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Spirulina (Food Supplement) |
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 Spirulina
is the common name for human and animal food supplements produced primarily from
two species of cyanobacteria: Arthrospira platensis, and Arthrospira maxima.
These and other Arthrospira species were once classified in the genus Spirulina.
There is now agreement that they are distinct genera, and that the food species
belong to Arthrospira; nonetheless, the inaccurate term Spirulina remains the
popular name. Spirulina is cultivated around the world, and is used as a human
dietary supplement, available in tablet, flake, and powder form. It is also used
as a feed supplement in the aquaculture and poultry industries.
History
Spirulina is believed to have been a food source for the Aztecs in 16th century
Mexico, as its harvesting from Lake Texcoco and sale as cakes is described by
one of Cortes' soldiers. The Aztecs called it Tecuitlatl, 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 extablished there in the early 1970s.
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
Dihe 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.
Nutrients and Other Chemicals
Protein
Spirulina contains unusually high amounts of protein, between 55 and 77% by dry
weight, depending upon the source. It is a complete protein, containing all
essential amino acids, though with reduced amounts of methionine, cysteine, and
lysine, as compared to standard proteins such as that from meat, eggs, or milk;
it is, however, superior to all standard plant protein, such as that from
legumes.
Essential Fatty Acids
Spirulina is an unusually rich source of gamma-linolenic acid (GLA) and also
provides alpha-linolenic acid (ANA), linoleic acid (LA), stearidonic acid (SDA),
eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid
(AA).
Vitamins
Spirulina contains vitamin B1 (thiamine), B2 (riboflavin), B3 (nicotinamide), B6
(pyridoxine), B9 (folic acid), B12 (cyanocobalamin), vitamin C, vitamin D, and
vitamin E. The bioavailability of vitamin B12 in Spirulina is in dispute.
Several biological assays have been used to verify the presence of vitamin B12.
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. However, this assay does not
actually differentiate between human bioavailable and non-human bioavailable
B12. A more recently developed assay performed by a grower of spirulina has
shown Spirulina to be a significant source of bioavailable B12.
Minerals
Spirulina is a rich source of potassium, and also contains calcium, chromium,
copper, iron, magnesium, manganese, phosphorus, selenium, sodium, and zinc.
Photosynthetic Pigments
Spirulina contains many pigments including chlorophyll-a, xanthophyll,
beta-carotene, echinenone, myxoxanthophyll, zeaxanthin, canthaxanthin,
diatoxanthin, 3'-hydroxyechinenone, beta-cryptoxanthin, oscillaxanthin, plus the
phycobilins c-phycocyanin and allophycocyanin.
Evidence of Health and Healing Effects
Advocates frequently overstate their claims of Spirulina's health and healing
properties, though often there is research upon which such claims are based.
Conversely, health food detractors often dismiss all such claims without
acknowledging existing research. Two online publications exemplify these
opposing positions, respectively: Super foods For Optimum Health: Chlorella and
Spirulina, and Wellness Letter on Blue Green Algae. 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 may suggest the possibility of similar results in humans, but
cannot be taken as proof of human effects. Animal research provides stronger
evidence, but again, does not represent proof of similar effects in humans. The
results of Clinical trials are the best evidence available.
In Vitro Research
Spirulina extract inhibits HIV replication in human T-cells, peripheral blood
mononuclear cells (PBMC), and Langerhans cells.
Animal Research
Spirulina helps prevent heart damage caused by chemotherapy using Doxorubicin,
without interfering with its anti-tumor activity. Spirulina reduces the severity
of strokes and improves recovery of movement after a stroke; reverses
age-related declines in memory and learning; and prevents and treats hay fever.
Clinical Trials
Spirulina is effective for the clinical improvement of melanosis and keratosis
due to chronic arsenic poisoning; improves weight-gain and corrects anemia in
both HIV-infected and HIV-negative undernourished children; and protects against
hay fever.
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