Blue-green algae are a diverse group of microscopic plants rarely used for human food. The exception is Spirulina, which has become widely available as a food ingredient within the last twenty years. It is a nutraceutical food with rather unique phytonutrients and characteristics. Spirulina can be used in a variety of healthy food applications. Wild Spirulina platensis, (or Arthrospira as it is sometimes called), grows in sunny warm-water volcanic soda lakes throughout the world. This alga thrives in waters containing high amounts of sodium carbonate with pH values above ten. Where wild Spirulina is found there are often flocks of flamingos and other animals feeding on it. Spirulina has a distinctive spiral structure with filaments of cells being about 10 microns in diameter and up to 1,000 microns in length.
Spirulina is the only blue-green algae commercially cultivated for food use. Modern Spirulina farms have specially designed raceway type ponds using paddlewheel circulation for cultivation. The tiny spiral shaped algae are harvested by multi-stage filtration, rinsed and spray-dried. Spray drying evaporates the water and with minimal heating, preserving nutritive value. It is supplied as very fine dark-blue-green powder, usually packed in sealed oxygen barrier type shipping containers. Since time immemorial humans have eaten Spirulina The Spaniards observed the Aztecs utilizing it for food. Indigenous people around Lake Chad in Africa still eat 'dihe' as they call it. In the West it was first mass-produced in Mexico City where it was growing in a soda works. It was first sold commercially as food in the early 1980s, and since then it has become popular as a health food for "energy" and a dieting aid. Spirulina is today consumed as food in more than seventy-five countries worldwide.
Considerable potential exists for Spirulina to be used in energy or granola bars, snacks, sports pastas, and specialty juices and liquid meal replacements. It is especially good for athletes, the aging and others with special health concerns and those needing extra immune system support. Health benefits are found in animal and human studies at feeding levels starting at an equivalent of about one-gram per day, assuming a one-hundred-sixty pound person. Pure Spirulina is a dark blue-green frne powder with a mild seaweed taste. It easily mixes with other dry powder ingredients. While not completely soluble, it suspends nicely in most liquids with gentle agitation. When used in light colored foods at levels of less than five percent it turns the food a pale green, at one percent or less it has little if any effect on color. When used at the lower levels it does not affect the taste of most foods. Commercially available blue pigment, (phycocyanin or DIC Lina-blue) extracted from is useful as a food coloring. While water soluble, it is not heat stable. In Japan it is used for coloring frozen foods and chewing gum.
Investigation is underway in regard to the anti-viral and anti-HW properties found with invitro studies of Spirulina extracts. Many in vitro and in vivo studies demonstrate even small amounts or Spirulina stimulate immune system functions, especially those mediated by macrophages. It accelerates immune system competence in young animals. Data also suggests there is synergy between Spirulina and Vitamin C. Spirulina may serve to extend Vitamin C in vivo. Other studies show Spirulina may have potential as a therapy for some kinds of cancers. In China it is used in hospitals to lower blood lipids, reduce fatigue and increase levels of IgG, IgA and IgM. It may have anti-radiation therapy potentiaL Recent work done in Macedonia reports hematological benefits for athletes in intensive training. Other studies show Spirulina may help with liver and kidney detoxification. Animals experimentally fed Spirulina were afforded significant protection from the effects of high doses of dioxin, gentamicin, cisplatin and organic mercury. Since Spirulina has a prokaryotic type of cell structure the cell wall components affect the immune system of man and animals. The thin cell wall is made of polysaccharides and muramyl peptides. Spirulina polysaccharides have both anti-oxidant and immune system stimulating properties. These polysaccharides are linked within the cell wall to muramyl peptides. Muramyl peptides are thought to be essential to humans and animals for good health. They help maintain the immune system in a state of optimal readiness and provide benefits for the central nervous system by stimulating metabolism while enhancing slow-wave sleep and may affect organ development. Chinese scientists have documented the afore mentioned phycocyanin as stimulating hematopoiesis, emulating the hormone erythropoetin. This is a potentially valuable therapy for persons suffering from certain forms of anemia or bone marrow damage.
Spirulina's cell wall contains no cellulose and is made of mucopolysaccharides. The cell wall is easily digested in the human gut. Most striking nutritionally is the high amino acid content, about sixty-two percent, and very high carotenoid pigment content, about 4 mg/gram. The carotenoids consist of about ten different kinds, mainly beta-carotene, zeaxanthin and myxoxanthophyll with small amounts of lutein and several others. Vitamin A activity is about 2,300 LU per gram. Spirulina derives its intense dark blue-green color from a mixture of pigments in addition to carotenoids. Green chlorophyll makes up about one percent while the briffiant hyacinth blue phycocyanins are at about a whopping fourteen percent. Phycocyanins are peptides, which may have health benefits. This alga contains only about seven percent fat and twenty percent of the fat is GLA, gamma-linolenic acid. GLA may have inflammation modulating properties and is itself a popular dietary supplement. Spirulina is usually a good source of iron, containing about one-mg per gram. This makes it an attractive supplement for women or athletes. It also may contain appreciable amounts of zinc, B- 12, riboflavin and thiamin.
The UN-FAO recognizes Spirulina as a potential weapon against malnutrition for the third world and has sponsored safety studies since the early 1980s. The results show Spirulina is safe and non-toxic. Testing reveals it has a no-adverse-effect level of at least l2gm[kg in mice. No acute or chronic problems, no reproductive toxicity and Spirulina is non-mutagenic.
As with mushrooms, care needs to be taken to ensure that the supplier has true Spirulina, not a potentially toxic species that looks similar. Algal toxins, heavy metals are a concern for wild-harvested lake algae. The best suppliers provide algal toxin test results and environmental contaminates like pesticides from agricultural run-off can be a for additional assurance. Visual microscopic examination together with GLA analysis can confirm authenticity. While visual identification of blue-green algae can be difficult, Spirulina is distinguished as the only filamentous blue-green algae with appreciable amounts of GLA fatty acid, (18: 3:6), about one percent by weight. GLA content should be at least 900mg/lOOgm to meet the accepted definition of Spirulina by the NNFA in the United States. Moisture should be less then seven percent. Bacterial or mold contamination are indicators of improper growing conditions, drying or storage. Color should be very dark blue-green. Carotenoid pigments should be at least 350mg/100gm. "Bright" green color indicates oxidized stale product with low carotenoid content.