Commercial Edible Seaweeds: Characterization by Mineral Content and Fatty Acid Composition

In recent years, seaweeds have attracted increasing scientific and commercial interest thanks to their protein, lipid and mineral content, and the presence of bioactive compounds that can have a positive impact on health. In light of this, seaweed is an innovative plant food source. This study characterizes commercial edible seaweeds (dulse, wakame, kombu, arame, nori, spirulina), evaluating their mineral composition, with particular attention to toxic or potentially toxic elements, and their fatty acid profile. The results revealed significant differences between species, which are probably related to taxonomic and environmental factors. Brown algae exhibited the highest levels of macroelements, particularly K and Na, which is consistent with their alginate-rich cell walls. Other species exhibited significant concentrations of Fe and Zn, while Pb and Hg remained below regulatory limits. However, nearly all samples exceeded the recommended limits of 0.5 mg/kg for Cd and 3 mg/kg for total As, as defined by the Centre d'Étude et de Valorisation des Algues (CEVA). Additionally, kombu samples had an extremely high iodine content, exceeding the upper CEVA-recommended limit of 2000 mg/kg. These values, therefore, require targeted risk assessments and consumer guidance. The fatty acid profile also appeared to vary by taxa. Red algae, especially nori, were rich in EPA, while brown species showed heterogeneous distributions of SFA, MUFA, and PUFA. Spirulina displayed a distinctive SFA- and n-6 PUFA-rich profile. Overall, the results confirm the need for careful management of iodine, Cd and As levels to ensure that these seaweeds can be used safely as food supplements and to promote their use in innovative food products.