Shark cartilage, which has been hyped as a cancer preventive and joint-health supplement, may contain a neurotoxin that has been linked with Alzheimer’s and Lou Gehrig’s disease.
Scientists at the University of Miami analyzed cartilage samples collected from seven species of sharks off the coast of Florida. The specimens all contained high levels of a compound called beta-methylamino-L-alanine, or BMAA, which has been linked to the development of neurodegenerative diseases. Sharks accumulate the compound because of their status at the top of the oceanic food chain, consuming fish and other sea creatures that feed on BMAA-containing algae. The small tissue samples were obtained from sharks that were caught, tagged and released for tracking research, and no sharks were harmed for the study.
The findings are important because of the growing popularity of supplements that contain cartilage from shark fins. The products are widely sold and remain popular with consumers who view them as cancer fighters or as a remedy for joint and bone problems. The notion that shark cartilage can prevent cancer grew largely from the popularity of the 1992 book “Sharks Don’t Get Cancer.”
Although a number of studies have discredited shark cartilage as a cancer fighter, supplement makers have nonetheless made bold claims. In 2000, two supplement makers settled a federal suit as a result of hyping shark cartilage and paid restitution to customers.
Although the Miami scientists didn’t examine shark cartilage supplements directly, their findings add further cause for concern about the popularity of shark fin supplements. In the study, published in the journal Marine Drugs, the researchers found levels of BMAA ranging from 144 to 1,836 nanograms per milligram of cartilage in seven shark species, including hammerhead, blacknose, nurse and bull sharks. The toxin initially is produced by bacteria in large algae blooms that are brought on by agricultural runoff and sewage pollution.
Earlier studies have suggested that BMAA may be common in the brains of people with degenerative diseases. One in 2009, for example, found that brain samples from people who died of Alzheimer’s or Lou Gehrig’s disease had BMAA levels as high as 256 ng/mg. The brains of control subjects who died of other causes had only trace amounts or none at all. While BMAA has never been definitively cited as a cause of degenerative diseases in humans, some scientists hypothesize that it may be a contributing factor.
Scientists at the University of Miami analyzed cartilage samples collected from seven species of sharks off the coast of Florida. The specimens all contained high levels of a compound called beta-methylamino-L-alanine, or BMAA, which has been linked to the development of neurodegenerative diseases. Sharks accumulate the compound because of their status at the top of the oceanic food chain, consuming fish and other sea creatures that feed on BMAA-containing algae. The small tissue samples were obtained from sharks that were caught, tagged and released for tracking research, and no sharks were harmed for the study.The findings are important because of the growing popularity of supplements that contain cartilage from shark fins. The products are widely sold and remain popular with consumers who view them as cancer fighters or as a remedy for joint and bone problems. The notion that shark cartilage can prevent cancer grew largely from the popularity of the 1992 book “Sharks Don’t Get Cancer.”
Although a number of studies have discredited shark cartilage as a cancer fighter, supplement makers have nonetheless made bold claims. In 2000, two supplement makers settled a federal suit as a result of hyping shark cartilage and paid restitution to customers.
Although the Miami scientists didn’t examine shark cartilage supplements directly, their findings add further cause for concern about the popularity of shark fin supplements. In the study, published in the journal Marine Drugs, the researchers found levels of BMAA ranging from 144 to 1,836 nanograms per milligram of cartilage in seven shark species, including hammerhead, blacknose, nurse and bull sharks. The toxin initially is produced by bacteria in large algae blooms that are brought on by agricultural runoff and sewage pollution.
Earlier studies have suggested that BMAA may be common in the brains of people with degenerative diseases. One in 2009, for example, found that brain samples from people who died of Alzheimer’s or Lou Gehrig’s disease had BMAA levels as high as 256 ng/mg. The brains of control subjects who died of other causes had only trace amounts or none at all. While BMAA has never been definitively cited as a cause of degenerative diseases in humans, some scientists hypothesize that it may be a contributing factor.
by Anahad O'Connor, NY Times | Read more:
Barbara Walton/European Pressphoto Agency
