Shark Cartilage Project:
This projecty falls under SHARKLIFE AIM No. 2: Reduce anthropogenic threats to over exploited marine species by increasing awareness and encouraging sustainable seafood choices.
Annually an estimated 100million sharks are harvested for cartilage, liver oil and other products (2). Shark cartilage is primarily used in shark fin soup, an expensive traditional delicacy served in many Asian countries. Shark cartilage is also a source of Chondroitin Sulfate (CS), a main ingredient in osteoarthritic supplements traded on the nutraceutical market. CS is also sourced from beef (bovine), pork (porcine), chicken (avian), and other mammalians (1).
Osteoarthritis is a disease affecting the joints of humans and animals, characterized by the cracking and reduction of cartilage within the joints resulting in chronic pain and the loss of mobility. It is most commonly caused by the excessive use of the joint, strong physical impacts (trauma) and general aging.(4)
While it is scientifically substantiated that CS extracted from bovine, porcine, avian and mammalian sources have therapeutic effects on osteoarthritic symptoms (7), the ingestion of shark cartilage (CS) provides greatly reduced benefits to sufferers of degenerative joint disease (1). This is due to the molecular properties of CS, which differ vastly between sources. Bovine sourced CS has the lowest molecular weight (7-21 kDa in its most refined form) and thus has the highest bioavailability, or is the most digestible form of CS, while CS sourced from shark has the largest molecular weight (+40 kDa in its most refined state) (4). This means Shark CS has a poor bioavailability to mammals (including humans) as the large CS molecule does not pass efficiently through the intestinal wall. Instead of being absorbed into the body, Shark CS is mostly broken down and excreted, limiting the therapeutic effects on affected joints (5;6). Not only does it have limited medicinal benefits, the long term risks of ingesting shark cartilage are not yet conclusive (9).
It is important to reiterate that shark cartilage supplements are only traded on the nutraceutical market (not pharmaceutical) which is not regulated by the Food and Drug Administration (FDA) or similar body, meaning suppliers do not need to validate a products performance with clinical tests as in the pharmaceutical industry.(4)
The poor management of shark fisheries worldwide means many species are over-fished and are becoming increasingly threatened with extinction. Of the 1,041 known species of cartilaginous fishes (sharks, rays) more than 25 percent are endangered, threatened, vulnerable to extinction or near threatened (8). Healthy shark populations are vital to maintaining biodiversity and the population levels of numerous other marine species (2;1).
Sharklife aims to better inform the public of the poor performance of shark cartilage supplements and reduce the needless consumption of shark sourced CS within South Africa.
(1) Hepplestone, Dr. L.M. BCSc, n.d., Use of Shark Cartilage in Osteoarthritic Nutraceuticals.
(2) Hepplestone, Dr. L.M. BCSc, 2008, Shark Cartilage in Osteoarthritic Nutraceuliticals - Trade Statistics.
(3) The Shark Trust, Nigel Hulbert n.d., Shark Cartilage.
(4) Hepplestone, Dr. L.M. BCSc, 2008, Osteoarthritis, Blue Hills Veterinary Hospital.
(5) Volpi, N., 2002, Oral bioavailability of chondroitin sulphate (Condrosulf) and it’s constituents in healthy male volunteers. Osteoarthritis Cartilage; 10:768-777.
(6) Volpi, N., 2003, Oral absorption and bioavailability of ichthyic origin chondroitin sulphate in healthy male volunteers. Osteoarthritis Cartilage; 11:433-441.
(7) Neil, Kirsten M., Caron, John P., Orth, Michael W., 2005, The role of glucosamine and chondroitin sulphate in treatment for and prevention of osteoarthritis in animals. JAVMA, Vl 226, No.7.
(8) IUCN Red List, 2014, Assessment Results - Extinction Risk & Conservation of the World’s Sharks & Rays, Analysis from the IUCN Shark Specialist Group.
(9) D.Uebelhart, M.D., 2008, Clinical review of chondroitin sulfate in osteoarthritis, Osteoarthritis and Cartilage, Volume 16, Supplement 3, October 2008, Pages S19-S21.