Shark cartilage is a popular dietary supplement for the treatment of cancer and for the prevention or treatment of a number of other illnesses.
You, like I, might reasonably ask why in the world anyone would ever think that shark cartilage would combat cancer — or any other disorder, for that matter.
The use of shark cartilage as an alternative medication was popularized by the 1992 publication of the book "Sharks Don't Get Cancer" by Dr. William Lane.
Their failure to get cancer was presumed to be due to the large amount of cartilage in their bodies. The potential benefits of shark cartilage are supported by stories told of its effectiveness by users and by some test-tube experiments.
Responding to demands of consumers, in 1998 Congress mandated studies of the therapeutic value of shark cartilage in the treatment of cancer.
In 2005, a publication in the journal Cancer reported the results of a public-health-sponsored, randomized, placebo-controlled trial from the Mayo Clinic. Data on 83 patients with incurable breast or colorectal cancer revealed no differences in overall survival or improvements in quality of life between those taking shark cartilage or a placebo.
The results of another clinical trial, sponsored by the National Cancer Institute, on 379 patients were reported at the June 2007 meeting of the American Society for Clinical Investigation. Patients with advanced non-small-cell lung cancer were randomly assigned to receive either a placebo or an extract of dogfish shark cartilage. There were no differences between the two groups in survival; in fact, survival was slightly worse in those taking the shark cartilage. The Canadian manufacturer stopped its production of the shark-cartilage extract in March, presumably because the company had received early notification of this trial's outcome.
Though these carefully conducted clinical trials should dispel any notion that shark cartilage is useful for fighting cancer, promotions for its sale to unwary consumers will undoubtedly continue.
And, last, here's one more possible blow to the utility of shark cartilage against cancer: At least 42 varieties of cancer have been discovered over the past 5 years in sharks and related species.
