What is shark cartilage?
Scientific name / brand name / common name
The commonly used name for the preparation is shark cartilage. Commercial products are sold as Cartilate, Cartilade, BeneFin, AE-941, U-995, Neovastat, Better Shark MC and numerous other brand names.
It is claimed that a protein in shark cartilage can shrink tumour size, slow or stop the growth of cancerous cells and help reverse bone disease such as osteoporosis. (ref 1,2) Providers claim that shark cartilage is effective in cancer because of anti-angiogenic capacities. Shark cartilage is also claimed to have putative antitumor, antioxidant, anti-inflammatory and anti-atherogenic actions, although these putative actions are so far poorly supported by credible clinical research.
Administration is usually either orally in capsule form or rectally by enemas of shark cartilage mixed with sterile water. It can also be administered by subcutaneous injection but is not normally applied intravenously. From clinical studies we know that for refractory metastatic renal cell carcinoma, a specific water-soluble shark cartilage extract, AE-941 (Neovastat), 60 to 240 mL per day has been used. (ref 3,4) For the treatment of solid tumors, 30 to 240 mL daily has been used.16 For the treatment of plaque psoriasis, 30 to 240 mL per day has been used for up to 12 weeks. (ref 5) For cutaneous Kaposi’s Sarcoma, shark cartilage 3,750 to 4,500 mg per day has been used. (ref 6) Commercial products typically suggest doses ranging from 500 mg to 4.5 grams, given in two to six divided doses daily, taken either orally or by enema. (ref 7)
Ingredients
Cartilage is part of the skeletal system composed of elastic, translucent tissue. Sharks’ skeletal structure is not made of bones but of cartilage. Shark cartilage is obtained from the spiny dogfish shark Squalus acanthias and the hammered shark Sphyrna lewini and is available in either capsule or powder form. Shark cartilage products contain glycoproteins, such as phyrastitin 1 and 2.
History / providers
""Lane published a book in 1992 entitled Sharks don’t get cancer. The claim is incorrect – sharks can get cancer of their cartilage"
"
In 1963 it was discovered that tumour growth was partly dependant upon angiogenesis. (ref 8) Lane published a book in 1992 entitled Sharks don’t get cancer. (ref 1) The claim is incorrect – sharks can get cancer of their cartilage. (ref 9,10) Numerous manufacturers offer commercial preparations available as food supplements, sold without restriction, through various outlets. In 1995, over 40 brands were on the market.
In 2000 Lane was prohibited by the Federal Trade Commission from claiming that "BeneFin or any other shark cartilage product prevents, treats or cures cancer", until he can provide substantial evidence to support this claim. Since shark cartilage has been promoted as a cancer cure, there has been a measurable decline in shark populations. Providers claim that shark cartilage has an anti-angiogenic effect.
Mechanisms of action / alleged indication
Angiogenesis enables new blood vessels and, consequently, tumours to grow. All cartilage, including human, contains anti-angiogenic factors. Part of the reason human blood vessels are laid out the way they are is because the body contains factors that stop these vessels from growing. When shark cartilage is taken orally, any anti-angiogenic molecules present are almost certainly too large to be absorbed into the blood and therefore have no effect as they are being digested rather than absorbed into the bloodstream. It is suggested that only highly purified components would be any use.
Early reports that shark cartilage cured cancer, prolonged patients’ lives or improved their quality of life were based on anecdotal evidence or uncontrolled studies. Shark cartilage was found to contain inhibitors of tumour angiogenesis. (ref 11-13) The polypeptides identified included acidic and basic fibroblast growth factor, angiogenin and transforming growth factors alpha and beta. (ref 14) Many of the formulations of commercially available shark cartilage contain little or no anti-angiogenic activity. Furthermore, not all cancers are affected by anti-angiogenic factors. Reliable dose-response data and bioavailability studies are not available.
Prevalence of use
The popularity of shark cartilage seems to have peaked between 1990 and 2000 but no data is available showing a decline in use. Reliable prevalence data are not available. In a survey including 100 patients with various types of cancer shark cartilage was among the most commonly used therapies. (ref 15) In an earlier survey including 143 advanced cancer patients, 10.7% of respondents were consuming preparations of shark cartilage (ref 16). An article in a non-peer-reviewed magazine reports that shark cartilage is a $5 billion-a-year business, with pills and powders sold in health food shops to more than 25.000 people every year. (ref 17)
Legal issues
""The FDA has not approved of the use of cartilage as a treatment for cancer or any other medical condition"
"
Shark cartilage products are marketed as dietary supplements and therefore are not submitted to medicines regulation. Pre-market evaluation and approval by the US Food and Drug Administration (FDA) are not required for dietary supplements. The FDA has not approved of the use of cartilage as a treatment for cancer or any other medical condition. Providers of dietary supplements are not legally permitted to make any claims on the packages of their products for preventing or curing any disease. In practice, such claims are, however, often made via books, websites etc.
Costs and expenditures
A typical course of shark cartilage costs approximately 525 Euros per month and the cost for approximately 100 capsules is approximately 33 Euros. (ref 2) The daily cost would be approximately 30 Euros ($40).
References
1. Lane IW. Comac L. Sharks don’t get cancer. How shark cartilage can save your life. New Your: Avery, 1992.
2. Cassileth BR Shark and bovine cartilage therapies. In: Cassileth BR, ed.: The Alternative Medicine Handbook: The Complete Reference Guide to Alternative and Complementary Therapies. New York, NY: WW Norton & Company, 1998, pp 197-200.
3. Neovastat clinical trial abstracts. Presented at the American Association for Cancer Research 92nd annual meeting. March 27, 2001.
4. 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;13:1259-63.
5. Sauder DN, Dekoven J, Champagne P, et al. Neovastat (AE-941), an inhibitor of angiogenesis: Randomized phase I/II clinical trial results in patients with plaque psoriasis. J Am Acad Dermatol 2002;47:535-41.
6. Hillman JD, Peng AT, Gilliam AC, Remick SC. Treatment of Kaposi Sarcoma with oral administration of shark cartilage in a Human Herpes virus 8-seropositive, Human Immunodeficiency Virus-Seronegative homosexual man. Arch Dermatol 2001;137:1149-52.
7. Fetrow CW, Avila JR. Professional's Handbook of Complementary & Alternative Medicines. 1st ed. Springhouse, PA: Springhouse Corp., 1999.
8. Folkman J, Long DM, Becker FF. Growth and metastasis of tumour organ culture. Cancer 1963;16:453-67.
9. Wellings SR. Neoplasia and primate vertebrate phylogeny: a review. Natl Cancer Inst Monograph 1969;31:59-128.
10. Prieur DJ, Fenstermaher JD, Guarino AM. A choroids plexus papilloma in Elasmobranchs. J Natl Cancer Inst 1976;56:1207-9.
11. Prudden J. The clinical acceleration of healing with a cartilage preparation: a controlled study. JAMA 1965;192:252.
12. Prudden JF, Balassa LL The biological activity of bovine cartilage preparations. Clinical demonstration of their potent anti-inflammatory capacity with supplementary notes on certain relevant fundamental supportive studies. Semin Arthritis Rheum 1974;3: 287-321.
13. Lee A, Langer R Shark cartilage contains inhibitors of tumor angiogenesis. Science 1983;221:1185-7.
14. Folkman J, Klagsburn M. Angiogenic factors. Science 1987;235:442-7.
15. Bernstein BJ, Grasso T. Prevalence of complementary and alternative medicine use in cancer patients. Oncology 2001;15:1267-72, 1274-5.
16. Oneschuk D, Fennell L, Hanson J, Bruera E. The use of complementary medications by cancer patients attending an outpatient pain and symptom clinic. Journal of Palliative Care 1998;14:21-6.
17. Dold C. Shark therapy. Discover 1996;4:51-7.
