Toxin in Seafood Causes Kidney Damage in Mice at Levels Considered Safe for Consumption

FDA may need to reconsider what levels of domoic acid in shellfish and fish are safe

Released: 31-Jan-2014 8:00 AM EST
Embargo expired: 6-Feb-2014 5:00 PM EST
Source Newsroom: American Society of Nephrology (ASN)
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Citations Journal of the American Society of Nephrology; Download the PDF of the journal article

Highlights
• Domoic acid accumulates in seafood and is toxic to the brain
• The toxin damages kidneys at concentrations that are 100 times lower than what causes neurological effects.

Domoic acid was recognized as a human toxicant when more than 100 people became ill after eating contaminated mussels in eastern Canada in 1987.

Newswise — Washington, DC (February 6, 2014) — A chemical that can accumulate in seafood and is known to cause brain damage is also toxic to the kidneys, but at much lower concentrations. The findings, which come from a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN), suggest that officials may need to reconsider what levels of the toxin are safe for human consumption.

The world’s oceans contain algae that produce certain chemicals that can be harmful to humans and other living creatures. Many of these chemicals are considered neurotoxins because they cause damage to the brain. The neurotoxin domoic acid, also called “Amnesic Shellfish Poisoning,” is a very stable, heat resistant toxin that is becoming more prominent in coastal regions, likely due to environmental changes. It can accumulate in mussels, clams, scallops, and fish, and the FDA has set a legal limit of domoic acid in seafood based primarily on its adverse neurological effects.

Because domoic acid is cleared from the body by the kidneys, P. Darwin Bell, PhD, Jason Funk, PhD (Medical University of South Carolina), and their colleagues looked to see if the toxin might also have detrimental effects on these organs. By giving mice varying doses of domoic acid and the assessing animals’ kidney health, the team found that the kidney is much 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,” said Dr. Bell. “This means that humans who consume seafood may be at an increased risk of kidney damage possibly leading to kidney failure and dialysis.”
While the findings need to be verified in humans, the researchers would like to see increased awareness and monitoring of domoic acid levels in all seafood. They say that the FDA may also need to reconsider the legal limit of domoic acid in food due to its kidney toxicity.

Study co-authors include Michael Janech, PhD, Joshua Dillon, John Bissler, MD, and Brian Siroky, PhD.

Disclosures: John Bissler, MD receives grant funding and honoraria from Novartis and has participated in its advisory boards. This study was supported, in part, by funds from the NIH, VA, DOD, and Dialysis Clinic, Inc.

The article, entitled “Characterization of Renal Toxicity in Mice Administered the Marine Biotoxin Domoic Acid,” will appear online at http://jasn.asnjournals.org/ on February 6, 2014.

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