Shop products for Blue Green Algae 
What is it?
Blue-green algae, of which spirulina is a well-known example, is a group of 1,500 species of microscopic aquatic plants. The two most common species used for human consumption are Spirulina maxima and Spirulina platensis. Spirulina is particularly rich in protein and also contains carotenoids, vitamins, minerals, and essential fatty acids.1
Spirulina’s vitamin B12 content does not appear to be readily usable by people.2 Most health benefits to humans claimed for spirulina and other blue-green algae supplementation are supported by anecdotes rather than scientific research. Test tube and animal studies have demonstrated several properties of large amounts of spirulina or spirulina extracts, including antioxidant,3 antiviral,4 5 anticancer,6 7 8 9 anti-allergy,10 11 immune-enhancing,12 13 14 liver-protecting,15 16 17 blood vessel-relaxing,18 and blood lipid-lowering19 20 effects.
A small, controlled study found that overweight people taking 8.4 grams per day of spirulina lost an average of three pounds in four weeks compared with one and a half pounds when taking placebo, though this difference was not statistically significant and no effects on blood pressure or serum cholesterol were observed.21 A later, controlled trial found a small cholesterol-lowering effect when 4.2 grams of spirulina per day were taken for eight weeks, but serum triglycerides, blood pressure, and body weight were unchanged.22
Where is it found?
Blue-green algae grow in some lakes, particularly those rich in salts, in Central and South America, and Africa. They are also grown in outdoor tanks specifically to be harvested for nutritional supplements.
Blue-green algae have been used in connection with the following conditions (refer to the individual health concern for complete information):
| Rating | Health Concerns |
|---|---|
 |
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Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary
studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but
minimal or no scientific evidence. For a supplement, little scientific support and/or minimal
health benefit. | |
Who is likely to be deficient?
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.
How much is usually taken?
Blue-green algae can be taken as a powder or as flakes, capsules, or tablets. The typical manufacturer’s recommended intake is 2,000–3,000 mg per day divided throughout the day. However, typical amounts shown to have helpful properties in animal studies would be equivalent to 34 grams per day or more, for a 150-pound human.
Are there any side effects or interactions?
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,23 though noncontaminated blue-green algae have been identified.24 Another popular species of blue-green algae, Aphanizomenon flos-aquae, has been found to produce toxins.25 A few reports also describe allergic reactions to blue-green algae. Animal studies have found spirulina to be safe during pregnancy.26 27 28
There is one case report of a man who developed liver damage while taking spirulina.29 As he was also talking three prescription medications, it is not clear whether the spirulina caused or contributed to the liver injury.
At the time of writing, there were no well-known drug interactions with blue-green algae.
References
1. Dillon JC, Phuc AP, Dubacq JP. Nutritional value of the alga Spirulina. World Rev Nutr Diet 1995;77:32-46.
2. Dagnelie PC, van Staveren WA, van den Berg H. Vitamin B-12 from algae appears not to be bioavailable. Am J Clin Nutr 1991;53:695-7.
3. Miranda MS, Cintra RG, Barros SB, et al. Antioxidant activity of the microalga Spirulina maxima. Braz J Med Biol Res 1998;31:1075-9 [in Spanish].
4. Ayehunie S, Belay A, Baba TW, et al. Inhibition of HIV-1 replication by an aqueous extract of Spirulina platensis (Arthrospira platensis). J Acquir Immune Defic Syndr Hum Retrovirol 1998;18:7-12.
5. Hayashi K, Hayashi T, Kojima I. A natural sulfated polysaccharide, calcium spirulan, isolated from Spirulina platensis: in vitro and ex vivo evaluation of anti-herpes simplex virus and anti-human immunodeficiency virus activities. AIDS Res Hum Retroviruses 1996;12:1463-71.
6. Mishima T, Murata J, Toyoshima M, et al. Inhibition of tumor invasion and metastasis by calcium spirulan (Ca-SP), a novel sulfated polysaccharide derived from a blue-green alga, Spirulina platensis. Clin Exp Metastasis 1998;16:541-50.
7. Chen F, Zhang Q. Inhibitive effects of spirulina on aberrant crypts in colon induced by dimethylhydrazine. Chung Hua Yu Fang I Hsueh Tsa Chih 1995;29:13-7 [in Chinese].
8. Schwartz J, Shklar G, Reid S, Trickler D. Prevention of experimental oral cancer by extracts of Spirulina-Dunaliella algae. Nutr Cancer 1988;11:127-34.
9. Schwartz J, Shklar G. Regression of experimental hamster cancer by beta carotene and algae extracts. J Oral Maxillofac Surg 1987;45:510-5.
10. Kim HM, Lee EH, Cho HH, et al. Inhibitory effect of mast cell-mediated immediate-type allergic reactions in rats by spirulina. Biochem Pharmacol 1998;55:1071-6.
11. Yang HN, Lee EH, Kim HM. Spirulina inhibits anaphylactic reaction. Life Sci 1997;61:1237-44.
12. Qureshi MA, Garlich JD, Kidd MT. Dietary Spirulina platensis enhances humoral and cell-mediated immune functions in chickens. Immunopharmacol Immunotoxicol 1996;18:465-76.
13. Qureshi MA, Ali RA. Spirulina platensis exposure enhances macrophage phagocytic function in cats. Immunopharmacol Immunotoxicol 1996;18:457-63.
14. Hayashi O, Katoh T, Okuwaki Y. Enhancement of antibody production in mice by dietary Spirulina platensis. J Nutr Sci Vitaminol (Tokyo) 1994;40:431-41.
15. Torres-Duran PV, Miranda-Zamora R, Paredes-Carbajal MC, et al. Spirulina maxima prevents induction of fatty liver by carbon tetrachloride in the rat. Biochem Mol Biol Int 1998;44:787-93.
16. Vadiraja BB, Gaikwad NW, Madyastha KM. Hepatoprotective effect of C-phycocyanin: protection for carbon tetrachloride and R-(+)-pulegone-mediated hepatotoxicity in rats. Biochem Biophys Res Commun 1998;249:428-31.
17. Gonzalez de Rivera C, Miranda-Zamora R, Diaz-Zagoya JC, et al. Preventive effect of Spirulina maxima on the fatty liver induced by a fructose-rich diet in the rat, a preliminary report. Life Sci 1993;53:57-61.
18. Paredes-Carbajal MC, Torres-Duran PV, Diaz-Zagoya JC, et al. Effects of dietary Spirulina maxima on endothelium dependent vasomotor responses of rat aortic rings. Life Sci 1997;61:PL 211-9.
19. Iwata K, Inayama T, Kato T. Effects of Spirulina platensis on plasma lipoprotein lipase activity in fructose-induced hyperlipidemic rats. J Nutr Sci Vitaminol (Tokyo) 1990;36:165-71.
20. Gonzalez de Rivera C, Miranda-Zamora R, Diaz-Zagoya JC, et al. Preventive effect of Spirulina maxima on the fatty liver induced by a fructose-rich diet in the rat, a preliminary report. Life Sci 1993;53:57-61.
21. Becker EW, Jakober B, Luft D, et al. Clinical and biochemical evaluations of the alga Spirulina with regard to its application in the treatment of obesity. A double-blind crossover study. Nutr Rep Int 1986;33:565-73.
22. Nakaya N, Homma Y, Goto Y. Cholesterol lowering effect of Spirulina. Nutr Rep Int 1988;37:1329-37.
23. Johnson PE, Shubert LE. Accumulation of mercury and other elements by spirulina (cyanophyceae). Nutr Rep Int 1986;34:1063–70.
24. Slotton DG, Goldman CR, Franke A. Commercially grown spirulina found to contain low levels of mercury and lead. Nutr Rep Int 1989;40:1165–72.
25. Elder GH, Hunter PR, Codd GA. Hazardous freshwater cyanobacteria (blue-green algae). Lancet 1993;341:1519–20 [letter].
26. Salazar M, Chamorro GA, Salazar S, et al. Effect of Spirulina maxima consumption on reproduction and peri- and postnatal development in rats. Food Chem Toxicol 1996;34:353–9.
27. Kapoor R, Mehta U. Effect of supplementation of blue green alga (Spirulina) on outcome of pregnancy in rats. Plant Foods Hum Nutr 1993;43:29–35.
28. Chamorro G, Salazar M. Teratogenic study of Spirulina in mice. Arch Latinoam Nutr 1990;40:86–94 [in Spanish].
29. Iwasa M, Yamamoto M, Tanaka Y, et al. Spirulina-associated hepatotoxicity. Am J Gastroenterol 2002;97:3212–3. [Letter]
