DNC NEWS: Fish are Risky Business
Subject: Striking a balance between the benefit of eating fish versus the health risk is a tricky business.
As the evidence in favor of eating fish grows, nagging questions continue to surface about health risks, especially from toxic chemicals increasingly present in fish. I've been encouraging people to eat more fish for years. Eating fish lowers the chance of having a heart attack. Fish contain Omega-3 fatty acids which are in short supply in the American Diet and which are protective against cardiovascular disease. Increasing Omega-3 fatty acids in the diet is useful in treating a range of other conditions as well: asthma, rheumatoid arthritis, and auto-immune diseases to name a few. A serving of fish once a week lowers fatal heart attacks by half. This crumb of information has encouraged me and many other people to eat fish regularly. A lot of fish. Maybe too much. I confess to buying weekly slabs of salmon at Costco for years and now regretting it. Eating fish lowers the risk of cardiovascular disease but what else does it do?
I sent out an article last fall from Science News that describes how wild Salmon spawning and dying in Alaskan lakes leave a burden of toxic chemical that adversely affect local wild life. [See Wild Salmon dump pollutants in Alaska lakes: Science News September 2003 story:http://www.nature.com/nsu/030915/030915-7.html] Now last week's Science News has a story about the level of pollutants in farm raised salmon. If wild salmon poisoned Alaskan grizzly bears what are farm raised Atlantic salmon with ten times the level of pollutants doing to me? I'll paste the current story below or here is the link directly to it.
Our oceans are badly polluted and it seems that what few fish remain concentrate those pollutants and give them back to us. With farm raised salmon the story gets even worse. It seems these fish are fed a diet of harvested fish and animal waste products. It's not just cattle who we have turned into cannibals but fish as well.
The Monterey Aquarium in California has a very informative website section called the Seafood Watch List:
It attempts to sort out which fish are best to eat both from a safety perspective and also in regards to protecting endangered species and fisheries.
If you have been trying to do the right thing and eat more fish or if you have gotten carried away and attempted an Atkin's type diet eating fish, you may now be wondering if you have done yourself harm. The most talked about toxic heavy metal from fish is mercury. There are several ways to test for mercury poisoning. The simplest is a blood serum mercury level. Recent acute exposure to high levels of mercury will show up on this test. Longer term chronic exposures are not detected as easily. A more sensitive test is a provoked urinary screen. In this test an oral dose of a chemical chelating agent is given and the urine then analyzed for all toxic metals which are pulled out of the body as a result.
We have been using DMSA as the provoking agent followed by a six hour urine collection and analysis by Doctor's Data.
It is possible to test for PCBs, dioxin and other chemicals that you may have accumulated from eating large amounts of fish but I have less experience doing so. The lab we use is Accu-Chem
( www.accuchemlabs.com ).
The difficulty is that you have to fairly specific in regard to what to test for.
So where does this leave us? Omega-3 fatty acids are essential for good health. The best dietary source, ocean fish may be risky to eat. What sources are left. Distilled fish oils are the most concentrated sources of moega-3 fatty acids and the processing they undergo along with the stringent testing renders them safe. We are continually updating our commercial sources as better products come on the market.
Nuts as always continue to be a good source of essential fatty acids. Besides being relatively safe from contamination they have an advantage over fish; they are shelf stable. You can leave a jar of nuts on your counter for months on end. You can't do that with a piece of fish.
Farmed salmon harbour pollutants
Study may undermine salmon's status as a 'healthy' food.
9 January 2004
Salmon is high in healthy omega-3 fatty acids, but also in unhealthy PCB's.
Farmed salmon carry up to ten times as much cancer-causing chemicals as their wild counterparts, according to a worldwide survey of fish destined for supermarket shelves1.
The contaminants - a group of compounds called organochlorides - include a family of industrial pollutants called polychlorinated biphenyls (PCBs). In humans, these chemicals are linked to cancer and to developmental defects such as stunted intelligence.
The findings deal a blow to salmon's perceived status as a healthy food, says David Carpenter of the University at Albany in Rensselaer , New York , a member of the study team. Salmon is rich in omega-3 fatty acids, which protect against heart disease. But, says Carpenter, the presence of PCBs means that people who have a low risk of heart problems might be advised to steer clear.
The study estimates that, based on the US Environmental Protection Agency's recommended maximum intake of organochlorides, Scottish consumers would be advised to limit their salmon consumption to just six meals a year.
John Webster, scientific adviser to Scottish Quality Salmon, which represents Scotland 's salmon-farming industry, says that such extrapolations are "scaremongering". "If we were to take that sort of advice we'd have nothing on the menu at all," he says. Webster says that a similar analysis by his group showed lower levels of contamination than Carpenter's team reports.
Robert Lawrence, a public-health expert at Johns Hopkins University in Baltimore , agrees that the risks of eating farmed salmon may outweigh the benefits for some people. "It might be good for middle-aged men but not for childbearing women and children," he says.
Carpenter and his colleagues purchased salmon from 16 cities in Europe and North America . PCB levels in fish from the world's salmon-farming hotspots - Europe , North America and Chile - were up to ten times those in wild-caught salmon. Farms in Scotland and the nearby Faroe Islands were the worst affected.
This is understandable given that Northern Europe has a long tradition of industry, says Carpenter. PCBs are pumped out by the manufacture of materials such as paints and flame-retardants, and by waste incineration.
Carpenter suspects that the pollutants find their way into the small fish that are caught and processed into salmon feed. He suggests that farmers consider making their salmon vegetarian, substituting soybeans or flaxseed for fish protein, in order to reduce the problem.
Lawrence agrees that fish farms could benefit from a shake-up. He points out that salmon in US farms are also fed recycled fat from slaughtered agricultural animals such as cows. By feeding the salmon material from the top of the food chain - which may already have high PCB levels - the problem can be exacerbated.
Carpenter says that those striving for a healthy heart have other options. Flaxseed oil, for example, is rich in omega-3 acids. "We're not telling people not to eat fish," he says, "but there are alternative sources."
Hites, R. A. et al. Global assessment of organic contaminants in farmed salmon. Science, 303, 226 - 229, (2004).
© Nature News Service / Macmillan Magazines Ltd 2004