Published By CBS News:
Diners these days are confused: They’re encouraged to eat fish for their health, but it seems like the news is full of stories about the potential dangers of seafood. With so much conflicting information, it’s hard to know what to make for dinner.
Dr. Mallika Marshall dropped by The Saturday Early Show to help separate fact from fiction.
Americans eat an astounding 1 billion pounds of canned tuna per year; it’s our most popular fish.
Tuna has “become a staple in the American diet. Who doesn’t love a basic tuna fish sandwich?†asks Marshall. “And now sushi has become one of our favorite ethnic foods, with hamachi or raw tuna being a big part of that cuisine. Also, seared ahi tuna is on many restaurant menus.â€
But mercury is present in our water supply, and fish absorb the mercury, she points out. “The mercury is both naturally occurring in the environment and used in farming and manufacturing,†said Marshall. “Almost every type of fish contains some level of mercury, and larger fish, like tuna, contain higher amounts than other types. So because tuna is eaten in such large amounts by Americans and because it contains moderate levels of mercury … it can pose a risk for some people.â€
For most of us, the level of mercury absorbed by normal consumption of tuna sandwiches or the occasional sushi dinner will cause no harm.
â€But for a developing fetus or for young children, exposure to significant levels of mercury can lead to severe nerve and brain damage as well as milder intellectual, motor and psychosocial development. So it’s the developing fetus in a pregnant woman and young children that we’re most concerned with,†says Marshall.
Is there any kind of tuna that’s less potentially harmful? Marshall says light canned tuna has the lowest levels of mercury. “That’s because canned light tuna tends to be the meat of smaller tuna … and smaller fish tend to have lower levels of mercury,†she says.
â€Albacore tuna comes from larger tuna which accumulate more mercury in ocean waters, so canned albacore tuna is higher in mercury than light. And tuna steaks and tuna used for sushi tends to have the highest levels of mercury because they also come from large tuna.â€
The way that tuna is prepared -cooked, raw, or marinated- has no effect on the level of mercury.
There are some fish that seem to have lower levels of mercury: tilapia, mahi mahi, flounder, shrimp, salmon, pollock and catfish, for example.
If you must have tuna, how much is safe to eat? According to Marshall, “For men, non-pregnant or lactating women, and older children … it’s generally recommended that they get at least 2-3 servings of fish a week. It doesn’t have to be tuna, but tuna certainly counts.
â€The FDA and EPA recommend that pregnant women, women who may become pregnant, nursing moms, and young children in particular eat no more than two six-ounce servings per week of tuna lower in mercury, like canned light tuna. A six-ounce serving is about the size of two decks of cards.â€
Overall, the benefits outweigh the risks if care is taken, said Marshall. “We know that fish is a wonderful lean source of protein, and even the fattier fish, like salmon, sardines and tuna, are loaded with good fats, those omega-3 fatty acids that we know are good for your heart and your brain,†she says.
â€And there is recent research to suggest that eating fish during pregnancy can have beneficial affects on the brain development on the fetus. So we have to strike a balance between getting the health benefits from fish without overdoing it on the mercury for pregnant women and young children.â€