Canned Tuna Is Risky for Moms-to-Be, Study Finds

WASHINGTON -- The mercury levels detected in canned albacore tuna show that the popular seafood poses a risk to pregnant women and their babies, according to a study by the Mercury Policy Project.

Studies have linked fetal exposure to mercury from fish to neurological damage that can harm babies’ intelligence, coordination or memory.

In April, the Centers for Disease Control and Prevention published a study that found that 8% of women of childbearing age had concentrations of mercury in their blood higher than the dose considered safe by the Environmental Protection Agency.

The Food and Drug Administration advises women who are pregnant or may become pregnant to avoid eating the four fish highest in mercury -- shark, swordfish, king mackerel and tilefish -- and to eat no more than 12 ounces a week of a variety of other seafood.

But the study’s authors and some outside scientific reviewers said the FDA has failed to adequately warn women about the risks posed by canned albacore tuna.

“These tests confirm what FDA has known for over a decade about higher mercury levels in white tuna,” said Michael T. Bender, director of the Mercury Policy Project. “It’s time for FDA to finally tell America the truth about canned tuna.”

The canned tuna industry said that pregnant women who abide by the 12-ounce-a-week warning should not worry about mercury levels in tuna.

An FDA spokesperson said the agency has not seen the report and could not comment, but stressed that the agency stands behind its advisory.

The Mercury Policy Project, an activist group trying to reduce mercury emissions, commissioned laboratories to study tuna sampled from 48 cans of white, or albacore, tuna and 12 cans of light tuna.

Three albacore samples contained mercury levels higher than 1 part per million, the level of contamination at which the FDA may deem food adulterated. The average mercury level in all the albacore cans was 0.51 ppm. The light tuna samples had only a quarter of that much mercury, 0.12 ppm.

An analysis by the report’s authors found that eating just one six-ounce can of white tuna with 0.5 ppm of mercury could give a woman of childbearing age a dose of mercury two times greater than the level deemed safe by the EPA.

Alan Stern, adjunct associate professor at the University of Medicine and Dentistry of New Jersey’s School of Public Health, was one of several scientists who reviewed the study. He said he considers the report “scientifically defensible” and agreed with its authors that women who are pregnant, nursing or may get pregnant should limit or stop eating albacore tuna.

But David Burney, executive director of the U.S. Tuna Foundation, which represents the canned tuna industry, challenged the scientific validity of the study and disagreed with its basic findings.

“If you follow FDA consumption advice, limiting [tuna consumption] to 12 ounces per week, there is absolutely no danger to a pregnant woman from eating canned tuna,” Burney said.

Burney did not dispute that albacore contains more mercury than light tuna. As a general rule, the larger the fish, the higher the mercury levels, and albacore tuna are larger than skipjack tuna, the variety that goes into canned light tuna.

But the industry regularly tests tuna to ensure that there is no increase in mercury levels in the fish, and the amount of mercury detected in albacore tuna continues to be “significantly below” 1 ppm, the level the FDA uses as a threshold for regulatory action, he added.

Burney said the big news about mercury in fish was a nine-year study by the University of Rochester Medical Center published in May in Lancet, a British medical journal. The study tracked children exposed to mercury in utero from mothers who ate an average of 12 servings of fish a week in the Seychelles, an island country in the Indian Ocean. The researchers, who investigated 779 mother-infant pairs, found that their data did not support the hypothesis that there is a neurodevelopmental risk from prenatal exposure to mercury from ocean fish.

But Stern stressed that other valid studies have found a clear link between mothers eating fish tainted with mercury and neurological problems in their offspring.

Several states, including California, already warn pregnant women to limit the amount of canned tuna they eat.