The bad science: Shark cartilage as a cancer therapy

What do they claim? They claim shark cartilage can prevent or cure cancer.

Are they trying to sell you something?  Of course, and it’s not cheap.

Is any of this true? The suggestion that shark cartilage could cure or prevent cancer seems to have originated from the belief that sharks don’t get cancer at all.  There are two things wrong with this:  First, just because another organism has a biological or physiologic attribute that we as humans may admire, this does not mean that EATING that organism will confer upon you or I these attributes. Here are some examples:

1. Eating lots of turkey will not allow a human to fly (yes, turkeys can fly, albeit poorly)
2. Eating an owl will not give you night vision or allow you to turn your head all the way around Exorcist-style.
3. No matter how many plants you eat, your body will never produce chlorophyll allowing you to make your own energy from the sun.

The second problem is that sharks totally get cancer.  Especially skin cancer.  Don’t believe me?  <–Here’s a photo.  There aren’t many animals that don’t get cancer.  The one that most people seem to agree upon is the naked mole rat.  You don’t see many people running out to eat the cartilage of the naked mole rat, and for good reason.  This is absurd and would be cruel to mole rats. They are tiny, so you won’t get much cartilage form them. Plus they are ugly and not “cool” like sharks. We all want to be just a little bit like sharks, the apex predator of the sea. No one wants to look like this —>.

Cartilage is made up mainly of protein and simple carbohydrates.  It’s tough, but when exposed to the acid environment of your stomach, it will be digested to it’s component parts – amino acids and simple sugars.  These are not likely to help your fight against cancer more than your average turkey sandwich.

Shark cartilage is also sold for the treatment of arthritis and joint pain. The theory here seems to be that you can replace the missing components of your cartilage or lubricate the joints more effectively by taking this supplement.  This same theory has led millions of people to take glucosamine and chondrodin supplements.  Both glucosamine and chondrodin are components of cartilage, so supplementing with them must help heal your joints, right?  Unfortunately, there is no clear evidence that these wildly popular supplements work to reduce joint pain or improve joint structure/function.

Is any of this Dangerous? This is obviously dangerous for sharks, but taking shark cartilage for cancer is dangerous for people too.  It’s not dangerous because it’s toxic – there are no reports of serious shark cartilage-related adverse effects.  You could probably gnaw on a shark fin for days on end and be just fine (unless it’s attached to a shark!).  It’s dangerous because it could be seen by patients as an effective treatment and used to justify foregoing aggressive conventional cancer treatment.  The most famous case of this is that of Steve Jobs.  Jobs was a visionary, but when diagnosed with what is generally a treatable form of pancreatic cancer he spent months self-medicating with a juice diet, acupuncture, and spiritual therapy.  By the time he sought more conventional treatments, the cancer had metastasized and Jobs died shortly thereafter.  We will never know if Jobs would have survived if he had followed the recommended treatment strategy form the start.  However, one thing we do know is that if all cancer patients delayed their cancer treatment by several months to pursue such clearly bogus treatments, the rate of cancer deaths would surely increase.  Don’t try to treat cancer with shark cartilage, or any other kind of cartilage.  It won’t work.

The use of shark cartilage for arthritis and similar conditions carries very little risk to humans – these are not life-threatening diseases after all.  The downside here is that you’re contributing to the decline of shark species throughout the worlds oceans, just like those buying shark fin soup.  That’s just not cool. Even Yao Ming says so.

What’s the bottom line?  Shark cartilage won’t cure or prevent cancer.  If you or someone you know has cancer – see a doctor and take it seriously.   If you have arthritis and really want to take an unproven supplement for your joint pain, just buy some chondrodin and glucosamine.   They are cheaper, and they don’t kill sharks.