Australian brown seaweeds as a source of essential dietary minerals

Abstract Interest in the potential to both farm and wild-harvest seaweeds in Australia is rapidly increasing. Seaweeds are rich sources of dietary trace minerals and essential elements that are often not found in terrestrial edible plant foods. Due to the high affinity for mineral and contaminant accumulation by seaweeds, it is important to conduct in depth studies on seaweeds that have edible potential and are being considered for sustainable aquaculture or wild harvest. This study screened six Australian fucoid and laminarian brown seaweeds for their dietary mineral composition. Spatial replicate samples of each species were collected from three ‘clean’ Victorian sites (classified based on their proximity to urbanisation and potential pollution sources) and processed with methods consistent for human consumption. Dried and ground samples were analysed by ICP-MS and concentrations of 12 key dietary minerals were compared amongst species. The overall dietary mineral composition differed significantly amongst all species, except between two species in the Sargassaceae; but concentrations of individual dietary minerals varied amongst species in complex ways. Results are discussed in the context of the potential health benefits from consuming the species studied in realistic quantities (e.g. 10 g·d-1 dried seaweed) as part of balanced omnivorous and plant-based diets. This study demonstrated high levels of dietary minerals essential for optimal human health in the Australian brown seaweeds investigated, but further investigation into ways to reduce iodine content in some species may be required to maximise health benefits from regular consumption.