Fish is no longer a health food.
Today, it is widely recommended that people obtain their EFAs from fish. For vegans and some vegetarians, this is not an option. Among the main problems with this advice is that all marine life has varying levels of toxins and pollutants. One of the nastiest is a class of contaminants called POPs (Persistent Organic Pollutants).1 This category consists mainly of dioxin, PCBs (polychlorinated biphenyls), and DDT. These cause a host of health problems, including reproductive difficulties, cancers, and neurological disorders. Those most at risk are ones with weakened immune systems (which include a good portion of the so-called healthy population), children, pregnant women, and the elderly.
Dioxins and PCBs are two of the twelve2 most dangerous chemicals known to man because, not only are they toxic, persistent, and bio-accumulative, but they can also be carried long distances in air currents, thereby posing a threat to humans and wildlife living in remote places once thought to be safe. Because they are also fat soluble, oily fish and fish oil supplements can be rich sources of POPs. These toxic chemicals, along with heavy metals, are especially concentrated in the livers of fish an important fact to consider if taking fish liver oil supplements. It is no secret now that people who regularly consume fish will have larger levels of toxic chemicals in their bodies than those who eat fish only occasionally or who do not consume it at all.
Another chemical of concern is mercury.3 Although it occurs naturally in the environment, most is released by incineration and coal-burning power plants and by mining and industrial processes. In the US alone, more than 40 tons of mercury are released into the air every year, eventually ending up in water where it changes into a form called methyl mercury, which accumulates in fish as they grow older and bigger. Fish that tend to have high levels of POPs in their bodies are also ones more susceptible to accumulations of mercury.
Women in coastal areas have higher levels of mercury than those who live inland.4 Ironically, pregnant women are told to eat more fish to obtain valuable omega-3 fatty acids for their unborn child. By doing this, however, they are exposing greater risk to their fetuses. Fetal exposure to mercury can cause learning deficits and other neurological problems. This is not an isolated problem occurring in the far north. It is estimated that a full 10% of American women (about 7 million) have mercury levels above what is considered to be average. Despite these findings, fish is still being recommended but in smaller doses.5
Significant amounts of EFAs are found only in ocean fish that have eaten plankton rich in ALA. This does not apply to farmed fish, which are fed various high protein concentrates. According to Professor Frank Hu, who conducted a 16-year study on omega-3 fatty acids and heart disease in women, farmed fish hardly contains any omega-3s at all.6 In addition, because of pollutants, some researchers advise that consuming more than one meal of farmed fish every month or two increases the risk of cancer.7, 8
As if that wasnt bad enough, farmed fish may also contain flame retardants. Although these have been found mainly in cod liver oil, farmed fish (including European salmon) that are given feed containing liver oils are more likely to have PBDEs (polybrominated diphenyl ethers). PBDEs are showing up in a wide variety of unusual places such as human breast milk in the United States and peregrine falcon eggs in Sweden. Fish oils are also used as feed supplements for farm animals, including sheep, cows, and chickens.9
Additional studies have shown a paradox concerning the elderly who are encouraged to eat fish. Research found that, while an increased consumption of fish was associated with a decreased risk of late age-related maculopathy (ARM), it did interfere with the absorption of vitamin E,10 one very necessary in reducing risk of several disorders, including visual disturbances.11, 12, 13
To be sure, contaminants are also found in plant foods. This is why it is so important to obtain organic foods14 whenever possible. While organic produce may not be available in all areas, it does present reason enough for people to make every effort to have them grown in their communities and brought into their stores. Until then, consume more foods that contain the least amount of contaminants (found at the bottom of the page).
Aside from contaminants, fish is being recognized as a major food and occupational allergen. Reactions to fish are among the most common food allergies found in adults and children.15, 16, 17, 18, 19, 20, 21 But fish is not always obvious. Fish can be found in such items as Worcestershire sauce, which may contain anchovies, Caesar salad, and imitation seafood.22
References
- 1GPA (Global Programme of Action). “How can POPs Enter and Accumulate in Fish and Other Living Marine Organisms?”
- 2OCA (Organic Consumers Association). “130 Nations Will Eliminate World’s 12 Worst Pesticides and Industrial Chemicals.”
http://www.organicconsumers.org/foodsafety/pesticides050405.cfm - 3USGS (US Geological Survey). Oct. 2000. Fact sheet. “Mercury in the Environment.” http://www.usgs.gov/themes/factsheet/146-00/
- 4Eilperin. Washington Post, Sept.23, 2005. “Women in Coastal Areas Are Found to Have Higher Mercury Levels.”
http://www.washingtonpost.com/wp-dyn/content/article/2005/09/22/AR2005092201899.html - 5FDA and EPA. 2004. “Consumer Advisory: What you need to know about mercury in fish and shellfish.”
http://www.epa.gov/waterscience/fishadvice/advice.html - 6Hu, Bronner, Willett, Stampfer, Rexrode, Albert, Hunter, and Manson. 2002. “Fish and omega-3 fatty acid intake and risk of coronary heart disease in women.” Journal of the American Medical Association 287:1815-21.
- 7Jacobs, Ferrario, and Byrne. 2002. “Investigation of polychlorinated dibenzo-p-dioxinx, dibenzo-p-furans and selected coplanar biphenyls in Scotish farmed Atlantic salmon (Salmo salar).” Chemosphere 47(2):183-91.
- 8Hites, Foran, Carpenter, Hamilton, Knuth, and Schwager. 2004. “Global assessment of organic contaminants in farmed salmon.” Science 303:226-29.
- 9Science Daily (from the American Chemical Society). 2004. “Fish Oil Supplements May Contain Flame Retardants.”
http://www.sciencedaily.com/releases/2004/03/040317073605.htm - 10Smith, Mitchel, and Leeder. 2000. “Dietary fat and fish intake and age-related maculopathy”. Archives of Ophthalmology 118:401-404.
- 12Duff. June, 2004. “Eyes and Nutrition.”
- 13Delcourt, Cristol, Tessier, Léger, Descomps, Papoz, and the POLA Study Group. 1999. “Age-related macular degeneration and antioxidant status in the POLA study”. Archives of Opthalmology 117 (10):1384-90.
- 14Duff. August, 2005. “Organic Foods.”
- 15Hebling, McCants, Musmand, Schwartz, and Lehrer. 1996. “Immune-pathogenesis of fish allergy: identification of fish-allergic adults by skin test and radioallergsorbent test.” Annals of Allergy, Asthma and Immunology 77:48-54.
- 16James, Helm, Burks, and Leherer. 1997. “Comparison of pediatric and adult IgE antibody binding to fish proteins.” Annals of Allergy, Asthma and Immunology 79:131-37.
- 17Hansen, Bindsley-Jensen, Skov, and Poulsen. 1997. “Cod-fish allergy in adults: IgE cross-reactivity among fish species.” Annals of Allergy, Asthma and Immunology 78:187-94.
- 18Madsen. 1997. “Prevalence of food allergy intolerance in Europe.” Environmental Taxicology and Pharmacology 4:163-67.
- 19FAAN – Food Allergy and Anaphylaxis Network. March, 2004. “Americans with Seafood Allergies More Than Double Those with Peanut Allergies.”
- 20Tidwell. About dot com. Seafood Allergies.
- 21Auckland Allergy Clinic. Feb, 2003. Seafood Allergy.
- http://www.allergyclinic.co.nz/guides/51.html
- 22Cleveland Clinic Health Information. “Special Diets for Food Allergies.”
http://www.clevelandclinic.org/health/health-info/docs/2900/2987.asp?index=10014
Other References
- Find Articles.“Shattering a myth: fish and disease” a question and answer article
http://www.findarticles.com/p/articles/mi_m0876/is_n58/ai_10843585#continue - Vegetarian and Vegan Foundation.“Fishing for Facts”
(While this article has good information, you do have to buy their references.)
- Chicago Tribune Dec.13, 2005 article on mercury in canned tuna
- CBC Canada Nov. 5, 2004 article on mercury in canned tuna
- San Francisco Chronicle June 19, 2003 article on mercury in canned tuna
