Is Spirulina safe in terms of heavy metals? A public health risk assessment

Spirulina is a microalga/cyanobacterium widely consumed as a dietary supplement due to its high nutrient content and health benefits. While Spirulina is recognized for its contribution to daily mineral intake (e.g., iron, manganese, magnesium, and potassium), its ability to bind heavy metals raises safety concerns, particularly for vulnerable age groups. This study analyzed eight commercial Spirulina supplements (powder and tablet forms) consumed in Türkiye for heavy metal and macro-mineral content using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The health risks were assessed across various age groups, including pregnant and breastfeeding women. Significant variability was found in heavy metal and mineral concentrations among the supplements, with one sample (S3) exceeding acceptable Hazard Index (HI) levels for all age groups except adults. Notably, Spirulina supplements generally did not exceed the established dietary reference values or Codex limits for heavy metals, except in certain younger age groups where potential non-carcinogenic risks were observed. The results emphasize the importance of determining safe consumption levels for Spirulina and other algae-based supplements to mitigate risks while maximizing their nutritional benefits. Additionally, the findings highlight the need for public health guidelines to standardize Spirulina’s daily intake and labeling practices.