- Shark cartilage
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Shark cartilage is a dietary supplement made from the dried and powdered cartilage of a shark; that is, from the tough material that composes a shark's skeleton. Shark cartilage is claimed to combat and/or prevent a variety of illnesses, most notably cancer. It is often marketed under the names Carticin, Cartilade, or BeneFin. A derivative of it named Neovastat was tested by AEterna Zentaris as an angiogenesis inhibitor and showed promising results in animals. Two clinical trials of Neovastat were completed in 2007,[1] showing negative results.[2]
The benefits of this supplement have not been scientifically proven, nor has shark cartilage been reviewed by the U.S. Food and Drug Administration (FDA). However, its pervasive use is due to the mistaken notion that sharks do not get cancer and that shark cartilage contains angiogenesis inhibitor. [3] This idea became popular with the best-selling book Sharks Don't Get Cancer by Dr. William Lane, published in 1992. This assertion even appears in the film on sharks at the Monterey Bay Aquarium (although the aquarium does not endorse the use of shark cartilage), and in commercials for the National Geographic Channel.
Contents
Criticism and controversy
Proponents of shark cartilage are encouraged by anecdotal evidence from users as to its efficacy. The proponents also cite studies that show that shark cartilage has had some success in preventing angiogenesis, the growth of new blood vessels from pre-existing vessels. While angiogenesis is often a normal function, it is also consistent with the growth of malignant tumors. They argue too, that very little research (in the quantity and quality of studies) has been conducted, and thus the benefits cannot be scientifically disputed.
Opponents cite existing studies of shark cartilage on a variety of cancers that produced negligible to non-existent results in the prevention or treatment of cancer.[4] Most notable among these was a breast-cancer trial conducted by the Mayo Clinic that stated that the trial "was unable to demonstrate any suggestion of efficacy for this shark cartilage product in patients with advanced cancer." [5] The results of another clinical trial were presented at the 43rd annual meeting of the American Society for Clinical Oncology. In that study (sponsored by the National Cancer Institute), "researchers did not find a statistical difference in survival" between patients receiving shark cartilage and those taking a placebo.[1] Scientific evidence does not support the efficacy of shark cartilage nor the ability of effective components to remove cancer cells. The fact that people believe eating shark cartilage can cure cancer shows the serious potential impacts of pseudoscience.[2]
Detractors also purport that previous beliefs in regards to sharks and cancer have been overturned, as forty-two varieties of cancer have now been discovered in sharks and related species. Also, many opponents[who?] feel that non-existent (or even limited) results do not justify the rampant over-fishing of many endangered species of sharks, further threatening their extinction.[6]
The protein involved in inhibiting angiogenesis would have to be injected into the bloodstream to have any effect on the cancer in the body. When a patient takes shark cartilage orally the protein is digested before it reaches the area of the tumor. Not all cancers rely on angiogenesis for energy.
Legal action
In the summer of 2004, Lane Labs, the manufacturers of BeneFin, was ordered to cease the promotion of BeneFine as a treatment or cure for cancer, as they had not conducted any research as to their claims for the product, much less reported any potential side effects. Thus, the FDA ordered Lane Labs to "pay restitution to all of its customers from September of 1999 to the present."[7]
Notes
- ^ Clinicaltrials.gov search for Neovastat.
- ^ Shark cartilage flounders; flaxseed shows promise.
- ^ Shark Cartilage Contains Inhibitors of Tumor Angiogenesis
- ^ "Shark Cartilage Shows No Benefit as a Therapeutic Agent for Lung Cancer." 1 June 2007, <http://www.newswise.com/articles/view/530517/>
- ^ Loprinzi CL, Levitt R, Barton DL, et al. (July 2005). "Evaluation of shark cartilage in patients with advanced cancer: a North Central Cancer Treatment Group trial". Cancer 104 (1): 176–82. doi:10.1002/cncr.21107. PMID 15912493.
- ^ "Facts endangering sharks: Cartilage." Shark Foundation, Foundation for research and the preservation of sharks. 26 January 2006, 18:19 UTC. 26 January 2006, 18:34 <http://www.shark.ch/Preservation/Facts/cartilage.html>.
- ^ "Warning Against BeneFin." About.com. 26 January 2006, 20:02 <http://coloncancer.about.com/b/a/101392.htm>
References
External links
General
- Information on shark cartilage, from WebMD.com
- Do Sharks Hold Secret to Human Cancer Fight?, National Geographic
- Aetna InteliHealth, lists study results
Advocates
- REAL LIFE's Shark Cartilage Information Exchange, began in 1995
- Sharks Don't Get Cancer: How Shark Cartilage Could Save Your Life, William Lane, Ph.D., 1992. (ISBN 0-89529-520-2)
- The Angiogenesis Foundation
Opponents
- Shark Cartilage, American Cancer Society
- "Operation Cure.all" Nets Shark Cartilage Promoters, Federal Trade Commission
- Facts endangering sharks: Cartilage, The Shark Foundation
See also
Categories:- Dietary supplements
- Sharks
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