Spirulina (dietary supplement)

Spirulina is the common name for human and animal food supplements produced primarily from two species of cyanobacteria (also known as blue-green algae): Arthrospira platensis, and Arthrospira maxima. These and other Arthrospira species were once classified in the genus Spirulina. There is no agreement that they are distinct genera, and that the food species belong to Arthrospira; nonetheless, the older term Spirulina remains the popular name. Spirulina is cultivated around the world, and is used as a human dietary supplement as well as a whole food and is available in tablet, flake, and powder form. It is also used as a feed supplement in the aquaculture, aquarium, and poultry industries.^[1]

Biology

Spirulina are free-floating filamentous cyanobacteria characterized by cylindrical, multicellular trichomes in an open left-hand helix. Spirulina occurs naturally in tropical and subtropical lakes with high pH and high concentrations of carbonate and bicarbonate. A. platensis occurs in Africa, Asia and South America, whereas A. maxima is confined to Central America.^[1]

History

Spirulina is believed to have been a food source for the Aztecs and other Mesoamericans until the 16th-century; its harvesting from Lake Texcoco and subsequent sale as cakes is described by one of Cortés' soldiers.^[2] The Aztecs called it Teocuitlatl, meaning stone's excrement. Spirulina was found in abundance at the lake by French researchers in the 1960s, but there is no reference to its use there as a daily food source after the 16th century. The first large-scale Spirulina production plant, run by Sosa Texcoco, was established there in the early 1970s.^[1]

Leo Szilard postulated the development of algae-based food supplements (which he called "Amruss") in his 1961 short story, The Voice of the Dolphins.

Spirulina may have an even longer history in Chad, as far back as the 9th century Kanem Empire. It is still in daily use today, dried into cakes called Dihé, which are used to make broths for meals, and also sold in markets. The Spirulina is harvested from small lakes and ponds around Lake Chad.^[3]

Cultivation

Nutrients and other chemicals

Protein

Spirulina contains an unusually high amount of protein, between 55% and 77% by dry weight, depending upon the source. It is a complete protein,^{citation needed} containing all essential amino acids, though with reduced amounts of methionine, cysteine, and lysine when compared to the proteins of meat, eggs, and milk. It is, however, superior to typical plant protein, such as that from legumes.^[4]^[5]

Essential fatty acids

Vitamins

Spirulina contains vitamin B1 (thiamine), B2 (riboflavin), B3 (nicotinamide), B6 (pyridoxine), B9 (folic acid), vitamin C, vitamin D, and vitamin E.^[5]^[6] The bioavailability of vitamin B12 in Spirulina is in dispute. Several biological assays have been used to test for the presence of vitamin B12.^[7] The most popular is the US Pharmacopeia method using the Lactobacillus leichmannii assay. Studies using this method have shown Spirulina to be a minimal source of bioavailable vitamin B12.^[8] However, this assay does not differentiate between true B12 (cobalamin) and similar compounds (corrinoids) that cannot be used in human metabolism. Cyanotech, a grower of spirulina, claims to have done a more recent assay, which has shown Spirulina to be a significant source of cobalamin. However the assay is not published for scientific review and so the existence of this assay is in doubt.^[9] The American Dietetic Association and Dietitians of Canada in their position paper on vegetarian diets state that spirulina can not be counted on as a reliable source of active vitamin B12.^[10]

Minerals

Photosynthetic pigments

Evidence of health and healing effects

Despite existing research supporting Spirulina's health and healing properties, detractors claim that these are frequently overstated by Spirulina advocates. Conversely, Spirulina advocates have accused health food detractors of dismissing all such claims without acknowledging this research. Two online publications exemplify these opposing positions, respectively: Wellness Letter on Blue Green Algae, and Superfoods For Optimum Health: Chlorella and Spirulina. Many positive claims are based on research done on individual nutrients that Spirulina contains, such as GLA, various antioxidants, etc., rather than on direct research using Spirulina. What follows is research on the health and healing effects of Spirulina. In vitro research (e.g., studying cells in a petri dish) may suggest the possibility of similar results in humans but, due to the drastically different conditions of the research, provides only hints at the potential for human effects. Animal research can also provide evidence of potential human effects. Human research focuses on actual effects in humans - however, the validity and reliability of the research depends on the design of the study. The strongest evidence comes from well designed and controlled clinical trials, which are one type of human research study.

In vitro research

Animal research

Human Research

A 2007 study ^[19] found that 36 volunteers taking 4.5 grams of spirulina per day, over a six week period, exhibited significant changes in cholesterol and blood pressure: (1) lowered total cholesterol; (2) increased HDL cholesterol; (3) lowered triglycerides; and (4) lowered systolic and diastolic blood pressure. However, as this study did not contain a control group, we can not be confident that the changes observed are due totally - or even partially - to the effects of the Spirulina Maxima as opposed to other confounding variables (i.e., history effects, maturation effects, demand characteristics).

Advocates

The United Nations World Food Cenference in 1974 lauded Spirulina as the 'best food for the future.' Recognising the inherent potential of Spirulina in the sustainable development agenda, several Member States of the United Nations came together to form an intergovernmental organization by the name of the Intergovernmental Institution for the Use of Micro-algae Spirulina Against Malnutrition.^[20] IIMSAM aspires to build a consensus to make Spirulina a key driver to eradicate malnutrition, achieve food security and bridge the health divide throughout the world.

References

^ ^a ^b ^c ^d ^e Vonshak, A. (ed.). Spirulina platensis (Arthrospira): Physiology, Cell-biology and Biotechnology. London: Taylor & Francis, 1997.
^ Diaz Del Castillo, B. The Discovery and Conquest of Mexico, 1517-1521. London: Routledge, 1928, p. 300.
^ Abdulqader, G., Barsanti, L., Tredici, M. "Harvest of Arthrospira platensis from Lake Kossorom (Chad) and its household usage among the Kanembu." Journal of Applied Phychology. 12: 493-498. 2000.
^ Ciferri, O. "Spirulina, the Edible Microorganism." Microbiological Reviews. 47, 4, Dec. 1983.
^ ^a ^b ^c ^d Babadzhanov, A.S., et al. "Chemical Composition of Spirulina Platensis Cultivated in Uzbekistan." Chemistry of Natural Compounds. 40, 3, 2004.
^ ^a ^b ^c Tokusoglu, O., Unal, M.K. "Biomass Nutrient Profiles of Three Microalgae: Spirulina platensis, Chlorella vulgaris, and Isochrisis galbana." Journal of Food Science. 68, 4, 2003.
^ Variations in the Growth Response of Four Different Vitamin B12 Assay Microorganisms to the Same Tissue and Standard Preparations. Elizabeth A. Cook and Lillian N. Ellis. Appl Microbiol. 1968 December; 16(12): 1831–1840.
^ Watanabe, F. et al. "Characterization and bioavailability of vitamin B12-compounds from edible algae." Journal of nutritional science and vitaminology, Oct. 2002, 48 (5):325-331.
^ Spirulina Pacifica as a Source of Cobalamin Vitamin B-12. Jan. 1999.
^ Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets
^ Ayehunie, S. et al. "Inhibition of HIV-1 Replication by an Aqueous Extract of Spirulina platensis (Arthrospira platensis)." JAIDS: Journal of Acquired Immune Deficiency Syndromes & Human Retrovirology. 18, 1, May 1998: 7-12.
^ Khan, M., et al. "Protective effect of Spirulina against doxorubicin-induced cardiotoxicity." Phytotherapy Research. 2005 Dec;19(12):1030-7.
^ Wang, Y., et al. "Dietary supplementation with blueberries, spinach, or spirulina reduces ischemic brain damage." Experimental Neurology. May, 2005 ;193(1):75-84.
^ Gemma, C., et al. "Diets enriched in foods with high antioxidant activity reverse age-induced decreases in cerebellar beta-adrenergic function and increases in proinflammatory cytokines." Experimental Neurology. July 15, 2002; 22(14):6114-20.
^ Chen, LL, et al. "Experimental study of spirulina platensis in treating allergic rhinitis in rats." 中南大学学报(医学版) = Journal of Central South University (Medical Sciences). Feb. 2005. 30(1):96-8.
^ Mir Misbahuddin, AZM Maidul Islam, Salamat Khandker, Ifthaker-Al-Mahmud, Nazrul Islam and Anjumanara. Efficacy of spirulina extract plus zinc in patients of chronic arsenic poisoning: a randomized placebo-controlled study. (Risk factors ). Journal of Toxicology: Clinical Toxicology. 44.2 (March 2006): p135(7).
^ Simpore, J., et al. "Nutrition Rehabilitation of HIV-Infected and HIV-Negative Undernourished Children Utilizing Spirulina." Annals of Nutrition & Metabolism. 49, 2005: 373-380.
^ Mao, TK, et al. "Effects of a Spirulina-based dietary supplement on cytokine production from allergic rhinitis patients." Journal of Medicinal Food. Spring 2005;8(1):27-30.
^ Torres-Duran, Ferreira-Hermosillo, & Juarez-Oropeza. (2007). Antihyperlipemic and antihypertensive effects of Spirulina maxima in an open sample of mexican population: A preliminary report. Lipids in Health and Disease. 6, 33
^ IIMSAM, Permanent Observer Mission to the United Nations
^ Characterization of Spirulina biomass for CELSS diet potential. Normal, Al.: Alabama A&M University, 1988.
^ Cornet J.F., Dubertret G. "The cyanobacterium Spirulina in the photosynthetic compartment of the MELISSA artificial ecosystem." Workshop on artificial ecological systems, DARA-CNES, Marseille, France, October 24-26, 1990

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