Cartilage is elastic, translucent connective tissue found in animals and man. Most cartilage is converted to bone as an animal matures, but some remains in such sites as the nose, ears, knees, and other joints. Cartilage extracts and supplements are made from cows (bovine cartilage), whose bodies contain both cartilage and bone, and sharks (shark cartilage), whose bodies contain cartilage and no bone.

Cartilage supplements are said to shrink tumors; to cure, or at least slow the development of, cancers; to reverse bone diseases such as osteoporosis; and to treat other conditions, such as macular degeneration and psoriasis, in which overgrowth of blood vessels causes disease symptoms.

The notion of using cartilage medicinally began in 1954, when bovine tracheal cartilage was found to promote wound healing. Since then, clinical trials have shown this substance to be effective against a broad range of conditions ranging from arthritis to cancer. In studies at the Comprehensive Medical Clinic in Southern California, patients reported pain relief in as little as three weeks, though patients should be cautioned against expecting rapid relief. Early reports claimed that sharks do not get cancer, which proved to be untrue, although it is true that the incidence of cancer in sharks is low.

Shark cartilage that has been dried and pulverized into fine powder for use as a supplement contains many active components. Among the most important is an angiogenesis inhibitor (a protein that, at least in laboratory research, suppresses the development of new blood vessels). These angiogenic effects have been demonstrated in the laboratory but have not yet been proven in human trials. Phase III clinical trials began in December 1998 on a liquid antiangiogenesis drug called Neovastat, which is made from shark cartilage. The 550 patients with small-cell lung cancer who participated were given chemotherapy; half were also given Neovastat, the other half a placebo. The joint studies are being conducted by the U.S. National Cancer Institute and a biotechnology company.

Bovine cartilage that has been cleaned, dried, and powdered to be used as a supplement helps to accelerate wound healing and reduce inflammation. Bovine tracheal cartilage was initially called catrix (from the Latin cicatrix, which refers to a healed wound). Today it is recognized as one of the few substances that speed wound healing. Both shark and bovine cartilage are beneficial for psoriasis, rheumatoid arthritis, and ulcerative colitis.

Commercially prepared supplements of bovine or shark cartilage.

Shark cartilage contains angiogenesis inhibitor proteins; approximately 16% calcium and 8% phosphorus, which are absorbed as nutrients; and immune system-stimulating mucopolysaccharides, carbohydrates that form chemical bonds with water.

Bovine cartilage is believed to inhibit tumor growth, and the polysaccharides it contains are believed to combat cancer by stimulating the immune system.

Neither shark nor bovine cartilage is U.S. FDA–approved for safety or effectiveness. (Shark cartilage was under study by the National Cancer Institute when it was discovered that every one of the cartilage supplements provided for the study had been contaminated. The trials were stopped.)

Both shark and bovine cartilage may be obtained at health stores or by mail-order as nutritional supplements. They may be purchased in powder or capsule form under a variety of brand names, typically in capsules of 750 mg.

Shark and/or bovine cartilage is used to:

• Treat arthritis
• Treat psoriasis
• Treat regional enteritis
• Relieve or reduce pain, inflammation, and joint damage associated with osteoarthritis and rheumatoid arthritis

When using shark or bovine cartilage as a dietary supplement, 3 to 4 capsules per day.

Some shark cartilage products have a strong fish odor and flavor that may be unpleasant. Taken in large doses, shark cartilage has a very unpleasant taste and often causes nausea.

With their providers' approval, most people can take shark cartilage safely as an adjunct to conventional treatments for arthritis and cancer; however, cartilage supplements should not be used in place of conventional treatments. Shark cartilage should not be used by:

• Children
• Pregnant women
• Patients who recently underwent surgery
• Patients who recently survived a heart attack

No clinically significant interactions between cartilage and conventional medications are known to have been reported in the literature to date.

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