Even without modern science, the Mexica could recognise the nutrient density that has made spirulina such a favourite today. It boasts about 60-70% protein by weight and has essential amino acids and many vitamins and minerals, especially iron, manganese and B vitamins, according to the Encyclopedia of Dietary Supplements. It's so healthy and relatively easy to grow, in fact, that experts think it could be a potential food source for future Mars colonies.
