New Yorkers' Higher Blood Mercury Could Be Sign Of Healthy Fish Eating

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Main Category: Nutrition / Diet
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Article Date: 24 Jul 2007 - 2:00 PDT

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According to a survey released by the New York health department yesterday, 1 in 4 of the city's dwellers has elevated blood mercury. But this is not necessarily a bad thing, since the levels are mostly below the safe threshold, and could be a sign that New Yorkers are getting their much needed omega 3 fatty acids from fish. There are however, one or two groups that need to keep an eye on the type of fish they eat; Chinese women born outside the US in particular.

The elevated blood mercury levels were higher among the better off as opposed to those on lower incomes, and also among Asians, because they eat more fish, said the report.

Assistant commissioner for environmental surveillance and policy at the city's Department of Health and Mental Hygiene said the result is not bad news, although the levels were elevated for one quarter of the population, they do not pose a risk for most adults.

There may however be a slight cause for concern if these levels are reflected in children, especially those under 6, and also women who are pregnant and breast feeding, because mercury affects the development of the brain and central nervous system in the very young, and fetuses in particular.

Kass told the press that:

"It's not bad for the average adult who isn't reproducing; for a brief period of life, during pregnancy, while breast-feeding, it would be best to keep mercury levels down," he said.

The US Centers for Disease Control and Prevention (CDC) conducts nationwide monitoring of mercury in people and recent surveillance shows that most Americans have blood mercury levels (blood Hg) below a level (5.8 micrograms per litre of whole blood) linked to adverse health effects.

The mercury information came from a New York city's version of the CDC's Health and Nutrition Examination Survey, covered over 1,800 adults and was completed in 2004. Its findings showed that for New York residents:

• The average level of blood Hg among New Yorkers was 2.8 micrograms per litre.
• People on higher incomes had an average blood Hg of 3.6 micrograms per litre.
• People on lower incomes had an average of 2.4.
• Women between 20 and 49 years of age had an average blood Hg of 2.64 micrograms per litre (the US national average for a similar group is 0.83).
• Asian women on average had a blood Hg level of 4.1 micorgrammes per litre.
• 66 per cent of Chinese women born outside the US had blood Hg levels at 5 micrograms per litre or higher.

The New York Department for Health and Mental Hygiene said that the purpose of issuing this news was not to stop New Yorkers eating fish, which on balance is good for health, but to warm pregnant women to be more careful about the fish they eat, and to reach out to Asian women, particularly Chinese women.

They have issued a brochure in several languages (available through the city's 311 telephone information line) telling pregnant and breast feeding women which fish to avoid and which fish are ok. For instance, they should avoid fish that have higher levels of mercury, such as fresh tuna, swordfish, and Chilean sea bass. But they could eat adult portions (6 ounces) of tilapia, herring and whiting up to five times a week.

Health officials also do not recommend that people eat fish caught in New York Harbour, or from the East or Hudson rivers, because they could be contaminated with other poisons.

The non-profit organization Center for Consumer Freedom (CCF) said that the report on the blood mercury levels of New Yorkers is an indication of their good health. They said that since the year 2000, nutritionists have been saying that Americans need to quadruple their fish intake in order to get enough omega 3 fatty acids.

The CCF said it looks like New Yorkers are getting closer to that goal than residents in other states. The good news, they said, is that the levels of mercury that come along with getting the right levels of omega 3 from eating fish are too low to be a health concern.

CCF Director of Research, David Martosko said:

"This fish scare is likely to cause a tremendous amount of harm. Scaring New Yorkers away from sushi bars is public health malpractice. Fish is a health food. Period."

The CCF said that the reference level of 5.8 microgrammes per litre of blood was set by the Environmental Protection Agency (EPA) and has a "built in safety cushion of 1,000 per cent".

They said the medical literature does not contain a single case of mercury poisoning from eating fish among Americans. They have issued their own report, called Seafood Science Since Madison, outlining the science that has emerged in the last year on this subject.

The CCF wished to remind consumers that:

"Scientific evidence continues to serve as a reminder that the health benefits of eating fish far outweigh the hypothetical risks for every segment of the population; including pregnant women."

Click here to download the New York City health department brochure "Eat Fish, Choose Wisely" (PDF reader required).

Click here for Mercury Facts (consumer group site) and see the CCF's "Seafood Science Since Madison" report.

Written by: Catharine Paddock
Writer: Medical News Today
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today