Spirulina powder, coloured scanning electron micrograph (SEM). Spirulina cyanobacteria is a blue-green algae. It is non-toxic and is a nutrient dense food source that is often consumed as a powder. There are many potential health benefits associated with the regular consumption of spirulina which, along with many others, include decreased blood glucose levels for diabetes patients, the possibility of reducing the build up of plaque on arterial walls (anti-atherogenic) and reducing anaemia. However, further research needs to be undertaken before health claims relating to spirulina can be confirmed regarding the efficacy of this algae in a large population. Magnification: x800 when printed at 10cm wide.