Copley News Services, R.J. Ignelzi
Published April 19, 2007
The confusion over which fish are safe to eat has consumers floundering.
Do pollutants contaminate all nutritional benefits?
Does farmed salmon offer the same health wonders as wild?
Should everyone can the canned tuna?
It's enough to make you toss the trout and order up a Big Mac with cheese.
And that would be a shame. Although nutritionists say there's no perfect food, lots of fish come darn close.
"Many fish are high in omega-3 fatty acids, which decrease heart attacks, decrease cholesterol and help prevent strokes. It's high in protein, zinc and iron, and it's low in fat," says Joan Rupp, a registered dietitian and instructor at San Diego State University's Department of Exercise and Nutrition Science. "If you're eating fish for dinner, it means you're not eating a bacon-and-cheese burger."
But fish's health benefits come with a catch.
Some fish have been found to contain high levels of mercury, polychlorinated bipenyls (PCBs), and other contaminants that could negate many of their virtues. Most of the time, these drawbacks aren't enough to present a risk to healthy adults who eat fish occasionally. However, some people with particular health conditions and of a certain age need to avoid some fish and restrict their consumption of others.
In 2004, the Food and Drug Administration and the Environmental Protection Agency advised pregnant and nursing women, women of child-bearing age and young children to avoid four fish because of the high mercury content. The fish are swordfish, king mackerel, tilefish and shark.
All of these fish are large predatory fish that concentrate mercury in their bodies throughout their lives through eating smaller fish that also contain mercury.
Mercury originates from natural sources and air pollution. It's toxic to the brain, heart and nervous system and especially damaging to the neurological development of infants and young children.
PCBs, cancer-causing industrial chemicals that were banned in 1976, are still found in lakes, streams and oceans.
Because of growing public concern and confusion, the Institute of Medicine reviewed the scientific evidence and recommendations from government and private health groups and issued a report, "Seafood Choices: Balancing Benefits and Risks," last October. At the same time, Harvard researchers published an analysis of studies on fish and health in the Journal of the American Medical Association.
Both concluded that the 2004 FDA/EPA fish consumption guidelines are sound. They also agree that the benefits of eating fish outweigh the risks.
Besides reducing the risk of cardiovascular disease, fish rich in omega-3 fatty acids may reverse depression, slow the mental decline that can come with age and reduce the risk of rheumatoid arthritis and some cancers, studies show. There is evidence that infants born to mothers who received omega-3 fatty acids during pregnancy have better vision and brain development.
Fish particularly plentiful in omega-3s are the oily varieties, including salmon, herring, sardines and trout.
The FDA and the EPA say that everyone, including pregnant women, should eat a variety of fish and shellfish that are low in mercury at least twice a week, unless the fish is deep-fried (a serving size is 3 ounces of cooked fish or 4 ounces of uncooked fish). Pregnant women should limit their fish or seafood consumption to 12 ounces a week. The American Heart Association recently added that healthy adults can eat 14 ounces of most fish a week without any danger.
The problem is figuring out which fish pack the biggest health bang and smallest risk for the buck.
"We don't want people to give up on fish. We just want people to make wise choices about the fish they eat," says Cathy Levenson, associate professor of nutrition at Florida State University, who co-authored a research paper ranking fish on the basis of both omega-3 fatty acid content and mercury level. "Not all fish can be put in the same category."
She believes that the "best fish by far and away is wild salmon."
The problem with farmed salmon is that it is usually high in PCBs. She explained that farmed fish is fed fish product and "any contaminants in the fish (feed) gets concentrated," she says.
But not all nutrition experts view the issue of farmed versus wild salmon as critical.
"Wild salmon has more omega-3 fatty acids than farm-raised salmon, but not enough of a difference that it should drive your salmon choice," says Cheryl Rock, researcher and professor of nutrition at the University of California San Diego's School of Medicine, noting that farm-raised usually has less mercury than the wild variety. "Farm-raised salmon is still a good source of omega-3 fatty acids, and it's a lot less expensive than wild salmon."
Tuna, the nation's most popular seafood, has also been scrutinized for its health risks. In government food safety tests, canned albacore or white tuna, in addition to fresh or frozen tuna steaks, was found to have significantly more mercury than the canned chunk light tuna. The FDA recommends that vulnerable groups (women of childbearing age and young children) eat no more than 6 ounces or one can of albacore or white tuna a week.
And if you think you can get around the fish safety controversy by skipping the real thing and just throwing back a couple of fish oil supplements, think again. Although one or two fish oil pills a day are OK, health experts don't recommend taking large quantities.
"The problem with supplements is that you can get adverse effects," Rock says. "Real high doses could interfere with (blood) clotting, especially if you're already taking anticlotting drugs. And studies suggest that with huge amounts of fish oil, there could be adverse effects for people who are prediabetic."
Nutrition experts warn people not to go off the deep end about fish with possible health risks.
"There are still plenty of great, healthy fish out there to choose from, like mahi mahi, tilapia, scallops, shrimp and cod," Rupp says. "There are so many fish that are really very safe, that there's no excuse (not to eat it)."
Instead of focusing on the dangers of eating fish, Rock encourages consumers "to pay attention to the consistency of public health advice to eat more fish and try to overcome this fear of it," she says. "Fish is a very good source of protein. In a country where we're trying to encourage people to eat less fat and red meat, fish is a perfectly acceptable replacement."
SIDEBAR
Contaminant concern
Copley News Service
Health and nutrition experts agree: The benefits of eating fish outweigh the risks. However, it's still a good idea to be aware of safety tips for the purchase and preparation of fish and seafood.
The Food and Drug Administration, with the backing of the latest report by the Institute of Medicine, offers the following recommendations for women who are or could become pregnant or who are breast-feeding: Eat up to 12 ounces of most fish a week; eat fish or seafood high in omega-3 fatty acids; eat up to 6 ounces of white (albacore) tuna a week; and avoid large predatory fish such as shark, swordfish, tilefish and king mackerel.
These recommendations are the same for children up to age 12 years.
The FDA says healthy adolescents and adult men and women who will not become pregnant can cut their risk of heart disease by eating fish with low mercury levels twice a week.
Choose fish rich in omega-3 fatty acids and low in contaminants. The best sources are salmon (wild is best), mackerel (but not king mackerel, which is high in mercury), mussels, oysters, anchovies, rainbow trout, herring and sardines.
Go for variety. Limit your exposure to contaminants by eating a wide variety of fish, especially if you're eating more than two servings of fish a week.
Choose the canned chunk light tuna instead of the white albacore variety. Albacore has more of the omega-3 fatty acids than light tuna, but it also contains three times the mercury. Although healthy adults, other than the women listed, have no restriction on their tuna consumption, many nutritionists say if you eat a lot of canned tuna, stick to the chunk light.
Buy wild salmon when it is in season and affordable. Although it is often double the price of farm-raised salmon, it has significantly less PCBs.
Cut the fat. PCBs accumulate in the fatty tissue of fish. Reduce your exposure by removing the belly and back fat before or after cooking. It's also a good idea to remove the skin before cooking because that's where a large portion of the toxins are.
Broiling, baking or grilling salmon or any other fish will cook off some of the PCBs in the fat.
Try canned salmon, most of which is Alaskan wild salmon and has less PCBs than farm-raised salmon.
Check health advisories for locally caught fish.
ONLINE HELP
Be informed. To help you make healthier fish choices, pay attention to online consumer and advocacy information and mercury calculators such as:
U.S. Food and Drug Administration,
www.cfsan.fda.gov/
U.S. Environmental Protection Agency,
www.epa.gov/mercury/fish.htm
Oceans Alive, part of the Environmental Defense,
www.oceansalive.org
Environmental Working Group,
www.ewg.org/issues/mercury
Natural Resources Defense Council,
www.nrdc.org
Seafood Choices Alliance,
www.seafoodchoices.com
Got Mercury,
www.gotmercury.org
Monterey Bay Aquarium's fish and seafood guides:
www.mbayaq.org/cr/seafoodwatch.asp
Harmonia Health,
www.harmoniahealth.com/fish.htm
SIDEBAR
Which fish to eat and how often
Here's what recommended by the Environmental Nutrition newsletter. (A serving is 3 ounces.)
- Very high levels of mercury. Avoid these fish.
king mackerel
shark
swordfish
tilefish
- High levels of mercury (0 to 1 serving a week)
bluefish
lobster
marlin
orange roughy
red snapper
bass (saltwater)
trout (freshwater)
tuna (fresh)
tuna, canned, white albacore
Medium levels of mercury (1 to 2 servings a week)
grouper
halibut
pollock
sablefish
sea trout
- Low levels of mercury (2 to 3 servings a week)
cod
crab, dungeness and blue
haddock
herring
mahi mahi
ocean perch
tuna, canned light
whitefish
- Very low levels of mercury (3 to 4 servings a week)
catfish
clams
crab, king
flounder
oysters
salmon, farmed
salmon, canned or wild Alaskan
sardines
scallops
shrimp
sole
tilapia
