Vitamins, Minerals and Dietary Supplements
What is shark cartilage? Why do we need it?
Shark cartilage comes, surprisingly enough, from the bodies of sharks - in particular, the hammerhead shark and the spiny dogfish shark. It is dried, cleaned, then pulverized into a powder before being used. Shark cartilage should not confused with bovine cartilage, which may contain different constituents and have different properties.
The main ingredients in shark cartilage are angiogenesis inhibitor proteins, along with calcium, phosphorus, and immune system-stimulating mucopolysaccharides. These angiogenesis inhibitor proteins have been shown in in vitro and animal studies to help shrink the growth of cancerous tumors by preventing them from developing new blood vessels, and to reduce the effects of macular degeneration. However, these trials have yet to be conducted in humans. Shark cartilage may also help treat conditions such as glaucoma, osteoarthritis, osteoporosis and psoriasis, and facilitate wound healing.
How much shark cartilage should I take?
When using shark cartilage as a dietary supplement, some practitioners recommend that patients take between 3 and 4 capsules per day, in the dosage of 750 milligrams per capsule. The dosage may be increased to treat other conditions, but patients should consult with a licensed health care provider before taking large amounts of shark cartilage.
What forms of shark cartilage are available?
Shark cartilage can be found at some health food stores, and may be available by mail order as a nutritional supplement. It is usually available as a powder, capsule, or tablet. However, most over-the-counter forms of shark cartilage contain binding agents or fillers, and have little to no active ingredients. Some companies are in the process of creating concentrated shark cartilage extracts, but these are not yet available for public consumption.
What can happen if I take too much shark cartilage? Are there any interactions I should be aware of? What precautions should I take?
Shark cartilage typically has a strong fish odor and/or flavor, which may be unpleasant. Among the side-effects associated with shark cartilage are nausea, vomiting, constipation and diarrhea. Children, pregnant women, patients who recently have undergone surgery, patients who recently survived a heart attack, patients with liver disease, and patients with shellfish allergies should all avoid the use of shark cartilage. Chronic use of large quantities of shark cartilage may also interfere with a person's ability to metabolize magnesium and potassium; as a result, people may need to take extra doses of these nutrients to maintain proper mineral levels.
As of this writing, there are no known drug interactions with shark cartilage. As always, make sure to consult with a licensed health care provider before taking shark cartilage or any other dietary supplement or herbal remedy.
- Davis PF, et al. Inhibition of angiogenesis by oral ingestion of powdered shark cartilage in a rat model. Microvasc Res 1997;54:178-82.
- 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.
- 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;37:441-5.
- 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.
- Murray M. Encyclopedia of Nutritional Supplements. Rocklin, CA: Prima Publishing, 1996.