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Other common
name(s): sun chlorella, green algae
Scientific/medical
name(s): Chlorella
pyrenoidosa and Chlorella
vulgaris are the species most used in supplements
Description
Chlorella is a single-celled freshwater alga. These algae
contain large amount of chlorophyll, the chemical that gives plants
their green color. Chlorophyll is an essential compound for
photosynthesis, the process by which plants convert light into chemical
energy. Chlorophyll is also available in green leafy vegetables.
Overview
Chlorella is widely used in Japan for a variety of health
conditions; however, available scientific studies do not support its
effectiveness for preventing or treating cancer or any other disease in
humans.
How is it promoted for use?
Chlorella is promoted for a wide range of herbal remedies.
Proponents claim it kills several types of cancer, fights bacterial and
viral infections, enhances the immune system, increases the growth of
"friendly" germs in the digestive tract, lowers blood pressure and
cholesterol levels, and promotes healing of intestinal ulcers,
diverticulosis, and Crohn's disease. It is said to "cleanse" the blood,
digestive system, and the liver.
Supporters state that chlorella supplements increase the level
of albumin in the body. Albumin is a protein normally present in the
bloodstream, and promoters claim it is protective against diseases such
as cancer, diabetes, arthritis, AIDS, pancreatitis, cirrhosis,
hepatitis, anemia, and multiple sclerosis. Chlorella is said to prevent
cancer through its ability to cleanse the body of toxins and heavy
metals. Some Web sites describe it as the perfect food, saying that it
regulates blood sugar, kills cancer cells, strengthens the immune
system, and even "reverses the aging cycle." Available scientific
evidence does not support these claims. Because of this, the U.S. Food
and Drug Administration (FDA) has warned the proprietors of at least
one Web site to stop making unproven statements about chlorella's
benefits.
Chlorella contains vitamin C and carotenoids, both of which
are antioxidants (see our documents Beta Carotene,
and Vitamin C).
Antioxidants are compounds that block the action of free radicals,
activated oxygen molecules that can damage cells. Chlorella is also
reported to contain high concentrations of B-complex vitamins (see the
document Vitamin B Complex).
What does it involve?
Chlorella is available in tablets, liquid extracts, and as a
powder. Some herbalists recommend 2 to 3 grams per day, though higher
doses may be suggested for "detoxification." A few people take up to 10
or 15 grams (2 to 3 teaspoons) per day. Although it may be taken on its
own, many supporters suggest mixing the powdered form of chlorella into
foods made with flour, such as bread or cookies.
What is the history behind it?
Chlorella was discovered in the late 19th century. Due to its
high protein concentration and rapid growth rate, chlorella was
investigated after World War II as a possible commercial food source.
In the 1960s, some investigators claimed that the algae decreased the
side effects of chemotherapy and slowed the growth of some cancer
cells. Most of the research has been conducted in Japan, where
chlorella is a top-selling dietary supplement.
What is the evidence?
Available scientific evidence does not support claims that
chlorella is effective against cancer or other diseases in humans.
Limited laboratory and animal research suggests that these algae may
have some anti-cancer properties. Chlorella powder may inhibit the
activity of some molecules involved in the growth of cancer cells.
One investigation concluded that a protein extract from one
type of chlorella prevented the spread of cancer cells in mice. Another
study in mice suggested that the extract reduced the side effects of
chemotherapy treatment without affecting the potency of anti-cancer
medications. A 2001 study from Brazil showed that an extract of
chlorella prolonged the survival of mice that were injected with tumor
cells. However, study results for extracted chemicals might not be
consistent with studies using the whole plant. Further studies are
needed to determine whether the results apply to humans.
In 2003, a supplement derived from chlorella was given to
healthy adults to learn whether it boosted immune response to the flu
shot. The study found there was no significant difference in antibodies
between the group that received the chlorella supplements and the one
that did not.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike companies that produce
drugs (which must provide the FDA with results of detailed testing
showing their product is safe and effective before the drug is approved
for sale), the companies that make supplements do not have to show
evidence of safety or health benefits to the FDA before selling their
products. Supplement products without any reliable scientific evidence
of health benefits may still be sold as long as the companies selling
them do not claim the supplements can prevent, treat, or cure any
specific disease. Some such products may not contain the amount of the
herb or substance that is written on the label, and some may include
other substances (contaminants). Though the FDA has written new rules
to improve the quality of manufacturing processes for dietary
supplements and the accurate listing of supplement ingredients, these
rules do not take full effect until 2010. And, the new rules do not
address the safety of supplement ingredients or their effects on health
when proper manufacturing techniques are used.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
Although chlorella appears to be safe in those who are not
allergic, no research has been done in humans to learn whether it
causes negative side effects or what can be expected from long-term
use. If hives or a rash develops, stop taking chlorella and seek
medical attention immediately. Relying on this type of treatment alone
and avoiding or delaying conventional medical care for cancer may have
serious health consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Barrett S. Mercola gets second warning letter. Consumer Health
Digest #06-41. October 11, 2006. National Council Against Health Fraud
Web site. http://www.ncahf.org/digest06/06-41.html. Accessed June 4,
2008.
Cheng FC, Lin A, Feng JJ, Mizoguchi T, Takekoshi H, Kubota H,
Kato Y, Naoki Y. Effects of chlorella on activities of protein tyrosine
phosphatases, matrix metalloproteinases, caspases, cytokine release, B
and T cell proliferations, and phorbol ester receptor binding. J Med Food.
2004;7:146-152.
Halperin SA, Smith B, Nolan C, Shay J, Kralovec J. Safety and
immunoenhancing effect of a Chlorella-derived dietary supplement in
healthy adults undergoing influenza vaccination: randomized,
double-blind, placebo-controlled trial. CMAJ.
2003;169:111-177.
Justo GZ, Silva MR, Queiroz ML. Effects of the green algae
Chlorella vulgaris on the response of the host Hematopoietic system to
intraperitoneal ehrlich ascites tumor transplantation in mice. Immunopharmacol Immunotoxicol.
2001;23:119-132.
Konishi F, Mitsuyama M, Okuda M, Tanaka K, Hasegawa T, Nomoto
K. Protective effect of an acidic glycoprotein obtained from culture of
Chlorella vulgaris against myelosuppression by 5-fluorouracil. Cancer Immunol Immunother.
1996;42:268-274.
Tanaka K, Yamada A, Noda K, Hasegawa T, Okuda M, Shoyama Y,
Nomoto K. A novel glycoprotein obtained from Chlorella vulgaris strain
CK22 show antimetastatic immunopotentiation. Cancer Immunol Immunother.
1998;45:313-320.
Note:
This
information may not cover all possible claims, uses, actions,
precautions, side effects or interactions. It is not intended as
medical advice, and should not be relied upon as a substitute for
consultation with your doctor, who is familiar with your medical
situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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