The supplement called spirulina consists of one or more members of a family of blue-green algae. The name was inspired by the spiral shapes in which these plants array themselves as they grow. ^ Other blue-green algae products are also available on the market, and they are discussed in this article as well.
Spirulina grows in the wild in salty lakes in Mexico and on the African continent. It reproduces quickly, and because the individual plants tend to stick together, it is easy to harvest. Records of the Spanish conquistadors suggest that the Aztecs used spirulina as a food source; we also know that the Kanembu people of Central Africa harvested it from what is now called Lake Chad.
This plant contains high levels of various B vitamins, beta-carotene , other carotenoids, and minerals, including calcium , iron , magnesium , manganese , potassium , and zinc . It is also a source of gamma-linolenic acid (GLA) . Spirulina is a rich source of protein—dried spirulina contains up to 70% protein by weight ^ —but you'd have to eat an awful lot of spirulina capsules to obtain a significant amount of protein this way. Spirulina also contains vitamin B 12 , a nutrient otherwise found almost exclusively in animal foods. However, there's a catch: the B 12 in spirulina is not absorbable. ^ Spirulina has not been proven effective for any medical condition, and there are significant safety concerns involving all forms of blue-green algae (see Safety Issues ).
Unless you live within 35 degrees of the equator and on the shores of an alkaline lake, you will have difficulty finding spirulina anywhere but in a health food store. Most carry a number of brands of spirulina that has been dried and processed into powder or tablets.
Researchers studying spirulina's effects on health have used a variety of doses, ranging from 1 to 8.4 g daily.
What Is the Scientific Evidence for Spirulina?
There are no well-documented uses of spirulina.
Fibromyalgia is a common chronic condition whose main symptoms are specific tender points on various parts of the body, widespread musculoskeletal discomfort, morning stiffness, fatigue, and disturbed sleep. The cause of fibromyalgia is not known, and current treatments are far from completely satisfactory.
A recent study suggests that the nutritious algae Chlorella pyrenoidosamight be helpful. ^ In this double-blind, placebo-controlled trial, 37 people with fibromyalgia were given either placebo or chlorella supplements at a dose of 10 g daily. At the end of 3 months, individuals were switched to the opposite group, and then treated for an additional 3 months. The results showed significant improvements in symptoms when participants used chlorella as compared to placebo.
A double-blind, placebo-controlled trial investigated the possible weight loss effects of spirulina. ^ However, while individuals taking 8.4 g of spirulina daily lost weight, the difference between the spirulina group and the placebo group was not statistically significant . Larger and longer studies are needed to establish whether spirulina is indeed an effective treatment for obesity.