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Other common name(s):
Carticin, CartiladeTM, BeneFinTM, Neovastat (AE-941)
Scientific/medical name(s):
none
Description
Shark cartilage is extracted from the heads and fins of
sharks. Cartilage is a type of connective tissue that is found in the
skeletal systems of many animals, including humans. Sharks’ skeletons
are made up almost entirely of cartilage instead of bones, so they
provide a large source of cartilage. The major compounds in shark
cartilage are glycoproteins, complex sugars called mucopolysaccharides,
and calcium salts. Shark cartilage is promoted mainly as an alternative
to conventional cancer treatment, but some forms are being studied for
use along with standard therapies.
Overview
Most shark cartilage products are sold as dietary supplements
as pills or powders, and have not been tested for effectiveness,
safety, or to show how much of the product is actually cartilage.
Available scientific evidence does not support claims that the shark
cartilage that is sold as a food supplement is an effective treatment
for cancer, osteoporosis, or any other disease. One shark cartilage
product, called AE-941, has undergone early phases of development as a
new drug.
Although some laboratory and animal studies have shown that
components in shark cartilage have some ability to slow the growth of
new blood vessels, these effects have not been proven in humans. The
few small clinical studies of shark cartilage products published to
date have not shown any benefit against cancer; however, further
clinical trials of the supplements and of a purified cartilage extract
are currently under way.
How is it promoted for use?
Supporters believe that shark cartilage supplements or
cartilage from other animals, such as cows, slow or stop the growth of
cancer (see also Bovine Cartilage).
Shark cartilage, according to supporters, contains proteins that stop
angiogenesis, the process of blood vessel development. Tumors need a
network of blood vessels to survive and grow, so cutting off the
tumor's blood supply starves it of nutrients, causing it to shrink or
disappear.
Some supporters also claim that shark cartilage can help
against other diseases such as osteoporosis, arthritis, psoriasis,
macular degeneration, and inflammation of the intestinal tract.
What does it involve?
Shark cartilage is usually taken by mouth as a capsule,
powder, or liquid extract, but some people have trouble taking it by
mouth because of the strong fishy smell and taste. It is also sometimes
used as an enema. The dose and length of treatment varies widely.
Manufacturers often recommend large doses (up to 1 cup a day). Because
they are often sold as dietary supplements, there is no assurance that
they contain the cartilage or its main compounds.
Chondroitin, a supplement often used along with glucosamine to help
arthritis, is also made from cartilage. Either bovine or shark
cartilage may be used to produce chondroitin.
Shark cartilage dietary supplements are different from AE-941, a liquid
shark extract known as Neovastat. This extract is regulated by the Food
and Drug Administration as an investigational new drug. AE-941 is used
in carefully controlled clinical trials for people who have agreed to
be part of the study.
What is the history behind
it?
A New York surgeon named John Prudden began investigating the
use of cartilage in the early 1950s. He used powdered bovine (cow)
cartilage to help heal the wounds of surgical patients, and later used
it to treat cancer. He reported that over half of the patients he
treated had their tumors shrink, but the results have not been repeated
in other studies.
Since then, many kinds of cartilage such as pig, sheep, chicken, cow,
and shark have been studied. After the 1992 publication of a popular
book entitled Sharks Don't Get Cancer, written by I. William Lane, PhD,
shark cartilage supplements became very popular among people interested
in alternative medicine. The idea was that since sharks do not appear
to develop as much cancer as humans, there may be something in their
systems that protects them from getting cancer.
Interest in shark cartilage increased after a television news magazine
aired a segment in 1993 that showed a study of patients with advanced
cancer in Cuba who had gone into remission after being treated with
shark cartilage. The results have not been published in a peer-reviewed
medical journal, however. The National Cancer Institute (NCI) later
concluded that the results of the Cuban study were “incomplete and
unimpressive.”
According to the US Food and Drug Administration and the Federal Trade
Commission, some manufacturers of shark cartilage supplements have been
fined and/or forced to remove their products from the market for making
unproven claims that they have cancer-fighting abilities. Such claims
can only be made for drugs with proven effects.
Finding drugs that halt the spread of cancer by stopping the growth of
blood vessels has been the subject of many conventional research
studies in recent years. Some researchers believe that the therapy
(called anti-angiogenesis therapy) holds a great deal of promise for
people with certain types of cancer. A number of anti-angiogenesis
drugs are currently being studied, and one is already approved to treat
certain cancers. In addition, several drugs that were approved for
other uses, including cancer treatment, have anti-angiogenic effects.
These are now being studied more carefully for their role in
anti-angiogenesis. Some researchers are trying to purify
anti-angiogenic compounds from cartilage. But the most promising
anti-angiogenic substances now in existence are those that have been
purified from sources other than cartilage or have been made in
laboratories.
What is the evidence?
The consensus of available scientific evidence does not
support claims that whole shark cartilage supplements are an effective
treatment for cancer in humans. Although studies using bovine and shark
cartilage in people with cancer began in the early 1980s, few have been
published. The scientific truth of many of these studies is open to
question because they do not describe how treatment was given, how
patients were assessed, long-term survival outcomes, or information
about the cartilage used and its components.
Some experiments have shown that some forms of shark cartilage possess
a modest ability to slow the growth of new blood vessels in laboratory
cell cultures and in animals, but the effects on humans are not known.
According to one review, results from 9 clinical series of patients
receiving shark cartilage were mixed. None of the series were done
under strict scientific controls.
In one clinical trial involving about 50 patients, researchers
concluded that shark cartilage supplements had no effect on patients
with advanced-stage cancers. When a more recent placebo-controlled
clinical trial tested shark cartilage in more than 80 patients with
advanced cancer, again no benefit was found. "It wasn't well tolerated,
there wasn't any suggestion of benefit in terms of quality of life,
there wasn't any suggestion of benefit in terms of survival," commented
Charles L. Loprinzi, the physician who authored the study report.
Researchers generally agree that the protein molecules in shark
cartilage may be too large to be absorbed by the digestive tract and
are simply excreted without ever reaching tumors in the body. However,
some scientists have suggested that these substances may be more
readily absorbed when taken in a liquid form.
One study concluded that a liquid shark cartilage extract taken by
mouth (AE-941, Neovastat) effectively slowed the growth of new blood
vessels in healthy men, suggesting to the study authors that the active
ingredients in liquid shark cartilage were available for use by the
body's healing systems.
A small study of the extract found that larger doses were better than
smaller doses at prolonging survival in patients with advanced kidney
cancer. A larger study was then done. While the results of this study
have not been published, the manufacturer has stopped testing its use
against kidney cancer, suggesting that the results may not have been
positive. The NCI is now sponsoring a large, placebo-controlled study
of the extract along with conventional therapies for the treatment of
advanced lung cancer.
However, extracted chemicals or substances are different from
supplements made of shark cartilage. Studies that use extracts are not
expected to have the same results as studies that use the whole
supplement.
Are there any possible
problems or complications?
Shark cartilage is not thought to be toxic, although it has
been known to cause nausea, indigestion, fatigue, fever, and dizziness
in some people. It may affect liver function, so ask your doctor before
taking it if you have any kind of liver disease. It may also slow down
the healing process for people recovering from surgery. People with a
low white blood cell count should not take shark cartilage enemas,
because there is a risk of life-threatening infection. Children should
not take it because it could interfere with body growth and
development.
Allergic reactions are possible. People with seafood
allergies should avoid shark cartilage and chondroitin that is made
from it. Women who are pregnant or breast-feeding should also avoid
these supplements.
It is not known whether shark cartilage could cause any
problems from interactions with other medicines. Relying on this type
of treatment alone, and avoiding or delaying conventional medical care,
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 ordered
from our toll-free number (1-800-ACS-2345).
References
Batist G, Patenaude F, Champagne P, et al. Neovastat (AE-941)
in refractory renal cell carcinoma patients: report of a phase II trial
with two dose levels. Ann
Oncol. 2002;13:1259-1263.
Berbari P, Thibodeau A, Germain L, et al. Antiangiogenic effects of the
oral administration of liquid cartilage extract in humans. J Surg Res.
1999;87;108-113.
Cassileth B. Evaluating complementary and alternative therapies for
cancer patients. CA
Cancer J Clin. 1999;49:362-375.
Ebube NK, Mark W, Hahm H. Preformulation studies and characterization
of proposed chondroprotective agents: glucosamine HCl and chondroitin
sulfate. Pharm Dev
Technol. 2002;7:457-469.
Ernst E, Cassileth B. How useful are unconventional cancer treatments? Eur J Cancer.
1999;35:1608-1613.
Federal Trade Commission. FTC v Heritage Health Products Company (suit
filed April 16, 2004). Available at:
www.ftc.gov/os/caselist/heritagehealth/040427stipheritagehealth.pdf.
Accessed July 11, 2007.
Federal Trade Commission. Complaints. Available at:
www.ftc.gov/os/1998/09/9723071.cmp.htm,
www.ftc.gov/os/1999/09/bodysystemcmp.htm, and
www.ftc.gov/os/2001/08/formorcmp.htm. Accessed July 11, 2007.
Finkelstein JB. Sharks do get cancer: few surprises in cartilage
research. J Natl Cancer
Inst. 2005;97:1562-1563.
Food and Drug Administration. Company ordered to halt sales of
unapproved drugs, reimburse buyers. FDA Consumer Magazine,
September-October 2004. Available at:
http://www.fda.gov/fdac/departs/2004/504_upd.html#sales. Accessed July
11, 2007.
Loprinzi CL, Levitt R, Barton DL, et al, and the North Central Cancer
Treatment Group. Evaluation of shark cartilage in patients with
advanced cancer: a North Central Cancer Treatment Group trial. Cancer.
2005;104:176-182.
Medline Plus. Herbs and supplements: Shark cartilage 2006. Available
at:
http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-sharkcartilage.html.
Accessed July 11, 2007.
Memorial Sloan-Kettering Cancer Center. About herbs: Shark cartilage.
2006. Available at: www.mskcc.org/mskcc/html/69374.cfm. Accessed July
11, 2007.
Miller DR, Anderson GT, Stark JJ, Granick JL, Richardson D. Phase I/II
trial of the safety and efficacy of shark cartilage in the treatment of
advanced cancer. J Clin
Oncol. 1998;16:3649-3655.
Ostrander GK. Cheng KC. Wolf JC. Wolfe MJ. Shark cartilage, cancer and
the growing threat of pseudoscience. Cancer Research.
2004;64:8485-8491.
National Cancer Institute Physician Data Query (PDQ). Cartilage (Bovine
and Shark). 2006. Available at:
www.cancer.gov/cancertopics/pdq/cam/cartilage/healthprofessional.
Accessed July 11, 2007.
Raloff J. A fishy therapy: A thriving but controversial dietary
supplement. Science News Online. 2005; 167(10):154. Available at:
www.sciencenews.org/articles/20050305/bob9.asp. Accessed July 11, 2007.
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.
Revised: 07/20/2007
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