Bottom Line: Blue-green algae may contain nutrients and vitamins, but it is NOT an effective treatment for cancer, HIV, attention deficit hyperactivity disorder (ADHD), or other serious medical conditions.
Scientists do not know how blue-green algae supplements might work, since limited research has been performed. Blue-green algae are a natural source of protein and vitamins, which might contribute to alleviation of fatigue. Blue-green algae products usually contain either AFA-algae (Aphanizomenon flos aquae) or Spirulina species, or both. Both may have biological activities. In laboratory experiments, calcium spirulan, an extract from Spirulina, inhibits the replication of HIV virus, herpes simplex virus, cytomegalovirus, and influenza virus in the test tube, but it is not known whether any of these anti-viral effects would occur in the human body. Other studies showed that spirulina protected lab animals from genetic mutations caused by chemicals and radiation, but again, it is unclear whether these effects happen in humans. In healthy humans, AFA-algae appear to increase blood levels of natural killer cells (a type of immune cell). AFA-algae also show anti-viral and anti-mutation activity in the laboratory.
Spirulina algae also contain high levels of gamma-linolenic acid (GLA), an essential fatty acid that is often able to prevent the accumulation of cholesterol in the body.
As an appetite suppressant No scientific evidence supports this use.
To treat ADHD (attention deficit hyperactivity disorder) No scientific evidence supports this use.
To prevent and treat cancer Laboratory studies show that blue-green algae may help protect against DNA mutations, but it is unknown whether this effect occurs in humans. One clinical trial supported the use of blue-green algae for prevention of oral cancer in tobacco chewers. There is no evidence that blue-green algae can treat cancer.
To prevent and treat fatigue No scientific evidence supports this use.
To treat HIV and AIDS Blue-green algae show anti-viral activity in the laboratory, but it is unknown whether this effect occurs in humans. There is no proof from clinical trials that blue-green algae can treat HIV and AIDS.
To stimulate the immune system One study in healthy humans showed that AFA-algae increased blood levels of natural killer cells (immune cells). There is no evidence that such effects help the body fight infections or maintain health.
To treat oral leukoplakia (a pre-cancerous condition characterized by thick white patches on the oral mucosa and tongue) One clinical trial supported the use of blue-green algae for prevention of oral cancer in tobacco chewers.
To treat viral infections Blue-green algae show anti-viral activity in the laboratory, but there is no proof from clinical trials that it can treat infections in humans.
Oral leukoplakia Researchers in India conducted a randomized, controlled trial to measure the effects of a blue-green algae supplement on the progression of oral leukoplakia, an often pre-cancerous condition of the mouth, in pan tobacco chewers. For twelve months, 45 patients were given 1 gram of Spirulina fusiformis per day while 43 patients were given a placebo pill. Complete regression of oral leukoplakia was seen in 20 of the patients taking Spirulina, but only three patients taking the placebo. Although this suggests that blue-green algae might work as chemoprevention for oral cancer, these findings might not apply in the long-term or to other types of patients (e.g., non-tobacco chewers).
Although it is uncommon, the algae used in this product may be contaminated with several toxins from the Microcystis species of algae. For example, anatoxin and saxitoxin are toxic to the nervous system, causing serious side effects like paralysis of the respiratory system. Microcystins are algal proteins that can cause liver and kidney damage. Any product you buy should be certified free of these Microcystis toxins.
This product is regulated by the F.D.A. as a dietary supplement. Unlike approved drugs, supplements are not required to be manufactured under specific standardized conditions. This product may not contain the labeled amount or may be contaminated. In addition, it may not have been tested for safety or effectiveness.
In rare cases, cyanotoxin (e.g. anatoxin, saxitoxin, microcystins) contamination of this product may cause liver damage, kidney failure, neurological damage, seizures, respiratory arrest, acute pancreatitis, and damage to the muscles of the heart.
Blue-green algae are used a source of food in parts of the world. Consumption of this product appears to be relatively safe, as long as it is not contaminated with Microcystin species.
Blue-green algae are primitive autotrophic prokaryotes (aka Cyanobacteria). Spirulina species are cultured in alkaline fresh water while Aphanizomenon flos aquae (AFA) is naturally grown and harvested from Upper Klamath Lake, Oregon, USA. Blue-green algae products frequently contain one or both of these strains of algae. Patients take blue-green algae supplements to prevent and treat cancer and viral infections, and for weight loss. A cholesterol-lowering effect was found in patients with nephrotic syndrome induced hyperlipidemia. Blue-green algae are used a source of food in parts of the world. Although no human clinical data support its use for any of the proposed claims, studies suggested spirulina has chemoprotective and radioprotective effects in animals. Blue-green algae may be contaminated by strains of algae (e.g. microcystin species) that are toxic. Adverse effects are uncommon except when products are contaminated; contaminant toxins can cause hepatotoxicity, renal failure, and neurotoxicity. To date, there are no known drug interactions. Supplementation with blue-green algae provides protein and small amounts of vitamins and minerals, but no research supports their value.
The mechanism of action is unknown. The protein and vitamin content may contribute to any alleviation of fatigue. Calcium spirulan, a polysaccharide extract from Spirulina platensis, demonstrates inhibition of HIV-1 viral replication via possible binding and disruption of CD4-gp120 interaction in vitro, although the clinical significance of this is unknown. In vitro, calcium spirulan also inhibits replication of herpes simplex I, cytomegalovirus, and influenza. Studies performed in healthy humans suggest that AFA-algae increase the level of circulating natural killer cells. In vitro studies also suggest that AFA-algae has antiviral and antimutagenic activity. Other studies suggested spirulina has chemoprotective and radioprotective effects in animals through the stimulation of the hemopoietic system. Although uncommon, several toxins from Microcystis species of algae may contaminate AFA-algae and Spirulina algae blooms. Anatoxin can cause paralysis of respiratory muscles due to irreversible binding and sustained action of the nicotinic acetylcholine receptor. Saxitoxin contamination is thought to block nerve cell neuronal transmission due to binding to voltage-gated sodium channels. Microcystins are cyclic heptapeptides that induce hepatotoxicity. (1)(2)(3)(4)(5)(6)(7)(8)
Mathew B, et al. Evaluation of chemoprevention of oral cancer with Spirulina fusiformis. Nutr Cancer 1995;24:197-202. A prospective, randomized, double-blind evaluation of blue-green algae supplementation in patients with homogenous and nonhomogenous oral leukoplakia. Patients were pan tobacco chewers recruited from Kerala, India. Following 12-months of supplementation with 1 gram per day Spirulina fusiformis (n=45) or placebo (n=43), conversion of oral leukoplakia lesions was increased for the active group. However, conversion of nonhomogenous lesions was similar between active and placebo groups, 1 and 2 cases respectively. Although the results suggest blue-green algae supplementation may be efficacious as chemoprevention for oral cancer, the long-term efficacy is unknown and extrapolations to other populations may not be appropriate.
Foster S, Tyler VE. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies 4th ed. New York: Haworth Herbal Press; 1999.
Ziegler R. Aphanizomenon flow-Aquae (AFA-Algae). A food supplement with dubious health claims. Meeting of the Swiss Study Group for Complementary and Alternative Methods in Cancer. Weiskirchen (Switzerland): November 9, 2001.
