Nutritional Supplement
Blue-Green Algae (Spirulina)
Possible Deficiencies
As it is not an essential nutrient, blue-green algae is not associated with a deficiency state. However, people who do not consume several servings of vegetables per day could benefit from the carotenoids and other nutrients in blue-green algae. Since it is a complete protein, it can be used in place of some of the protein in a healthy diet. However, very large amounts are required to provide significant quantities of these nutrients from blue-green algae.
Side Effects
Few side effects have been reported from the ingestion of blue-green algae. However, as blue-green algae can accumulate heavy metals from contaminated water, consuming blue-green algae could increase the body’s load of lead, mercury, and cadmium,7 though noncontaminated blue-green algae have been identified.8 Another popular species of blue-green algae, Aphanizomenon flos-aquae, has been found to produce toxins.9 A few reports also describe allergic reactions to blue-green algae. Animal studies have found spirulina to be safe during pregnancy.10,11,12
There is one case report of a man who developed liver damage while taking spirulina.13 As he was also talking three prescription medications, it is not clear whether the spirulina caused or contributed to the liver injury.