Spirulina has shown some indication of having antiviral effects in preliminary in vitro and animal studies. There is also evidence of a preliminary nature that it might favorably affect some immune functions and have some hepatoprotective capability.
Spirulina is a genus of the phylum Cyanobacteria. Cyanobacteria are classified as either blue-green algae or as blue-green bacteria. Spirulina is a popular food supplement in Japan and is marketed as a nutritional supplement in the United States.
It has been consumed for thousands of years by Mexican (Aztecs, Mayans), African, and Asian peoples. There are several species of spirulina. The ones most commonly used in nutritional supplements are Spirulina platensis (also called Arthrospira platensis) and Spirulina maxima. Spirulina is a rich source of protein. It also contains chlorophyll, carotenoids, minerals, gamma-linolenic acid (GLA) and some unique pigments. These pigments, called phycobilins, include phycocyanin and allophycocyanin. The pigments give spirulina their bluish tinge. Phycobilins are similar in structure to bile pigments such as bilirubin. In the spirulina cell, phycobilins are attached to proteins; the phycobilin-protein complex is called phycobiliprotein. Spirulina is considered a complete protein, because half of it consists of amino acids — the building blocks of protein. It is also a rich source of other nutrients including B complex vitamins, beta-carotene, vitamin E, carotenoids, manganese, zinc, copper, iron, selenium, and gamma linolenic acid (an essential fatty acid). The iron level in spirulina is equivalent to that contained in beef. Because of its apparent ability to stimulate the immune system, spirulina may have antiviral and anticancer effects. Test tube and animal studies suggest that spirulina may also help protect harmful allergic reaction .