Eating Shark Meat Could be Linked to Alzheimer’s Disease, Finds New Study

30 Aug 2016 --- Scientists from the University of Miami have suggested that restricting consumption of shark could have positive health benefits for consumers, after high concentrations of toxins linked to neurodegenerative diseases were found in the fins and muscles of 10 species of sharks. 

Fins and muscle tissue samples were collected from 10 shark species found in the Atlantic and Pacific Oceans for concentrations of two toxins: mercury and β-N-methylamino-L-alanine, also known as BMAA.

Deborah Mash, Professor of Neurology and senior author of the study, thinks the new research on shark meat is extremely important, explaining, "Recent studies have linked BMAA to neurodegenerative diseases such as Alzheimer's disease and amyotrophic lateral sclerosis (ALS).”

Shark products including shark fins, cartilage and meat are widely consumed in Asia and globally in Asian communities, and as a delicacy and as a source of traditional Chinese medicine. In addition, dietary supplements containing shark cartilage are consumed globally.

Researchers at the UM Rosenstiel School of Marine and Atmospheric Science and UM Miller School of Medicine 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. However, 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 the study's lead author Neil Hammerschlag, a research assistant professor at the UM Rosenstiel School and UM Abess Center for Ecosystem Science and Policy.

Scientists also found BMAA in shark fins and shark cartilage supplements. The neurotoxic methyl mercury has been known to bioaccumulate in sharks over their long lifespans.

Hammerschlag said, "People should be aware and consider restricting consumption of shark parts. Limiting the consumption of shark parts will have positive health benefits for consumers and positive conservation outcomes for sharks, many of which are threatened with extinction due in part to the growing high demand for shark fin soup and, to a lesser extent, for shark meat and cartilage products."