several mechanisms, which include promotion of apoptosis, and inhibition of neo-angiogenesis. In some regions Se is declining in the food chain, and new strategies to increase its intake are required. Se levels in healthy Australians are generally above the estimated global average but below an estimated optimal intake. Increasing the Se content of wheat, which supplies around half the dietary Se of most Australians, represents a food systems approach that would increase population intake, with likely improvement in public health. The strategy that shows most promise to achieve this is biofortification of wheat with selenate. Before recommending large-scale fortification of the food supply with Se, it will be necessary to await the results of current intervention studies.
Keywords: selenium, biofortification, wheat, disease prevention