Dan's Data letters #159
(page 2)Publication date: 24 January 2006.
Last modified 10-May-2013.
Apparently, "there's considerable evidence that the amount of mercury in fish has remained the same (or even decreased) during the past 100 years."
I know you're not running Dan's Food Safety Advisory Service here, but I also know you, uh, like elements and stuff, and mercury's an element, and so...
Actually, I got nothin'.
But is this true?
[Update: In the several years since this page first went up, the above activist site has turned into a parked domain - but the same arguments can be found in various other places.]
Oh, I'll give it a shot - given that I (a) eat fish, (b) don't want my brain to fall apart, (c) see an opportunity to lecture you all about the reliability of various sources of information and (d) recently had to clean up a mercury spill in the kitchen.
(That last part's a story for another day.)
The mercury-in-fish issue is not just some wacko fear campaign conducted by those unschooled about toxicity and dose response (not to mention all of the rest of the stuff that makes real science so darned difficult).
We're talking about organic mercury compounds, here, which may collectively be referred to as death on a stick. They're toxic at much lower concentrations than is the plain metallic mercury that some people have for decades been insisting is poisoning everyone with amalgam fillings. It is indisputable that, in some situations, fish have taken up enough organic mercury to very clearly be very toxic to people who eat fish a lot, and there have been various less dramatic cases, too.
The question, though, is whether ordinary fish, as bought by ordinary people who do not live in a fishing village next to an unregulated industrial sewage outfall, and haven't gone fishing in their local Liberian-registered-container-ship harbour, and do not even eat the stuff in large amounts daily, poses a risk.
The opinion of the big bad US Government on this subject can briefly be expressed as, um, "no".
And the EPA is, indeed, a bit more stringent on the subject. They say you shouldn't eat more than 12 ounces (340 grams, optimistically evaluated as two meals) of various commonly available fish per week. The FDA, for those who didn't bother to plough through their page, actually says only 14 ounces for persons not currently pregnant, though it says some more soothing stuff first.
I, in my position as Grand Arbiter of Truth for the Whole Planet Earth, think that the five part per million (5PPM, also expressible as 5 milligrams per kilogram) limit for mercury in fish may well allow for considerably higher consumption without any significant risk to non-pregnant humans - but it doesn't really matter whether it does or not, because your fish very probably doesn't have anything like 5PPM mercury in it. Big ferocious fish rhapsodised about by manly men tend to be high in mercury, as of course do those that lived in particularly polluted waters, and it's not a bad idea for pregnant women to be particularly careful. But if you look at what the FDA say about actual mercury levels in most fish available in the USA, you'll note that almost all of them are miles below the 5PPM limit.
(The average concentration of the zillions of different samples on that page is 0.38 parts per million, but that's not a very useful number, because the samples, of various species in various places at various times, are not at proportionally representative of the kinds of fish people eat. The fact that only 402 of the 4456 samples scored over one part per million may be slightly less misleading. Or may not.)
So there's no case to answer. Eat all the supermarket tuna you like - you could do a lot worse.
The Fish Scam people may even be right when they allege that mercury levels in fish, generally (whatever that means), are remaining the same or falling, despite the best efforts of certain people. I can't be bothered tracking down their evidence, though; they refer to three scientific studies, but not in enough detail to make it easy for me to find those studies. (If you have ever written "studies have shown..." and not then given some clues regarding which studies and where, hang your head in shame at your contribution to the incomprehensibility of the universe.)
Not that it'd prove a lot if I found the mysterious studies, anyway; you can find three scientific studies, or nine doctors, to support pretty much any claim you care to make. It's easy to get this sort of thing wrong.
Mind you, the world's fish stocks are falling, so there are fewer old fish being caught. Mercury accumulates in fish, as it does in people who eat fish, as they get older. That's why big carnivorous sea creatures, including whales, are particularly high in mercury. Fewer old fish means lower mercury levels overall - but there's not a shadow of a mention of that possible explanation on the Fish Scam site either.
You may be wondering why the Fish Scam people use a few unidentified studies as evidence, when there's much better stuff out there. The reason is that they just don't like government. Any government. Whatever it does. The FDA may support the Fish Scam arguments, but it must be ignored; lower fish stocks may seem to support their arguments as well, but the fish stocks are low because of inadequate government regulation of rapacious overfishing, so that evidence has to be ignored as well.
The Fish Scam people never shut up about government bodies, definitely including the EPA, which unquestionably do often set risk limits lower than sensibly seems necessary. You're less likely to lose your job for keeping people too safe than for not keeping them safe enough, after all - although Walter Peck probably got quite thoroughly fired. But excessive and/or excessively cautious regulation is the only kind of government action, or information, that the Fish Scam people care about.
Why? Because the fishscam.com domain's registered to the Center for Consumer Freedom. Who are, as appreciators of the art of astroturfing will already be able to recite from memory, "a nonprofit coalition of restaurants, food companies, and consumers working together to promote personal responsibility and protect consumer choices."
Also known as an industry-funded front group.
The CCF may - and indeed, so far as I can see, do - tell the truth about various things on fishscam.com and their several other similarly entertainingly named sites. There's plenty to complain about in popular environmentalism. But, as with all big-name activist groups, the CCF are bullshit artists. Truth or falsity are unimportant to them. Truth might have been important to them once, and they'll take the truth and run with it if it helps them, but the CCF have an anti-regulation, pro-business barrow to push and don't much care how they move it.
Actually, I doubt the CCF was ever interested in truth per se, but various more high-minded activist groups have degenerated into bullshit artists too, because that's what gets the job done.
The CCF just can't agree with the US government, because the government makes regulations, and they're against regulations. They'd undermine their own line of bullshit if they ever said the government did something they liked. Even when it's George W Bush's government we're talking about, for Pete's sake. Oh, sure, the current US regime's not what you'd call a bunch of economic geniuses or anything, but you wouldn't think they could be accused of not giving enough money to deserving businesses.
But no, the 43rd President just isn't pro-business enough, folks. So the CCF still hate the Feds.
(Side-note: Jerry Falwell and Pat Robertson are, similarly, so opposed to those devils at the American Civil Liberties Union that they have been known to claim victory over it even in cases when it was actually on their side.)
To test my theory that the CCF's immutable dogma applies the same sort of weird skewing to everything it does, I headed for the first silly Flash thing I could find on their site, and found myself regaled with the information that the Body Mass Index doesn't work well on very muscular people.
Uh, yeah, that's true. If, as the CCF say, you're built like Matt Damon or Mike Tyson, your BMI will suggest you're obese when you're not. This is not news to people who, um, know something about the BMI, which you may be surprised to learn was not in fact invented by the US Federal Government to oppress the big-boned, but was developed by some guy in a country allegedly called Belgium some time before 1850.
The CCF, which exists to promote the interests of people who make food, are excited about this because it gives them a chance to suggest to the Great American Lard-Ass that his or her BMI of 41 could, actually, indicate 24% better buffness than Arnold Schwarzenegger in his prime.
(Needless to say, the CCF quotes Arnie's BMI from 35 years ago, when he was exercising monomaniacally, taking lots of steroids, and looked like a freakin' Razide. Today his BMI is only about 27, rather than the 34 they quote.)
In other news, Akebono Taro's BMI when he was world sumo champion was around 57. Anything over 25's categorised as overweight; I'm a largely muscle-free male of average height with an entirely unremarkable belly, and so I score 25.9. Personally, I think the BMI's being unnecessarily cruel to me, but I'm not accusing it of inaccuracy when it tells me that I am, indeed, carrying a bit more fat than is healthy.
But because the BMI's a simple height-versus-weight measure, you can get all kinds of peculiar values if you pick on odd-shaped people.
I don't know why the CCF didn't capitalise on this. I mean, if you're very muscular and plump, you can really rack up BMI points. They could emphasise that Sumo wrestlers are PERFECTLY HEALTHY. Just look at what they can do! They're very strong, and they're also very fit (depending somewhat on the definition of physical fitness you use - but yes, Rikishi even go jogging, which is a darned effective way of strengthening your legs when you weigh as much as any two prop forwards).
So, obviously, the wrestlers' tendency to drop dead before the age of 60 must be the result of a government conspiracy.
Regrettably, this conspiracy does not extend to the, um, US National Institutes of Health, who foolishly let slip that you have to have a high body fat percentage, as well as a high BMI, to qualify as obese, and that BMI by itself is just a quick rule of thumb. It's one that works just fine most of the time, of course, because a very small percentage of the affluent world's population has the physique of those who manage to exercise themselves to a high BMI.
The CCF are, by the way, not the only people who've pointed out George W Bush's amazing ability to stay in peak physical condition (with, yes, a misleading BMI of 26) even while dedicating himself so famously to the 24-by-7 workload of the Presidency.
How does the man manage it?
The limited information about BMI's loopholes which the CCF provide is, of course, still of enormous importance to that portion of the world's population that has a six-pack you can scrub clothes on yet knows little about diet and exercise. We should all be very grateful to the CCF for pointing it out so... thoroughly. And for making sure we're all well aware that those Christmas-warring homo-marrying liberals will, any minute now, be making it illegal to sell burgers within a 50 mile radius of a school.
I apologise for the above screed. It's all pretty basic consider-the-source stuff, when you get down to it. But I think it's still worth mentioning, given the amount of minimally attributed pseudo-news that assaults the average occupant of the Minority World these days.
Basic rule: If it's about science, and it's being reported in the popular media, ignore it. It might be right, but it also might be PR balderdash and/or plain old nonsense, and in any case it's almost certainly excessively simplified, leaving not even enough information to give you a clue about where to go to learn the truth.
Those interested in reading about the CCF's activities could do worse than start at PR Watch.
PR Watch are activists too, of course (the site's a project of the Center for Media and Democracy, another triumph in the burgeoning of-course-we're-trustworthy-just-look-at-our-name field), but since the focus of PR Watch's activism is on exposing the (necessarily misleading) activities of the public relations industry, and since they come right out and tell you who they are, who funds them, and what they do, I think they're worthy of rather more respect than outfits whose job is PR.
Particularly when those outfits conceal the identities of their contributors.
To protect them from scary "activists", don't you know.