Asian Journal of Biology

Cyanobacteria are increasingly presented as resource-efficient sources of protein, pigments and functional ingredients and as biological inputs that may improve crop production. This critical narrative review evaluates how far those claims are supported for sustainable food production, with emphasis on cultivated edible cyanobacteria, especially commercial Spirulina produced from Limnospira (Arthrospira) platensis, and on selected Nostoc foods. Peer-reviewed literature published from 1 January 2000 to 30 May 2026 was located through PubMed/MEDLINE, the Directory of Open Access Journals, ScienceOpen, FAO AGRIS and OpenAIRE Explore, supplemented by citation searching and verification of article and DOI records. Evidence was appraised for taxonomic precision, compositional representativeness, experimental scale, analytical validity, external validity and the transparency of life-cycle and techno-economic assumptions. Cyanobacterial biomass can supply concentrated protein, minerals, fatty acids and bioactive compounds, while phycocyanin has a distinctive role as a natural blue colourant. However, composition and digestibility vary by strain, cultivation conditions and processing, and many nutritional and food-function claims remain based on in vitro assays or laboratory prototypes. Low inclusion levels can improve the nutritional or technological properties of pasta, bakery and other foods, but colour, odour and flavour often limit acceptance at higher doses. Sustainability is not intrinsic to cyanobacterial production: mixing, temperature control, harvesting and drying can dominate energy demand and cost, and favourable outcomes depend on climate, scale, product form, co-product recovery and credible use of safe circular inputs. Market surveillance also demonstrates the need for source authentication and batch testing for cyanotoxins, metals, microorganisms, composition and allergens. Agricultural biostimulant and biofertiliser pathways are promising but still require stronger field-scale and economic validation. The review concludes that cyanobacteria can contribute to sustainable food systems when strain selection, food-grade process control, low-energy downstream operations, fit-for-purpose product design and transparent environmental accounting are integrated rather than treated as separate optimisation problems.