Shark Cartilage: A Fish Supplement That Doesn’t Work?
Deep below the ocean, a razor-toothed creature lurks, waiting for the next unlucky swimmer or surfer… in other words, dinner.
That’s the premise of many a horror film, from the classic Jaws to more recent B-movies like Sharknado. It certainly doesn’t sound like the basis for a healing remedy, does it?
Yet these aquatic beasts – known not just for their killer appetite but also their speed and intelligence – have become the source of a supplement that can supposedly benefit health.
At least, that’s the claim of marketers, who swear that this product can prevent and even cure a much scarier villain: cancer.
So what’s the problem?
Well, there’s no good clinical evidence to suggest that such supplements have any benefits at all. Worse, they may cause a number of unpleasant symptoms.
No Cure for Cancer…
Scientists have recognized the possible medical value of animal cartilage since the 1950s, when New York surgeon John Prudden found that bovine (cow) cartilage appeared to help speed wound healing and shrink tumors.
Since then, cartilage from cows, pigs, sheep, chicken, and other animals has been studied for its potential in treating everything from osteoarthritis and rheumatoid arthritis to psoriasis and skin allergies.
In 1992, another type of cartilage joined these ranks following the publication of the popular book Sharks Don’t Get Cancer. In this book, I. William Lane, PhD, argues that sharks do not develop cancer, possibly due to differences in their immune system.
A year later, a television program aired a segment on patients in Cuba who allegedly went into remission from advanced cancer after taking shark cartilage.
It should come as no surprise, then, that shark cartilage was soon a hot commodity, with products flying off of store shelves.
Who wasn’t benefiting from this trend?
Well, sharks – specifically spiny dogfish and hammerhead sharks – obviously. It doesn’t really matter that these creatures supposedly don’t get cancer if they’re being slaughtered for their cartilage.
Worse, these claims were about to come back to bite proponents of shark cartilage. That’s because the product is based on a myth – and may have no health benefits at all.
A Big Fish Tale…
Here’s the real scoop: Sharks, unfortunately, do get cancer. In fact, they have been found to develop renal cell carcinoma, lymphoma, and even tumors of their cartilage.
So much for that theory.
That said, there are some intriguing findings that suggest that a certain form of shark cartilage might have some anticancer properties.
See, laboratory research has shown that shark cartilage might inhibit angiogenesis, the growth of blood vessels that feed cancerous tumors. That means it could potentially help kill cancer or at least keep it from spreading.
However, such results haven’t been replicated in clinical trials, so it’s unknown whether shark cartilage would have the same effect in people. And the human research that has been conducted isn’t so impressive.
For example, a study published in 2005 in the journal Cancer looked at the effects of powdered shark cartilage in 83 men and women with advanced cancer. They took either a placebo or up to 96 grams of shark cartilage a day, in addition to their usual cancer medications.
By the end of the study, researchers found that there were no differences in cancer survival rates between the two groups. Nor were there any improvements in quality of life. In fact, people who took shark cartilage reported an overall decrease in well-being, along with serious side effects such as dizziness, diarrhea, and bone pain.8
Other research has examined the effects of lower doses of shark cartilage in patients with breast, colorectal, lung, prostate, or brain cancer. It, too, has found no significant survival benefit for shark cartilage.1, 2, 5
And that TV program about the study of Cuban cancer patients?
Well, the findings were never published in a peer-reviewed medical journal. And the National Cancer Institute has stated that the results were “incomplete” and “unimpressive.”
This Supplement is All Wet…
Even if shark cartilage could cure cancer in the lab, there’s no way that the currently available forms of this product could be effective. That’s because the protein molecules in shark cartilage are too large to be absorbed into the digestive tract – they are excreted as waste before they even reach cancerous tumors.
That realization has led scientists to create a liquid form of shark cartilage that may be more readily absorbed. There may be something to it: One study showed that this preparation appeared to slow the growth of new blood vessels in healthy men, which suggests it might also slow the growth of tumors.6
Another study, although small and poorly designed, concluded that liquid shark cartilage might help prolong survival in people with advanced renal cell carcinoma (kidney cancer).9 But more recently, a larger study of liquid shark cartilage found no benefit for cancer patients.7
Still interested in liquid shark cartilage?
Well, don’t bother.
See, this formulation, known as AE-941, or Neovast, is only available as a medication – not a supplement. It has FDA orphan drug status, which means that is intended only for the study and treatment of rare conditions.
In other words, you won’t find AE-941 on the shelves of your local health food store.
Throw This One Back…
If the current research is any indication, powdered shark cartilage is, at best, a waste of money. But the truth is, it may not just be ineffective. It might also be harmful.
Although shark cartilage appears to be safe for most people, it can cause side effects such as nausea, vomiting, upset stomach, dizziness, low blood sugar, weakness, swelling, and fatigue. It has also been linked to signs of acute hepatitis, including elevated liver enzymes, liver pain, low-grade fever, and jaundice (yellowing of the skin and eyes).1, 2, 3
Shark cartilage also appears to increase levels of calcium in the blood, which is a problem if you also take calcium supplements or already have high calcium levels.1, 2,3
The conclusion here is clear: Shark cartilage is all washed up. Save the sharks along with your money. Don’t supplement with this useless product.
And remember, keep an open mind to new ideas, but ALWAYS do your own homework…and combine that with common sense to figure out what’s best for YOU.
6 Berbari P, Thibodeau A, Germain L, et al. Antiangiogenic effects of the oral administration of liquid cartilage extract in humans. J Surg Res. 1999 Nov;87(1):108-13.
7 Lu C, Lee JJ, Komaki R, et al. Chemoradiotherapy with or without AE-941 in stage III non-small cell lung cancer: a randomized phase III trial. J Natl Cancer Inst. 2010 Jun 16;102(12):859-65.
8 Loprinzi CL, Levitt R, Barton DL, et al. Evaluation of shark cartilage in patients with advanced cancer: a North Central Cancer Treatment Group trial. Cancer. 2005 Jul 1; 104(1):176-82.
9 Falardeau P, Champagne P, Poyet P, et al. Neovastat, a naturally occurring multifunctional antiangiogenic drug, in phase III clinical trials. Semin Oncol. 2001 Dec;28(6):620-5.
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