From guest blogger Nirvi Shah:
Children should eat light tuna no more than once or twice a month, depending on their size, and they should never eat albacore tuna, to reduce their exposure to mercury, a research and advocacy group said today.
These limits should encompass all of children's meals, at school and home, a new report from the Vermont-based Mercury Policy Project says.
The problem with too much mercury: impairment of cognitive thinking, memory, attention, language, and fine-motor and visual spatial skills. While most research has focused on these effects of mercury on developing fetuses, the Mercury Policy Project said mercury can have the same effects on children's still-developing brains.
"The question is not tuna or no tuna, it's how often," said Ned Groth, a consultant scientist with the group and the author of the report. "The risk is perfectly acceptable if [children's] intake is low."
Schools have been buying less tuna to serve in school meals—in the 2010-11 school year, schools in the National School Lunch Program bought 6 million pounds of tuna, down from 10 million pounds in 2008. But as schools work toward new school meal requirements that call for lower-calorie, more-healthful meals, tuna may become more appealing because it is a low-fat source of protein, said Sarah Klein, a staff attorney with the Food Safety Program at the Center for Science in the Public Interest in Washington.
The U.S. Department of Agriculture, which operates the school lunch and breakfast programs, said that it no longer buys tuna for any of its nutrition programs because there isn't a domestic supplier of the product, although schools can buy tuna on their own.
In a recent survey of school food directors, the School Nutrition Association asked about the most popular lunch and breakfast choices in schools and tuna was not on the list, and sandwiches or wraps—where tuna would be most likely to appear—was the most popular lunch entrée in only 1.1 percent of responding districts. Pizza, chicken, beef, pasta, and Mexican dishes are the leading favorites, with pizza registering as the most popular item by a wide margin.
As part of its research, the Mercury Policy Project tested some of the tuna available in schools and found that mercury levels varied from brand to brand and within a single large can of tuna, which may contain a mix of fish from different places. That led to the recommendations that children who weigh 55 pounds or less should not eat light tuna more than once a month and larger children should eat it no more than twice a month, Groth said. Children should never eat tuna every day. And kids of all sizes should never eat albacore tuna, which can have triple the mercury of light tuna, Groth said.
He noted that as the organization searched for samples to test, some school districts could not participate because tuna isn't on their menus.
Mercury gets into the oceans from the burning of coal, volcanic eruptions, and erosion. It's converted by bacteria to methylmercury, and this substance accumulates in animals who eat the fish and animals who consume this bacteria. So tuna are among the larger creatures in which mercury collects. For children who like tuna, salmon, shrimp, and sardines can be offered as alternatives, Groth said.
The Food and Drug Administration is in the midst of reviewing its guidelines about acceptable mercury exposure, he said. The current guidelines, created with the U.S. Environmental Protection Agency, date back to 2004.