Spirulina

Spirulina is a microalga that can be consumed by humans and animals. It is usually taken by humans as a nutritional supplement and is made primarily from two species of cyanobacteria: Arthrospira platensis and Arthrospira maxima.

Arthrospira is cultivated worldwide; used as a 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.

NUTRIENT AND VITAMIN CONTENT

Protein and amino-acid content

Dried Spirulina contains about 60% (51–71%) protein. It is a complete protein containing all essential amino acids, though with reduced amounts ofmethionine, 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. The U.S. National Library of Medicine stated that spirulina was no better than milk or meat as a protein source, and was approximately 30 times more expensive per gram.

Vitamin B12

Spirulina is not considered to be a reliable source of 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which grow and market spirulina have claimed it to be a significant source of B₁₂ on the basis of alternative, unpublished assays, although their claims are not accepted by independent scientific organizations. The American Dietetic Associationand 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.