Seaweed aquaculture as a sustainable source of functional foods

• Seaweed presents opportunities as a sustainable, nutritious novel food. • Seaweed can help address food security and nutritional deficiencies worldwide. • Seaweed aquaculture has socio-economic and cultural benefits for local populations. • Production may be carbon-neutral and can positively affect neighbouring ecosystems. • Further research into toxicant bioaccumulation and mechanistic studies are needed. Seaweed cultivation is the fastest-growing aquaculture sector. However, despite the crucial need for new food sources, human consumption of edible macroalgae as food remains limited in most countries. In this interdisciplinary review, we examine the potential of seaweed aquaculture to provide nutritious, functional foods as an industry focused on social, economic, and environmental sustainability. Seaweeds are excellent sources of proteins and fibres, constituting up to 35 and 66 % dry weight, respectively. Some species are particularly rich in vitamins A and B12, and their mineral contents far exceed those of terrestrial plants. Various nutraceutical effects, linked to compounds such as short-sequence peptides, pigments, and polysaccharides, have also been documented. The mineral content also raises toxicity concerns, and the variability and bioaccessibility of nutrients and bioactive compounds need further research to ensure product quality. Seaweeds are present in most coastal environments, and their cultivation is a low-resource, widely accessible activity. It can provide income, socio-economic status, and other ecosystem services to local populations, although issues with fair distribution of benefits persist. Finally, establishing cultivation areas may help protect local ecosystems and can provide low-carbon foodstuffs with minimal climate impact. Nevertheless, many challenges remain to the widespread adoption of seaweed aquaculture. Seaweed research must modernise and embrace mechanistic studies to provide better solutions to cultivation challenges and expand beyond the few currently cultivated species to suit regional needs. Local stakeholders should be included in decision-making and prioritised in socio-economic planning, and wild ecosystems preserved to truly harness the sustainable potential of seaweed cultivation.