Cartilage is a tough connective tissue found in many parts of the body. Your ears and nose are made from cartilage, and so is the gliding surface in your joints. One constituent of cartilage, chondroitin, is widely used in Europe to treat arthritis. Cartilage itself has also been proposed as a treatment for arthritis. The most commonly used forms of cartilage come from cows (bovine cartilage) and sharks. Provocative evidence suggests that shark cartilage might have some value in the treatment of cancer. However, properly designed studies have not yet been completed to tell us whether it really works. -------------------------------------------------------------------------------- Sources Unless your uncle works at a slaughterhouse or you're brave enough to prepare your own cartilage from whole sharks, the preferred source of cartilage is your health food store or pharmacy, where you can purchase this supplement in pill or powdered form. -------------------------------------------------------------------------------- Therapeutic Dosages Various doses of cartilage have been used in different studies, ranging from 2.5 mg to 60 g daily. -------------------------------------------------------------------------------- Therapeutic Uses Based on the belief that sharks don't get cancer, shark cartilage has been heavily marketed as a cure for cancer. While this is a myth (sharks do get cancer), shark cartilage has, in fact, shown some promise. Shark cartilage tends to inhibit the growth of new blood vessels (angiogenesis). Since cancers must build new blood vessels to feed themselves, this effect might be beneficial. Double-blind studies on shark cartilage for cancer are now underway. Shark cartilage also inhibits substances called matrix metalloproteases (MMPs).1 These little-understood enzymes affect the "extracellular matrix," the framework of substances that lie between cells in the body. MMPs are thought to play a role in diseases of the cornea, gums, skin, blood vessels, and joints, as well as cancer and illnesses that involve excessive fibrous tissue. Weak evidence suggests that shark cartilage might be helpful for psoriasis.2 Cartilage in general has been proposed as a treatment for the common "wear and tear" type of arthritis known as osteoarthritis. The idea behind this is straightforward: Because osteoarthritis is a disease of the joints, and because cartilage is one of the elements that make up your joints, adding cartilage to the diet might help. This idea sounds a bit too simplistic to be real, but it is the same principle behind the use of glucosamine and chondroitin (specific substances found in the joints) for osteoarthritis. Since double-blind studies have found those treatments effective, perhaps cartilage itself will ultimately be proven to work. However, studies of cartilage have not yet been performed. Highly preliminary studies suggest cartilage may help heal minor wounds.3 -------------------------------------------------------------------------------- What Is the Scientific Evidence for Cartilage? A number of test tube experiments have found that shark cartilage extracts prevent new blood vessels from forming in chick embryos and other test systems.4–9As mentioned above, this effect could conceivably mean that shark cartilage might fight cancer. These findings have led to other test tube experiments, animal studies, and preliminary human trials to investigate the possible anticancer effects of shark cartilage. The results suggest that a particular liquid shark cartilage extract might be useful in the treatment of various cancers, including lung, prostate and breast cancer.10–15 However, not all studies have been positive.16,17 Double-blind trials are needed to provide conclusive data. These are now underway in the United States and Canada. -------------------------------------------------------------------------------- Safety Issues Because cartilage is just common, ordinary gristle, it is presumably safe to consume. However, for reasons that are not at all clear at this time, there is a report of an individual who developed liver inflammation after taking shark cartilage supplements.18 He recovered fully when the supplements were discontinued. -------------------------------------------------------------------------------- References 1. Wojtowicz-Praga S. Clinical potential of matrix metalloprotease inhibitors. Drugs R D (New Zealand). 1999;1:117–129. 2. Dupont E, Savard PE, Jourdain C, et al. Antiangiogenic properties of a novel shark cartilage extract: Potential role in the treatment of psoriasis. J Cutan Med Surg. 1998;2:146–152. 3. Prudden JF, Nishihara G, Baker L. The acceleration of wound healing with cartilage-I. Surg Gynecol Obstet. 1957;105:283–287. 4. Dupont E, Savard PE, Jourdain C, et al. Antiangiogenic properties of a novel shark cartilage extract: Potential role in the treatment of psoriasis. J Cutan Med Surg. 1998;2:146–152. 5. Sheu JR, Fu CC, Tsai ML, et al. Effect of U-995, a potent shark cartilage-derived angiogenesis inhibitor, on anti-angiogenesis and anti-tumor activities. Anticancer Res. 1998;18:4435–4441. 6. Davis PF, He Y, Furneaux RH, et al. Inhibition of angiogenesis by oral ingestion of powdered shark cartilage in a rat model. Microvasc Res. 1997;54:178–182. 7. Oikawa T, Ashino-Fuse H, Shimamura M, et al. A novel angiogenic inhibitor derived from Japanese shark cartilage (I). Extraction and estimation of inhibitory activities toward tumor and embryonic angiogenesis. Cancer Lett. 1990;51:181–186. 8. McGuire TR, Kazakoff PW, Hoie EB, et al. Antiproliferative activity of shark cartilage with and without tumor necrosis factor-alpha in human umbilical vein endothelium. Pharmacotherapy. 1996;16:237–244. 9. Lee A, Langer R. Shark cartilage contains inhibitors of tumor angiogenesis. Science. 1983;221:1185–1187. 10. Riviere M, Latreille J, Falardeau P, et al. AE-941 (Neovastat), an inhibitor of angiogenesis: phase I/II cancer clinical trial results. Cancer Invest. 1999;17(suppl 1):16–17. 11. Jamali M-A, Riviere M, Falardeau P, et al. Effect of AE-941 (neovastat), an angiogenesis inhibitor, in the Lewis lung carcinoma metastatic model, efficacy, toxicity prevention and survival. Clin Invest Med. 1998;(suppl):S16. 12. Riviere M, Falardeau P, Latreille J, et al. Phase I/II lung cancer clinical trial results with AE-941 (neovastat), an inhibitor of angiogenesis. Clin Invest Med. 1998;(suppl):S14. 13. Riviere M, Alaoui-Jamali M, Falardeau P, et al. Neovastat: an inhibitor of angiogenesis with anti-cancer activity. Presented at: American Association for Cancer Research Annual Meeting 39; March 28–April 1, 1998; New Orleans, La. 14. Blasecki J, Alaoui-Jamali M, Wang T, et al. Oral administration of Neovastat inhibits tumor progression in animal models of progressive tumor growth and metastasis. Int J Oncol. 1997;11(suppl):934. 15. Dupont E, Alaoui-Jamali M, Wang T, et al. Angiostatic and antitumoral activity of AE-941 (Neovastat), a molecular fraction derived from shark cartilage. Presented at: American Association for Cancer Research Annual Meeting 38; April 12–16, 1997; San Diego, Calif. 16. Horsman MR, Alsner J, Overgaard J. The effect of shark cartilage extracts on the growth and metastatic spread of the SCCVII carcinoma. Acta Oncol. 1998;37:441–445. 17. Miller DR, Anderson GT, Stark JJ, et al. 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. 18. Ashar B, Vargo E. Shark cartilage–induced hepatitis. Ann Intern Med. 1996;125:780–781. |
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