Fishing For Omega-3 Fatty Acids

By Steven Taormina

Recent reports on toxic chemicals found in store-bought fish have cast doubts over fish’s health benefits versus risks. Deep-sea, cold-water fish such as tuna and salmon are excellent sources of omega-3 fatty acids, but levels of mercury and PCBs (polychlorinated biphenyls) found in some types of fish are potentially dangerous, especially to pregnant women and children.

According to the Centers for Disease Control and Prevention, 8 percent of U.S. women of childbearing age have levels of mercury in their blood that present developmental risks for their babies. Mercury is toxic to a fetus’s developing brain and nervous system, and it can have permanent, negative effects on a child’s intelligence, speech, and motor development.

PCBs have been linked to impaired fetal brain development, cancer, and other serious diseases. These chemicals were banned in the United States in the late 1970s, but they still persist in the environment today and appear to be tainting global aquaculture (or fish farming) feed supplies.

Fish farming accounts for six of every 10 salmon fillets sold in stores and restaurants today. In a 2003 international study of store-bought salmon, researchers found that levels of 14 toxins, including PCBs and dioxin, were significantly higher in European and North American farm-raised salmon than in wild Pacific salmon. Researchers concluded that farm-raised salmon may pose health risks to people when consumed more than once or twice per month.

Another recent study, this one conducted by the nonprofit Environ-mental Working Group (EWG), found seven of 10 farm-raised salmon bought from U.S. grocery stores were contaminated with enough PCBs that they raised cancer-risk concerns relative to health standards set by the U.S. Environmental Protection Agency.

In February 2004, EWG and the Center for Environmental Health (CEH) filed notice in California that they intend to sue 50 salmon farms, fish processors, and grocery chains under Proposition 65, the state’s antitoxics law. “Our goal is to challenge them to change their practices so their fish is safe to eat,” said Michael Green, executive director for CEH.

Buying Safe, Healthy Fish
Of course, not all fish are tainted with unsafe levels of toxins. Shoppers have many choices and should not be afraid to ask local grocers about the sources of fish being sold.

“When considering human health and farmed fish, concerned consumers should know exactly what the fish are being fed and the quality of water they are swimming in,” says Henry Lovejoy, president and founder of EcoFish, a company in Portsmouth, NH, that uses strict selection criteria for the fish it sells.

Wild Alaskan salmon is a safe choice, says Lovejoy. “It’s high in heart-healthy omega 3s and is not known to have mercury or PCB contamination. From a chemical-free, nonpolluting farm, trout and tilapia are good choices,” he says.

Larger, carnivorous fish such as shark and swordfish are most likely to contain potentially dangerous levels of mercury, according to the U.S. Food and Drug Administration. In March 2004, the agency issued the following revised warning to women who are pregnant, nursing, or considering pregnancy: “Do not eat Shark, Swordfish, King Mackerel or Tilefish because they contain high levels of mercury. Levels of mercury in other fish can vary. Eat up to 12 ounces (two average meals) a week of a variety of fish and shellfish that are lower in mercury.” Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.

Only in the latest warning did the FDA include canned albacore tuna, stating that albacore (“white”) tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, they suggest eating up to six ounces (one average meal) of albacore tuna per week. Lovejoy says tuna is a “borderline” fish that may be contaminated with mercury, depending on the size of the fish when caught. “Generally the FDA says consumers should be careful with tuna since some species can have high levels of mercury.

Consumers who buy wild salmon and “ecologically” raised fish may understand that safety is one benefit of their choice. Another is the health-enriching omega-3 fatty acids found in many fish.

Benefits of Omega-3 Fatty Acids
Omega 3 is the name for a group of polyunsaturated fats that are called “essential fatty acids” because, unlike some nutrients, the human body cannot produce them. Omega-3 fats must be obtained from foods, and the most common dietary sources are deep-sea, cold-water fish including tuna, salmon, mackerel, sardines, herring, and anchovies.

“The health-promoting effects of the omega-3 fats are most strongly seen with regard to coronary heart disease (CHD),” says Richard M. Delany, MD, FACC, an integrative physician in Milton, Mass., who uses a special blood test to assess body stores of omega-3 fats. “The key components of fish that are felt to be ‘cardioprotective’ are the combined presence of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid),” he says.

Studies published as early as 1985 provide evidence for the benefits of EPA and DHA. People in one study with a high risk for CHD who regularly consumed fish reduced their risk of dying by 50 percent. In another study, more than 20,000 men were followed for 11 years. When compared with matched controls, men who consumed fish at least once per week had a 48 percent risk reduction of sudden death compared to men who consumed fish less than once monthly.

But omega 3s are not a heart-disease panacea. “Any proactive health recommendation has more relevance for the individual who is at a higher risk of a specific disease” than a person who is at a lower risk, says Delany. For example, for those whose risk of CHD is low, the benefits of fish consumption are not as well demonstrated.

In addition to cardiovascular health, evidence exists for omega 3s’ benefits for the mind and joints. The National Center for Complementary and Alternative Medicine is currently studying omega 3s’ effects on bipolar disorder and depression, and a review of multiple studies shows omega 3s are beneficial in the treatment of a wide range of inflammatory conditions, including arthritis.

To attain these heart-healthy and possibly other benefits, the FDA suggests that adults consume between 600 mg and 2 grams per day of omega-3 fatty acids. An eight-ounce serving of cooked wild Coho salmon provides approximately 1 gram of combined EPA and DHA.

If buying wild-caught fish is difficult, then fish-oil supplements made from cold-water fish that have been detoxified and tested for heavy metals is a safe, healthy option. In fact, until the fish-farming industry is able to allay consumer fears about contaminated fish, consumers seeking the health benefits of omega-3 fatty acids may find fish-oil supplements to be their best choice.

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