Spirulina (dietary supplement)

Spirulina tablets

Spirulina is a human and animal food or nutritional supplement made primarily from two species of cyanobacteria: Arthrospira platensis and Arthrospira maxima.

Arthrospira is cultivated worldwide, 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.

Etymology

These maxima and platensis species were once classified in the genus Spirulina. There is now agreement that they are in fact Arthrospira; nevertheless, and somewhat confusingly, the older term Spirulina remains in use for historical reasons.

Ecology

Main article: Arthrospira

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

Historical use

Spirulina was 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. The Aztecs called it "techuitlatl".

Spirulina was found in abundance at Lake Texcoco by French researchers in the 1960s, but there is no reference to its use by the Aztecs as a daily food source after the 16th century, probably due to the draining of the surrounding lakes for agricultural and urban development. The first large-scale spirulina production plant, run by Sosa Texcoco, was established there in the early 1970s.

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

Spirulina may have an even longer history in Chad, as far back as the 9th century Kanem Empire.^{[citation needed]} 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.

Cultivation

Most cultivated spirulina is produced in open-channel raceway ponds, with paddle-wheels used to agitate the water. The largest commercial producers of spirulina are located in the United States, Thailand, India, Taiwan, China, Pakistan, Burma (a.k.a. Myanmar) and Chile .

Nutrient and vitamin content

Protein and amino-acid content

Spirulina contains about 60% (51–71%) protein. It is a complete protein 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. Overall, while spirulina is often marketed as an excellent source of protein, it is no better in this regard than milk or meat (in that they are all complete proteins), and is approximately 30 times more expensive per gram of protein.

Vitamin B12

Spirulina is not considered to be a reliable source of Vitamin B₁₂. The standard B₁₂ assay, using Lactobacillus leichmannii, shows spirulina to be a minimal source of bioavailable vitamin B₁₂. Spirulina supplements contain predominantly pseudovitamin B₁₂, which is biologically inactive in humans. Companies which grow and market spirulina have claimed it to be a significant source of B₁₂ on the basis of alternate, unpublished assays, although their claims are not accepted by independent scientific organizations. The American Dietetic Association and Dietitians of Canada in their position paper on vegetarian diets state that spirulina cannot be counted on as a reliable source of active vitamin B₁₂. The medical literature similarly advises that spirulina is unsuitable as a source of B12.

Other nutrients

Spirulina's lipid content is about 7% by weight, and is rich in gamma-linolenic acid (GLA), and also provides alpha-linolenic acid (ALA), linoleic acid (LA), stearidonic acid (SDA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA). Spirulina contains vitamins B₁ (thiamine), B₂ (riboflavin), B₃ (nicotinamide), B₆ (pyridoxine), B₉ (folic acid), vitamin C, vitamin D, vitamin A and vitamin E. It is also a source of potassium, calcium, chromium, copper, iron, magnesium, manganese, phosphorus, selenium, sodium and zinc. Spirulina contains many pigments which may be beneficial and bioavailable, including beta-carotene, zeaxanthin, chlorophyll-a, xanthophyll, echinenone, myxoxanthophyll, canthaxanthin, diatoxanthin, 3'-hydroxyechinenone, beta-cryptoxanthin and oscillaxanthin, plus the phycobiliproteins c-phycocyanin and allophycocyanin.

Possible health benefits and risks

Safety

Quality-related safety issues

Spirulina is a form of cyanobacterium, some of which are known to produce toxins such as microcystins, BMAA, and others. Because spirulina is a dietary supplement, the United States Food and Drug Administration does not regulate the production and quality of the product. Currently, no standard exists to regulate the safety of spirulina in the U.S. The U.S. National Institutes of Health describes spirulina supplements as "possibly safe" for adults, provided they are free of microcystin contamination, but when contaminated by microcystins "likely unsafe" for children as they are more susceptible to the toxins which can contaminate spirulina supplements.

Safety issues for certain target groups

Due to very high Vitamin K content, patients undergoing anticoagulant treatments should not change consumption patterns of Spirulina without seeking medical advice to adjust the level of medication accordingly.

As all protein-rich foods, Spirulina contains the essential amino acid phenylalanine (2.6-4.1 g/100 g), which should be avoided by people who have the rare genetic disorder phenylketonuria, where the body cannot metabolize this amino acid and it builds up in the brain, causing damage.

In vitro research

Spirulina has been studied in vitro against HIV, as an iron-chelating agent, and as a radioprotective agent. Animal studies have evaluated spirulina in the prevention of chemotherapy-induced heart damage, stroke recovery, age-related declines in memory, diabetes mellitus, in amyotrophic lateral sclerosis, and in rodent models of hay fever. Mouse studies suggest that spirulina has little effect on the metabolism, and therefore is unlikely to be effective as a weight-loss agent.

Human research

In humans, small studies have been undertaken evaluating spirulina in undernourished children, as a treatment for the cosmetic aspects of arsenic poisoning, in hay fever and allergic rhinitis, in arthritis,^{[Requires clarification, since IL-2 is typically thought of as pro-inflammatory]} in hyperlipidemia and hypertension, and as a means of improving exercise tolerance.

At present, these studies are considered preliminary. According to the U.S. National Institutes of Health, at present there is insufficient scientific evidence to recommend spirulina supplementation for any human condition, and more research is needed to clarify its benefits, if any.

Organic certification

Until recently, much spirulina was certified organic. In 2002, the USDA's National Organic Standards Board voted to disallow the use of Chilean nitrate. They granted a three-year window to spirulina producers, which expired in 2006. As a result, leading spirulina manufacturers have stopped labeling their spirulina as organic, citing safety concerns of nitrate alternatives.

Parry Nutraceuticals was the first company to introduce Organic Spirulina as per the new USDA NOP standards using pure vegetarian nitrogen sources. This is an Indian company, and the spirulina is grown in India.

Advocates

The United Nations World Food Conference in 1974 lauded spirulina as the 'best food for the future'^{[citation needed]}. Recognizing the inherent potential of spirulina in the sustainable development agenda, several Member States of the United Nations came together to form an intergovernmental organization named the Intergovernmental Institution for the use of Micro-algae Spirulina Against Malnutrition (IIMSAM). IIMSAM aspires to build a consensus with the UN Member States, international community and other stakeholders to make spirulina a key driver to eradicate malnutrition, achieve food security and bridge the health divide throughout the world.

Both NASA (CELSS) and the European Space Agency (MELISSA) proposed Spirulina as one of the primary foods to be cultivated during long-term space missions.

See also

• Algaculture - commercial farming of algae
• Aphanizomenon flos-aquae
• Aphanizomenon flos-aquae (dietary supplement)
• Arthrospira
• Chlorella - an alga with potential food and fuel uses
• Spirulina (genus)