Spirulina is a type of blue-green algae that is rich in protein, vitamins, minerals, and carotenoids, antioxidants that can help protect cells from damage. It contains nutrients, including B complex vitamins, beta-carotene, vitamin E, manganese, zinc, copper, iron, selenium, and gamma linolenic acid (an essential fatty acid).
Spirulina -- like any blue-green algae -- can be contaminated with toxic substances called microcystins. It can also absorb heavy metals from the water where it is grown. For these reasons, it is important to buy spirulina from a trusted brand.
Test tube and animal studies suggest spirulina may boost the immune system, help protect against allergic reactions, and have antiviral and anticancer properties. However, there is no proof that spirulina has these, or any, benefits in people. More research is needed.
Immune Support
A number of animal and test tube studies suggest that spirulina increases production of antibodies, infection-fighting proteins, and other cells that improve immunity and help ward off infection and chronic illnesses such as cancer. However, it has not been tested in people. In one clinical trial that involved humans, another type of blue-green algae called chlorella did not boost the immune response to flu vaccine.