Neurotoxin in Seafood Causes Kidney Damage at Levels FDA Considers Safe

A chemical found in seafood is known to cause brain damage, but a recent study found that the toxin is damaging to the kidneys at much lower concentrations. The findings, appearing in an upcoming issue of Journal of the American Society of Nephrology, suggest that officials may need to reconsider what levels of the toxin are safe for human consumption.

Likely due to environmental changes, domoic acid, a neurotoxin also called "Amnesic Shellfish Poisoning," is becoming prominent among algae along coastal regions. The stable, heat resistant toxin accumulates in mussels, clams, scallops and fish, which led the FDA to set a legal limit on the amount of domoic acid allowed in seafood, based primarily on its neurological effects.

Domoic acid is filtered from the body by the kidneys, a fact that led P. Darwin Bell and Jason Funk of the Medical University of South Carolina to measure the toxins effects on those organs. By giving mice doses of domoic acid, the team found the kidneys are more sensitive to this toxin than the brain.

"We have found that domoic acid damages kidneys at concentrations that are 100 times lower than what causes neurological effects," Bell said. "This means that humans who consume seafood may be at an increased risk of kidney damage possibly leading to kidney failure and dialysis."

While human testing will be needed to verify the findings, the researchers are hopeful they will see an increased awareness and monitoring of domoic acid levels in seafood sold to humans, according to a statement. They said the FDA may need to reconsider the legal limit, as it is based on levels harmful to the brain.