by Josephine Quiocho

To eat or not to eat fish: the new battle in food wars!  Various debates regarding contamination levels in seafood have brought confusion over the role of fish in a healthy diet.  Do pollutants in fish negate all nutritional benefits and is there a difference in the farmed or fresh variety?  Should we toss the fish back and order up a Big Mac instead?  Read on for some insight into our vast aquaculture.

The Benefits of Fish

Numerous studies have pointed out the health benefits in consuming fish regularly.  Consumption of fish or fish oil has been shown to decrease mortality rates from coronary heart disease, reduce cognitive decline and dementia, enhance prenatal and infant neurodevelopment and intelligence, as well as aid with depression and other neuropsychiatric disorders.  Other studies have suggested that fish consumption can protect against memory loss and stroke and may help relieve rheumatoid arthritis, lower blood pressure and even protect against some cancers.  (1, 6)  Fish accomplish these life-saving feats by their healthy composition of good fat, particularly the Omega-3 fats.

Risks of Contamination

Mercury is a heavy metal emitted from both natural and human sources and ends up in our lakes and oceans where it concentrates within sea animals.  Larger, longer-living predators (eg. swordfish and shark) have higher concentrations of mercury, while shorter-lived species (eg. shellfish and salmon) have very low concentrations.  How the fish is prepared, has very little impact on mercury concentration.  PCBs and dioxins are cancer-causing industrial chemicals that have been either banned or greatly reduced in use since the 1970s.  These chemicals still persist in our lakes, streams, and oceans.  (2)

The Farmed versus Wild Debate

“Farmed” or “Ocean-raised” fish refer to fish commercially produced in large holding tanks or cages in the ocean.  It would seem that raising fish in captivity would be a logical alternative to emptying the oceans but rather, environmentalists compare the growing aquaculture industry to large cattle farms and warn of the dangers of crowded cages that expose farmed and wild fish to disease, pollute the surrounding ocean, and require the use of antibiotics.  (5)

Benefits versus Risk

The bottom line – the benefits to our health of eating fish, farmed or wild, fresh or canned – far outweigh the risks!  In 2004, the FDA and EPA reported that “fish and shellfish are an important part of a healthy diet..and can contribute to a healthy heart and to healthy, well-developed children”.  According to a study presented by the American Heart Association’s 41st Annual Conference on Cardiovascular Disease, Epidemiology and Prevention, “Older individuals are less likely to die from a heart attack if they eat at least one serving of fatty fish per week.”  (5)

However, since all fish do contain some level of contaminants, it is important to eat fish wisely, especially for children; soon-to-be pregnant, pregnant, or nursing mothers. The FDA/EPA suggest:

1. Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.
2. Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury.
3. Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don’t consume any other fish during that week.

With their composition of good fats and protein, along with selenium, iron, and zinc, fish and shellfish should remain a staple in a healthy diet!  As per our core principles here at Nutrition for You, always consider moderation, variety, and balance when making your food choices.  The choice is neither to indulge nor completely eliminate fish but, as any other food, to choose the most beneficial option.  Fish or famine?  Fish or Big Mac?  We say, go for the fish; even if it is farmed!

Resources

* Levels of methylmercury in the various types of fish: http://www.cfsan.fda.gov/~frf/sea-mehg.html or http://www.epa.gov/ost/fish.
* Monterey Bay Aquarium’s Advisory:  http://www.montereybayaquarium.org/cr/seafoodwatch.aspx

References

1. Davis, Kevin.  “A Fish Story.“  Intelihealth. 19 July 2001.  Aetna.  5 Feb. 2008
2. Ignelzi, R.J.  “Eating fish: There’s a catch.” Environmental Working Group. 19 April 2007.  9 Feb. 2008
3. Mozaffarian, Dariush, MD, DrPH, Rimm, Eric B., ScD.  Fish Intake, Contaminants, and Human Health. JAMA. 2006; 296: 1885-1899.
4. U.S. Department of Health and Human Services and U.S. Environmental Protection Agency. “What You Need to Know About Mercury in Fish and Shellfish.“  March 2004.  9 Feb. 2008
5. Waldman, Helayne.  “Wild Pacific salmon rates high for nutrition, health.“  Environmental Working Group.   3 April 2006.  11 Feb. 2008.
6. Welland, Diane, MS, RD.  Holy Mackerel!  Go Fish for an Ocean of Omega-3 Benefits.  Today’s Dietitian.  Nov. 2008, Vol. 10, No. 11: 28-33.