CBS) 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.

29 Jul


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.”

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.”

For most of us, the level of mercury absorbed by normal consumption of tuna sandwiches or the occasional sushi dinner will cause no harm.

“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.

“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.”

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.

“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.”

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.

“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.”

2 Responses to “CBS) 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.”

  1. BH Sales July 29, 2007 at 10:32 pm #

    As a supplying vendor and consumer of fish oil-


  2. PETER H. FLOURNOY July 30, 2007 at 12:01 am #

    Dear Sirs:

    What seems to always get lost in these articles is that there are two very different kinds of albacore which is canned and sold fresh in this and other countries. About 80% of the albacore canned by the major processors comes from the longline fishery which targets the older, larger albacore. Longline as a gear type has in the past interacted unfavorably with sea turtles. This is why the same people who are against the administration’s perceived weakening of clean air standards have joined with the people interested in saving sea turtles to attack all tuna, and now in particular albacore.

    The other 20% of albacore processed by the major caners and also by “boutique” or family canners (a lot of which is sold at Whole Foods, Farmers Markets, Trader Joe’s etc)is smaller younger albacore which is caught on the surface of the ocean which troll gear. This albacore being younger and smaller than the other albacore consistently tests lower in mercury content since it does not suffer from the cumulative nature of mercury. Further, the troll gear does not interact with sea turtles, marine mammals, or seabirds. Environmental groups such as NRDC have once again used a broad brush in their campaigns, as have other groups. The same thing happened a few years ago when there were sustainability problems with Atlantic swordfish. Ignoring the fact that the U.S. fleet was tightly regulated and fishing BELOW its quota, the groups started a “Give Swordfish a Break Campaign” making no distinction between U.S. caught swordfish and foreign caught, nor any distinction between Atlantic swordfish and Pacific swordfish.

    These national environmental campaigns can not be bothered by such distinctions even though the groups involved know the true story. EPA-FDA’s fish advisory is so confusing already on fish that that those agencies, which also have the documented scientific information do not change or refine their message.

    I represent an organization which represents about 50% of all west coast albacore trollers (about 95% of those who belong to a fishing association). These are primarily family run small business operations. They are being badly hurt.

    Please look at the web-site There is other information available from some of the aquariums (such as the Monterrey Aquarium) or educational organizations (I believe the University of Florida) which put out wallet sized charts on the best fish to eat.
    Finally, there is the as yet unpublicized information on how selenium in fish interacts to neutralize the normal mercury content to render it harmless to the human body.

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