A consumer s dilemma hit millions of salmon lovers smack in the face after scientists reported high levels of pollutants in farm-raised salmon. That s the affordable salmon, which now ranks as America s third-favorite fish behind canned tuna and shrimp.
Should consumers still snare a slab of farmed salmon for $4 to $5 a pound at the supermarket and order the restaurant s grilled salmon special? Or is it safer to pay sticker-shock prices for grown-up-in-the-wild fish?
Should they still eat salmon at least twice a week for its heart healthy omega-3 fats, as the American Heart Association long has recommended? Or should they heed the new study s advice and limit consumption?
The study, headed by Dr. Ronald A. Hites of Indiana University and published in the journal Science, compared pollutant levels in more than 2 tons of farmed and wild salmon from different areas of the world.
Farmed salmon contained levels of 13 pollutants that averaged 11 times higher than those in wild salmon. The researchers concluded that people could safely eat the most heavily contaminated salmon only six times a year.
Termed dioxinlike compounds, the chemicals are everywhere in the environment. Fish and other animals absorb them in food and levels build up in their fat. Humans get them mainly from eating fish, meat, and dairy products. Farmed salmon get the compounds from the fish feed used to fatten them in pens.
Scientists suspect that high levels of dioxinlike compounds can increase the risk of certain cancers, harm the developing brains of fetuses and infants, and have other ill effects.
Farmed salmon is raised in coastal areas of northern Europe, North America, and Chile. Fish farming changed salmon from a pricey seasonal delicacy into a deliciously affordable year-round staple. But it stirred controversy over environmental damage from salmon farms and economic consequences in putting fishermen out of work.
In making decisions, consumers should know that the study found only a small increase in risk, according to Dr. Charles Santerre, an authority on chemical contaminants in food at Purdue University. He was not involved in the study.
“The risks were extremely low - on the order of 1 in 100,000,” Dr. Santerre said in an interview. “That means if 100,000 people ate 8 ounces of farm-raised salmon twice a week for 70 years, contaminants in the fish would cause one additional case of cancer. The cancer risk from salmon is small compared to the benefits on the heart.”
The study will have no immediate effect on the AHA s recommendations that people eat salmon and other fatty fish at least twice a week.
Dr. Alice Lichtenstein of Tufts University, a member of the AHA nutrition panel that drafts the recommendation, said the new study probably will be discussed at the panel s next meeting in April.
“Right now, cardiovascular disease is still the leading cause of death in the United States,” she said. “For most of the population, the risk of cardiovascular disease far outweighs the risk of these contaminants.”
The AHA “scientific statement” on fish consumption, updated in 2002 (http://circ.ahajournals.org/cgi/content/full/106/21/2747), says omega-3 fatty acids, such as those in salmon, seem to reduce the risk of heart attacks and sudden death from heart attacks.
About 1.1 million people suffer a heart attack each year in the United States and almost 500,000 die. Half occur within an hour of the first symptoms.
The recommendations state, however, that people should eat not just salmon but a variety of fish to minimize exposure to mercury and other contaminants. Good sources of omega-3 fats include tuna, mackerel, and other oily fish; cod liver oil; and walnuts and flaxseeds. Pills containing fish oil and other omega-3 supplements also are available, AHA said.
Dr. Lichtenstein noted that the guidelines advise consumers to be aware of both the risks and benefits of fish consumption in their stage of life.
Dr. Robert Lawrence of Johns Hopkins University noted another way in which the salmon study can help consumers fine-tune their decisions. He chaired a National Academy of Sciences panel that in 2003 considered ways to reduce dioxinlike compounds in the food supply.
“The salmon study has now provided some of the much-needed data to guide consumers on their choice of salmon, based on geographic origin and whether farmed or wild,” he said.
Consider geography. The highest dioxinlike compound levels were in salmon farmed in Northern Europe, followed by North America and Chile.
About 56 percent of the farmed salmon sold in the United States comes from Chile, 36 percent from Canada, and only 7 percent from Europe, according to Dr. Santerre. His advice to those concerned about the DLC risk: Check the country of origin when buying or ordering salmon.
The NAS study concluded that limiting fish consumption was not the right solution to dioxinlike compound contamination because of the health benefits of omega-3 fats.
Rather, it called for measures to reduce dioxinlike compound in farmed and wild fish.