Fish Intake, Contaminants, and Human Health

An American researcher has collected data from both USA and Europe about the potential risks and benefits from eating different fish. The results have been gathered by The Journal of the American Medical Association (JAMA), which promotes the science and art of medicine and the betterment of the Public Health.

The result and consclusion is not that unexpected, but salmon in the wild do not have a greater amount of quicksilver in them than the salmon that has grown up with the aid of man according to the study, if we are to believe what DN writes. Some fish do have a greater amount of Omega-3 in them but the radical difference can be find between various sorts of fish.

DN have chosen to contribute with graphics on which fish that has the greater amount of 'good' fat and which fish that has the most amount of 'bad' fat. This piece of graphic is problematic for some reasons such as the absence of information on other contents that might be good with the fish that contain less good fat.

However, EPA and DHA are the types of Omega-3 that has heart-protecting effects according to the study. Moreover, we also have to keep in mind that it was American researchers who, only two years ago, warned us that the Norweigan salmon contained high amounts of toxins such as PCB and dioxins compared to salmon from the west coast in the United States. The reaserchers gained a lot of attention but also drew a lot of criticism. European toxicologists opposed the American researchers with their own research data.

Here is the abstract from the report:

Fish Intake, Contaminants, and Human Health
Evaluating the Risks and the Benefits

Dariush Mozaffarian, MD, DrPH; Eric B. Rimm, ScD
JAMA. 2006;296:1885-1899.

Context Fish (finfish or shellfish) may have health benefits and also contain contaminants, resulting in confusion over the role of fish consumption in a healthy diet.

Evidence Acquisition We searched MEDLINE, governmental reports, and meta-analyses, supplemented by hand reviews of references and direct investigator contacts, to identify reports published through April 2006 evaluating (1) intake of fish or fish oil and cardiovascular risk, (2) effects of methylmercury and fish oil on early neurodevelopment, (3) risks of methylmercury for cardiovascular and neurologic outcomes in adults, and (4) health risks of dioxins and polychlorinated biphenyls in fish. We concentrated on studies evaluating risk in humans, focusing on evidence, when available, from randomized trials and large prospective studies. When possible, meta-analyses were performed to characterize benefits and risks most precisely.

Evidence Synthesis Modest consumption of fish (eg, 1-2 servings/wk), especially species higher in the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), reduces risk of coronary death by 36% (95% confidence interval, 20%-50%; P<.001) and total mortality by 17% (95% confidence interval, 0%-32%; P = .046) and may favorably affect other clinical outcomes. Intake of 250 mg/d of EPA and DHA appears sufficient for primary prevention. DHA appears beneficial for, and low-level methylmercury may adversely affect, early neurodevelopment. Women of childbearing age and nursing mothers should consume 2 seafood servings/wk, limiting intake of selected species. Health effects of low-level methylmercury in adults are not clearly established; methylmercury may modestly decrease the cardiovascular benefits of fish intake. A variety of seafood should be consumed; individuals with very high consumption (5 servings/wk) should limit intake of species highest in mercury levels. Levels of dioxins and polychlorinated biphenyls in fish are low, and potential carcinogenic and other effects are outweighed by potential benefits of fish intake and should have little impact on choices or consumption of seafood (women of childbearing age should consult regional advisories for locally caught freshwater fish).

Conclusions For major health outcomes among adults, based on both the strength of the evidence and the potential magnitudes of effect, the benefits of fish intake exceed the potential risks. For women of childbearing age, benefits of modest fish intake, excepting a few selected species, also outweigh risks.

Author Affiliations: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School; and Departments of Epidemiology and Nutrition, Harvard School of Public Health, Boston, Mass.


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