Spirulina (dietary supplement)

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Spirulina is the dried biomass of cyanobacteria (blue-green algae) that can be consumed by humans and animals. The three species are Arthrospira platensis, A. fusiformis, and A. maxima. Recent research has further moved all these species to Limnospira. L. fusiformis is also found to be insufficiently different from L. maxima to be its own species.

The genus Arthrospira was formerly classified in the genus Spirulina, hence the name.

Cultivated worldwide, spirulina is used as a dietary supplement or whole food. It is also used as a feed supplement in the aquaculture, aquarium, and poultry industries.

Biological nature

upright=1.4|thumbnail|Spirulina powder at 400×, unstained wet mount

Arthrospira species are free-floating, filamentous cyanobacteria characterized by cylindrical, multicellular trichomes in an open left-handed helix. They occur naturally in tropical and subtropical lakes with high pH and high concentrations of carbonate and bicarbonate. which belongs to photosynthetic bacteria that cover the groups Cyanobacteria and Prochlorophyta. Scientifically, a distinction exists between spirulina and the genus Arthrospira, for which the two species were originally proposed. Species of Arthrospira have been isolated from alkaline brackish and saline waters in tropical and subtropical regions. Among the various species included in the genus Arthrospira, A. platensis is the most widely distributed and is mainly found in Africa, but also in Asia. The term "spirulina" (without italicizing and usually without capitalization) remains in use for historical reasons. The Aztecs called it tecuitlatl.

Spirulina was found in abundance at Lake Texcoco by French researchers in the 1960s, but no reference to its use by the Aztecs as a daily food source was made after the 16th century, probably because of the draining of the surrounding lakes for agriculture and urban development.

During 1964 and 1965, the botanist Jean Leonard confirmed that dihe is made up of spirulina, and later studied a bloom of algae in a sodium hydroxide production facility. As a result, the first systematic and detailed study of the growth requirements and physiology of spirulina was performed as a basis for establishing large-scale production in the 1970s. and linoleic acid. In contrast to 2003 estimates, newer (2015)

Vitamin B₁₂

Spirulina contains no vitamin B₁₂ naturally, and spirulina supplements are not considered a reliable source of vitamin B₁₂, as they contain predominantly pseudovitamin B₁₂ (Coα-[α-(7-adenyl)]-Coβ-cyanocobamide), which is biologically inactive in humans. The medical literature similarly advises that spirulina is unsuitable as a source of B₁₂.

Animals and aquaculture

Various studies on spirulina as an alternative feed for animal and aquaculture have been done. and less than 4% for quail. An increase in spirulina content up to for 16 days in 21-day-old broiler male chicks resulted in yellow and red coloration of flesh, possibly due to the accumulation of the yellow pigment zeaxanthin. Pigs and rabbits can receive up to 10% of the feed and increase in the spirulina content in cattle resulted in increase in milk yield and weight. Spirulina has been established cultured striped jack, carp, red sea bream, tilapia, catfish, yellow tail, zebrafish, shrimp, and abalone, and up to 2% spirulina per day in aquaculture feed can be safely recommended. Spirulina has been studied as a potential nutritional supplement for adults and children affected by HIV, but there was no conclusive effect on risk of death, body weight, or immune response.

Spirulina was investigated to address food security and malnutrition, and as dietary support in long-term space flight or Mars missions.

Risks

Spirulina may have adverse interactions when taken with prescription drugs, particularly those affecting the immune system and blood clotting. Some spirulina supplements have been found to be contaminated with microcystins, albeit at levels below the limit set by the Oregon Health Department. but can occur if spirulina batches are contaminated with other, toxin-producing, blue-green algae. Because spirulina products are marketed as a dietary supplement, such products are made to the standards of processing and chemical purity of the manufacturer. Accordingly, spirulina supplements are regarded only as "possibly safe", provided they are free of microcystin contamination, and "likely unsafe" (especially for children) if contaminated.

Heavy-metal contamination of spirulina supplements has also raised concern. The Chinese State Food and Drug Administration reported that lead, mercury, and arsenic contamination was widespread in spirulina supplements marketed in China. One study reported the presence of lead up to 5.1 ppm in a sample from a commercial supplement. Spirulina doses of 10 to 19 grams per day over several months have been used safely. including liver damage, shock, and death.

See also

• Klamath Lake AFA
• Collaborative Inter-Governmental Scientific Research Institute
• Chlorella

References

it:Spirulina platensis