Shark cartilage is one of the staples among nutraceuticals, on the shelves of health food stores for quite a few years now. It is touted for its anti-inflammatory benefits in treating arthritis and other inflammatory conditions and especially, cancer.
The use of powdered cartilage to treat wounds was originally popularized by John Prudden, a surgeon from New York, in 1954. Prudden used powdered cartilage from cows, finding it effective in the acceleration of wound healing, the treatment of arthritis, inflammatory bowel disease and even advanced cancer.
Cartilage from sharks was popularized by the 1992 bestseller by William Lane and Linda Comac: “Sharks don’t get cancer”, followed by “Sharks still don’t get cancer” in 1996. The point of the claim was to imply that there is something unique about cartilage from an animal—like a shark—whose skeleton is entirely made of cartilage—not bone, and that there are curative powers which can only come from that type of animal. Of course, convincing millions of people that only shark cartilage will do is not particularly healthy for shark populations around the world, and shark populations have indeed suffered, as the commercial market for shark cartilage has skyrocketed.
Considering the fact that the original claim is erroneous—shark’s do indeed get cancer—is there any merit to the health claims about shark cartilage? I am inclined to think that there must be something to claims that seem to survive over decades in time, because enough practitioners and patients report benefits to keep the market going. So is there anything in shark cartilage that might explain the sort of beneficial actions attributed to it? To answer this question, it’s useful to look at some of the specific benefits attributed to shark cartilage. These basically boil down to three specific actions: 1) anti-inflammatory, as evidenced by benefits to patients with rheumatoid arthritis and inflammatory bowel disease; 2) the acceleration of wound healing, and 3) the ability to prevent cancer and slow the growth and spread of cancerous tumors, specifically by blocking angiogenesis, the process by which tumors grow new blood vessels to feed themselves and grow.
Clinical studies at prestigious institutions have, it turns out, failed to demonstrate any such benefits in placebo controlled scientific trials. Specifically, trials by researchers at the Mayo Clinic and the National Cancer Institute failed to find any survival benefits in patients with advanced cancer. It is difficult, however, to draw reliable conclusions from such studies, as such patients are often in very bad shape, not only because of the advanced cancer but because of toxic effects of standard drug treatments. Then again, there is the theoretical problem of attributing the putative benefits to some particular protein component of the cartilage. That’s because—as detractors are quick to point out—proteins are not absorbed whole through the GI tract; rather, they must be digested into their component amino acids first.
As it happens, the protein of shark cartilage is not only pretty much the same as cartilage from any other vertebrate, it’s pretty much the same as the protein content of bone and other connective tissues, namely, some form of the protein, collagen. Collagen from any source consists of about 22% glycine by weight, glycine being the smallest, simplest and most abundant of all the amino acids. And as I’ve been reporting on this blog, glycine is also the body’s most important regulator of inflammation. And inflammation, which is often erroneously classified as “part of the healing process”, actually impedes healing. Thus, reducing or eliminating excess inflammation accelerates healing.
So far, so good: If you eat enough shark cartilage, you might just get enough extra glycine to explain the anti-inflammatory and wound healing effects. But what about the growth of cancer, specifically, the inhibition of angiogenesis? In fact, research going back over a decade at the University of North Carolina has demonstrated the inhibition of angiogenesis and blockade of tumor growth in experimental animals by glycine. Importantly, the mechanism of action of glycine in mediating this effect and the anti-inflammatory effects is straightforward: Both macrophages (the cells that effect inflammation) and endothelial cells (cells that grow into new blood vessels) are inhibited from excess activation by appropriate concentrations of glycine.
So how much glycine is appropriate? Although it’s still generally classified as a non-essential amino acid, it’s hard for the body to make enough when we throw most of the glycine in our food away (i.e., the bones and connective tissues of meat, fish and poultry), and when the overconsumption of muscle meats makes our bodies use up glycine to get rid of other amino acids consumed in excess.
Now if you take the recommended amounts of shark cartilage in a popular supplement, i.e., up to about 4.5 grams per day of collagen (as in six 750 mg. capsules), you end up with about one gram of glycine. That’s enough to make a difference if you are severely glycine-deficient, but 8 grams per day is more like what we usually throw away, and what most bodies therefore need optimally. And for about the same price per daily serving, one stick pack of sweetamine® gives you the whole 8 grams.
My bottom line on shark cartilage is therefore that the benefits claimed for its consumption can be explained by its glycine content—if you consume enough of it. However, it’s a pretty inefficient and expensive way to get the glycine you really need to keep your immune system healthy, not to mention building your body’s own cartilage. (See my blog post: ‘World’s easiest anti-inflammatory diet’)
And one final note about sweetamine®: The glycine in it is made inorganically, because glycine is such a simple molecule Even your own liver can make it from carbon dioxide, ammonia and formaldehyde (and it has been detected even in space, on asteroids!). So you don’t have to kill any sharks, or anything else, to get all the glycine you really need to keep your diet anti-inflammatory and to keep your immune system healthy.