Eating shark meat may put you at Alzheimer's risk

Shark products, including meat, fins and cartilage, which are widely consumed in Asia, may put you at risk of Alzheimer's disease, say scientists who found high concentrations of toxins linked to neurodegenerative diseases in the fins and muscles of 10 species.
Scientists at University of Miami (UM) suggest that restricting consumption of sharks can have positive health benefits for consumers and for shark conservation, since several of the sharks analysed in the study are threatened with extinction due to overfishing.
Fins and muscle tissue samples were collected from 10 shark species found in the Atlantic and Pacific Oceans for concentrations of two toxins - beta-N-methylamino-L-alanine (BMAA) and mercury.

"Recent studies have linked BMAA to neurodegenerative diseases such as Alzheimer's disease and amyotrophic lateral sclerosis (ALS)," said UM professor Deborah Mash.
Researchers detected concentrations of mercury and BMAA in the fins and muscles of all shark species at levels that may pose a threat to human health.
While both mercury and BMAA by themselves pose a health risk, together they may also have synergistic toxic impacts.

"Since sharks are predators, living higher up in the food web, their tissues tend to accumulate and concentrate toxins, which may not only pose a threat to shark health, but also put human consumers of shark parts at a health risk," said Neil Hammerschlag, UM research assistant professor.

Shark products including shark fins, cartilage and meat are widely consumed in Asia and globally in Asian communities, as a delicacy and as a source of traditional Chinese medicine.
In addition, dietary supplements containing shark cartilage are consumed globally.
About 16 per cent of the world's shark species are threatened with extinction.
The shark species sampled in this study range in threat status from least concern (bonnethead shark) to endangered (great hammerhead) by the International Union for Conservation of Nature (IUCN).
"Our results suggest that humans who consume shark parts may be at a risk for developing neurological diseases," said Mash.

The study was published in the journal Toxins.