Screen for cyanotoxins in cyanobacteria based food supplements on the Belgian market

During the last years, the financial turnover of the non-registered consumer health market and the share of food supplements in this market has grown at a steady pace1. This growth implies an increased exposure of the public to these products and their ingredients. Some ingredients, mainly from natural sources, have beneficial effects but might exert adverse effects due to the presence of non-intentional compounds, like natural toxins. Food supplements produced by microalgae or cyanobacteria could be one of these examples. Within this group of products, three organisms are responsible for the production. First of all, the green algae called Chlorella vulgaris, for which commercialization started post-WW2. Second, the cyanobacterium Aphanizomenon flos-aquae, which is known to form massive blooms in Klamath Lake in Oregon US. Third, we have Arthrospira sp., better known under its trade name “spirulina”. This organism has been harvested from lakes in Africa and South America for a long time. Retailers advertise these food supplements as protein-rich food sources with additional health benefits. However, the scientific community devoted to cyanobacteria has expressed doubts surrounding the safety of some of the supplements available on the market. Research has shown that some cyanobacterial species can produce toxins harmful to humans. These toxins are commonly detected in blooms of cyanobacteria in lakes all over the world. In Western Europe, microcystin is frequently detected. Microcystin congeners (MC’s) are hepatotoxic and cause nausea, vomiting and, in severe cases, liver damage when ingested. Although the most species used to produce the food supplements (except Aphanizomenon) should not produce these toxins themselves, published data suggest that there could be contamination of the products by toxin-producing cyanobacteria. Production steps vulnerable for contamination are cultivation and processing of the organisms (cyanobacteria). MATERIAL AND METHODS To acquire initial data of the presence of microcystins and the related nodularin in food supplements, we optimized and validated an analytical method capable of quantification of eight microcystin congeners and nodularin based on the protocol by Turner et al., 20182. With this method, we analyzed 40 samples from the Belgium market. The samples were bought from the major retailers in Belgium. RESULTS AND CONCLUSION The results show MC’s in several products. Some of them were above the guideline values suggested by the WHO3, which poses a possible risk for public health. To better assess this risk, exposure studies should be executed to evaluate the consumption of these products in Belgium. The consumption data of food supplements are not readily available and include several assumptions, which is another hurdle for this research