Intake of food supplements based on algae or cyanobacteria may pose a health risk due to elevated concentrations of arsenic species.

Despite the health benefits of food supplements (FS) based on algae or cyanobacteria, the elevated arsenic (As) concentrations in these FS may raise a health concern. In the present study 33 FS containing algae or cyanobacteria were collected and As (species) were analysed to estimate consumer exposure. Based on hazard and exposure data, potential risks were evaluated using inorganic arsenic (As) and the potentially toxic As fraction (As minus arsenobetaine (AB)). As concentrations were in the range 0.053-57 mg/kg with highest concentrations in FS containing brown algae. As concentrations were in the range <0.02-4.7 mg kg. A large part of As in FS containing algae or cyanobacteria was identified as potentially toxic AsSugars species. Negligible amounts of AB were detected. According to a tentative risk evaluation, the intake of As related to all FS collected was of no health concern for the general population. In 8 out of 33 of the analysed FS, however, the As concentration was of concern for population groups with increased cancer risks. If all As species except the non-toxic AB were taken into consideration, only 26 out of 33 of the FS showed 'no concern' for the general population, while for the other 7 FS a potential health risk was identified. This study indicates the need to obtain more data on toxicity of AsSugars and to develop limits for As (species) in FS.