Does green mean good? Evaluating the safety of microalgae dietary and protein supplements

Recent natural health food trends have seen a wide range of products promoted with a myriad of health claims. This has led to the rise of the green smoothie and dietary supplements, many of which contain microalgae – a broad category of photosynthetic microorganisms including spirulina (common name for Arthrospira platensis and A. maxima). Microalgae have been used as food items since the 1960 s in Japan and are currently marketed as a “Super Food”. Worldwide, the market for microalgae was valued at ≈ $608 million US dollars in 2015 with a 5%-7% increase in production to an estimated 27,552 tons with about $1.1 billion US dollars by 2024. This huge market is driven by the potential of the crop in biofuels, omega-3 fatty acids, metal chelators and other products. Microalgae contain a high percentage of protein and bioactive peptides as well as phycobiliproteins and carotenoids. The objective of this study was to determine whether microalgae supplements contain the neurotoxin N-β-methylamino-L-alanine (BMAA) or its isomers N-(2-aminoethyl)glycine (AEG) and 2,4-diaminobutyric acid (DAB). BMAA was detected in 4 out of 5 supplements containing spirulina at a maximum concentration of 0.74 µg/g using the AOAC validated method. AEG and DAB were detected in all 5 samples at a maximum concentration of 6.48 µg/g and 107 µg/g respectively. Subsequent studies including spirulina products from Hawaii, China and the United States demonstrated that BMAA, AEG and DAB were present in all samples tested at a maximum concentration of 0.32 µg/g, 2.81 µg/g and 43.5 respectively. These studies demonstrate the need for strict quality control of microalgae food supplements as well as more clinical trials to evaluate their health effects before they can safely be brought to the market.