Shark cartilage side effects have hit the medical research world this week with a startling tale of toxic contamination. Glucosamine and chondoitin work well based on numerous objective MRI studies to help cartilage in many patients. One common source of these cartilage components is cartilage taken from sharks. Since sharks are sharks, there’s something gratifying about their use in a supplement, as who wouldn’t want to be on the other side of the shark-man equation? However, mercury contamination in shark fins has been seen for years. How about shark cartilage supplements? Turns out almost all of them are contaminated with not only mercury, but also a nasty neurotoxin known as BMMA which makes the mercury more toxic!
Mercury is a nervous system toxin that can cause birth defects and changes in IQ as well as cardiovascular and immune system dysfunction. It tends to be found in the highest concentrations in fish that are higher up on the food chain, like sharks. The fish lower down on the food chain concentrate it in their fat and then sharks eat those fish and further concentrate the toxin. BMMA is a neurotoxin produced by certain types of marine bacteria. The biggest issue with mercury and BMMA is that they are a dangerous synergistic tag team. When either is present in concentrations that wouldn’t normally cause toxicity to the central nervous system, BMMA can cause the lower concentration of mercury to become toxic by depleting a critical cellular defense chemical (the antioxidant glutathione).
This new study looked at 16 popular brands of shark cartilage. They used very sophisticated analytical lab tests to determine mercury and BMMA levels. The study detected 86-265 micrograms of mercury per gram of shark cartilage. Let’s look closer at this amount. The Europeans consider safe mercury intake to be 1.3 micrograms per kilogram of body weight per week. So a woman weighing in at 110 pounds would be 50 kilograms and a large man would be 100 kilograms. The safe levels then for our 50 Kg woman would be 65 micrograms per week. Shark cartilage is commonly taken at 1,500 mg per day. This means that if our 110 pound woman took the brand with the lowest mercury contamination, she would be getting exposed to about 15 times the maximum allowed levels of mercury (903 micrograms)!
The upshot? Avoid shark cartilage as a source of glucosamine and chondoitin! There’s just no reason to expose yourself to these toxins when there are so many other sources for these supplements.