General Description
Unlike other animals, the skeleton of sharks is composed almost
entirely of cartilage. Shark cartilage contains many of the same
compounds that make up human cartilage, including proteins, chondroitin
sulfate, calcium, phosphorus, and hyaluronic acid. Shark cartilage
supplements are derived from the skeletons of sharks that are caught
for food purposes.
Health applications
Cancer
Due largely to the publication of a book entitled Sharks Don't Get
Cancer, by I. William Lane, PhD, an increasing number of people
are using shark cartilage as an alternative cancer therapy. This
therapy is based on the fact that, in order to grow, tumors depend
on the formation of new blood vessels to feed them.1
The process of new blood vessel formation is called angiogenesis.
Advocates of cartilage therapy cite laboratory studies which indicate
that some compounds in shark cartilage inhibit angiogenesis.2-4
However, the efficacy of cartilage as a cancer treatment has not
been established, and preliminary studies on shark cartilage have
shown no effect on tumor growth. 5,6 Further
studies, sponsored by the National Cancer Institute (NCI) and the
National Center for Complementary and Alternative Medicine (NCCAM),
are planned.7 Arthritis
Because shark cartilage contains many of the same natural compounds
that make up human joint cartilage, shark cartilage supplements
are used by many arthritis sufferers hoping to replenish deteriorated
joint tissues. Although some studies indicate that shark cartilage
may exhibit analgesic and antiinflammatory activity,8,9
shark cartilage use in the treatment of arthritis has little scientific
support.
Dosage/Toxicity
Shark cartilage is commonly taken in doses of 3,000 to 5,000 mg
per day, and is generally well tolerated at this dosage range.
Some people may experience nausea when taking larger doses. Although
shark cartilage has no known toxicity, because of its high calcium
content, daily intake should not exceed 50 grams. |
