‘‘Dietary Guidelines for Americans 2005.’’ January 12,
2005.<http://www.healthierus.gov/dietaryguidelines>
Whfoods.org. ‘‘Soybeans.’’ World’s Healthiest Foods, undated,
accessed April 26, 2007.<http://www.whfoods.com/>Helen M. DavidsonSpirulina
Definition
Spirulina is a genus of blue-green algae used as a
nutritional supplement. Blue-green algae, microscopic
fresh-water organisms, are also known as cyanobacte-
ria. Their color is derived from the green pigment
of chlorophyll, and the blue from a protein called phy-
cocyanin. The species most commonly recommended
for use as a nutritional supplement are Spirulina
maximaandSpirulina platensis. These occur naturally
in warm, alkaline, salty, brackish lakes, but are also
commonly grown by aquaculture and harvested for
commercial use. Spirulina contains many nutrients,
including B vitamins, beta-carotene, gamma-linolenic
acid, iron, calcium, magnesium, manganese, potassium,
selenium, zinc, bioflavonoids, and protein.
Spirulina is composed of about 65% protein. These
proteins are complete, in that they contain all essential
amino acids, plus some nonessential ones. In that
regard, it is similar to animal protein, but does not
contain saturated fats, or residues of hormones or
antibiotics that are in some meats. Since spirulina is
normally taken in small amounts, the quantity of diet-
ary protein supplied for the average, reasonably well-
nourished person would not be significant. However, it
is a good source of trace minerals, some vitamins, bio-
flavonoids, and other phytochemicals. It also has high
digestibility and bioavailability of nutrients.Purpose
Spirulina has been used as a source of protein and
nutrients, particularly beta-carotene, by the World Health
Organization (WHO) to feed malnourished Indian chil-
dren. The program resulted in a decrease of a type of
blindness that results from inadequate dietary vitamin A.
The dose used in this year-long study was 1 gram per day.Description
There is a high vitamin B 12 content in spirulina. For
this reason, it has often been recommended as a supple-
mental source of the vitamin for vegans and other strict
vegetarians, who are unlikely to have adequate dietaryvitamin B 12. Unfortunately, spirulina is not an effective
source of the usable vitamin. Much of the vitamin B 12 is
in the form of analogs that are unusable for humans,
and may even block the active forms of vitamin B 12
consumed from other sources.
Gamma linolenic acid (GLA) is present in signifi-
cant amounts in a small percent of spirulina species.
This essential fatty acid can be used in the body to
form products that are anti-inflammatory and anti-
proliferative. It is potentially useful for individuals
with rheumatoid arthritis and diabetic neuropathy. It
may also play a role in lowering plasma triglycerides
and increasing HDL cholesterol.
Spirulina is a good source of available iron and zinc.
A study done in rats found that those consuming spir-
ulina had equivalent or better absorption than those
given a ferrous sulfate iron supplement. A small human
study of iron-deficient women had good response to iron
supplementation with spirulina, although the amounts
used were large (4 grams after each meal). Similarly, a
study of zinc deficient children found that those taking
spirulina had a superior response to those taking zinc
sulfate, and had fewer side effects.
In addition to serving as a source of nutrients
itself, spirulina has been used in the manufacture of
fermented dairy products to guarantee the survival of
the bacteria used to ferment the milk.
A stronger immune system is one claim made by
boosters of spirulina. A number of animal studies
appear to support stimulation of both antibody and
cellular types of immunity. Immune function was
markedly improved in children living in the areas
surrounding Chernobyl. The measurements wereSpirulina tablets of blue green algae.(Sheila Terry/Photo
Researchers, Inc. Reproduced by permission.)Spirulina