Thursday, October 19, 2006

Tuna Is the Biggest Source of Mercury from Fish: Is It Safe to Eat Fish?

A new article in the Journal of the American Medical Association advises Americans to continue eating fish in spite of the fact that at least 44 of our 50 states now post mercury advisories. The author's rationale is that people who eat fish have 35% fewer heart attacks.

Fewer heart attacks than whom? Fewer than the average American who eats 176 pounds of meat per year? Or fewer than vegetarians? Or vegans? So misleading....

Any deviation from the Standard American Diet, which is very high in animal fat, is likely to improve the risk of heart attacks.

But, that said, what is the scoop on mercury? Is it safe or not? That depends on whom you ask, and what the alternative is. Mercury has been demonstrated in several studies to cause neurological deficits in fetuses and young children. Even the above-mentioned article in the Journal of the AMA acknowledges that. But the amount of mercury consumed seems to be a crucial factor.

According to the Natural Resources Defense Council, the most common source of mercury exposure for Americans is tuna fish. Tuna does not contain the highest concentration of mercury of any fish, but since Americans eat much more tuna than they do other mercury-laden fish, such as swordfish or shark, it poses a greater health threat. For more from the NRDC, see their guides to mercury levels in fish and to eating tuna safely.

The NRDC also reports that subsistence and sports fishermen who eat their catch can be at a particularly high risk of mercury poisoning if they fish regularly in contaminated waters. Across the United States, mercury pollution is known to have contaminated 12 million acres of lakes, estuaries, and wetlands (30 percent of the total), and 473,000 miles of streams, rivers, and coasts. And many waterways have not even been tested. In 2003, 44 states issued fish consumption advisories, warning citizens to limit how often they eat certain types of fish caught in the state's waters because they are contaminated with mercury.

Environmental Defense and Oceans Alive have published guides to choosing fish for those who wish to minimize health risks and minimize the environmental impacts on marine ecosystems. The ED site evaluates contaminants, such as mercury, individually.

Is it necessary to eat fish? No. The omega-3 fatty acids seem to be the fish ingredient that motivates people to choose fish. But you can get plenty of omega-3 fatty acids from vegetable sources that have zero mercury. The most generous recommendations for fish still say to eat no more than 12 ounces per week, which is two average servings. One easy and safe way to get an abundance of omega-3 fatty acids every day is to grind up two level tablespoons of organic golden flax seeds (available at any natural foods store) and mix them with dry oatmeal before adding hot water. The seeds should be ground just before eating, or they loose some nutrients. I use a coffee grinder. Add a small handful of walnuts on top of the oatmeal for even more omega-3s. Scrumptious.

Flaxseed Provides Comparable Cholesterol-Lowering Benefits to Statin Drugs

In a study involving 40 patients with high cholesterol (greater than 240 mg/dL), daily consumption of 20 grams of ground flaxseed was compared to taking a statin drug. After 60 days, significant reductions were seen in total cholesterol, LDL cholesterol, triglycerides and the ratio of total to HDL cholesterol-in both groups. Those receiving flaxseed did just as well as those given statin drugs. For more info, see this well-documented article about the health benefits of flax.

Environmental Concerns
I won't be eating any fish, but for reasons of sustainability as well as mercury exposure. The "long-lines," gill nets, and blastfishing techniques used by today's modern fishing fleets are destroying our marine ecosystems the world over.

How does mercury get in our waters to being with? From coal-fired power plants, which provide 57% of the electricity in our country. For a thorough indictment of coal as an energy source, and an exciting review of solutions to coal, see Jeff Barrie's important documentary, Kilowatt Ours.


Anonymous said...

Thanks for all the good information. Fish had snuck back into my diet over the last few years after a long time away from it, but I think in light of what you have here, I'm better off without it.
I already use flaxseed, and find it a good addition to my diet. I got a grinder that is pretty easy to use; it's the size of a large salt shaker. I use it to put ground flaxseeds on lots of things. I don't know what the effects on my cholesterol have been so far, but I figure it's got to be better than doing nothing.

PixieSwimmer said...

Good information!!

How about addressing tuna fish as a source of protein, B12 & 'natural antidepressant'? (some people eat it for that too - personally, my cholesterol levels are probably much too low as it is!!) - or giving links to info/alternatives on that-?

Anonymous said...

thanks for the commen sense approach to mercury - the government wants to protect the fishing industry by playing the portion numbers game - when I read on the tuna can that there is mercury contamination
I gave up one of my favorite foods realizing that this was the beginning of environmental toxicity beginning to seriously affect our food.If it was arsenic would it make sense to just eat smaller portions?
peace Mike

emapeal said...

thanks fo the cmmern sense approach to ercury - let's face it the government must protect the fishing industry pece M

Sally Kneidel, PhD said...

Thanks Mike for your comment. That's amazing - I didn't know that tuna cans have mercury warnings! (or some do) Wow. I'm glad they do, but it just surprises me that they're still able to sell the cans with mercury warnings. That's pretty freaky - they people are choosing to eat food they know has mercury in it. Or maybe they're not reading the label....