Thursday, April 5, 2012

Chicken Chemophobia

A recent New York Times Op-Ed spot made the rounds late last night on Twitter. Full of inflammatory language, it seemed wholly bent on scaring the heck out of anyone reading it. The title - "Arsenic in Our Chicken?" - didn't exactly calm me down.

Is this in my chicken? Only very, very little
Well, I'm a scientist, so let's look at this rationally. First things first: here are links to the two papers referenced in the study, one from Environmental Science and Technology (ACS), and one from Science of the Total Environment (Elsevier). (Editor's Note - Whenever a columnist feels pressed to validate his opinion with the words 'published in a peer-reviewed scientific journal,' I turn on the skepticism). 

In both papers, analytical chemists take a peek at feather meal, a poultry industry byproduct, for compounds you might expect from factory farms: antibiotics, stimulants, and antihistamines. A surprise dark horse was encountered in arsenic, which apparently caught everyone so off guard that they required a full second paper to adequately discuss it. 

Glancing quickly at both journals' major tables, it's clear we're talking small amounts here: parts per billion (ppb), which for EST means ng / g, and for STE ug / kg. To put this in perspective, let's imagine we had a swimming pool, which we filled with 1000 L (~270 gallons) of water, which will weigh 1000 kg (density of water = 1 g / mL @ room temp). Now, what's a ppb for this scale? One milligram of material, or about what you'd add if a snowflake fell into your pool.

Better start eating....
Source: Home of Science Wonders
Overall, the article smacks of rampant chemophobia and fear-mongering. While the individual compounds, in acute (high) doses might be cause for concern, the detected values aren't near that much. The LD50 (oral, mouse) for arsenic, the value at which half of tested lab animals die, is 145 mg / kg; the maximum arsenic detected in feather meal = 4 mg / kg! This leap of logic contains an even more far-fetched premise: you'd have to eat two pounds of feathers just to take in that much!

Remember: infinitesimally tiny amounts of several "bad" substances float by you every day, but you don't often see people dropping dead.

Maybe that's the reason that this NYT reporter buries his lede - a quote from his source, Dr. K. Nachmann, an author on both papers: "We haven't found anything that is an immediate health concern." 

And look, now I've gone and buried it, too.

(Update, 12:09 4/5 - Commenters on Twitter point out that a topic I did not address - detection of banned antibiotics - could be cause for concern. I agree with that point)


  1. one of the questions that could be of some use, is to do some chelation studies for arsenic in vegetarians vs meat (chicken) eaters- and combining this with a questionaire on presence of chronic illness. Given that we are exposed to numerous toxicants over long periods of time, from infancy, the notion that these "miniscule" amount pose no threat may be incorrect - LD50 really has only to do with acute toxicity- not long term, accumulative. And certainly , does not take into account individual differences in the genetics of our abilities to detoxify these substances which can interfere at cellular levels.

  2. Remember: infinitesimally tiny amounts of several "bad" substances float by you every day, but you don't often see people dropping dead.

    Rigghhhttt...because the incidences of cancer are dropping in this country. Autism rates up 78% in the last decade...but NO, it's never a chemicals fault...

    How much mercury does it take to poison that swimming pool Doc?

    Everyone should be concerned about the chemicals in their food - everyone. It doesn't take a degree in chemistry to figure out there is a correlation between illness and the rise of additives in our food and water supply not to mention the toxins in the air we breathe.

    I studied agriculture in college and have none of the misconceptions about farming or fear from ignorance. I do have a healthy skepticism for the use of chemicals in what goes into my body as anyone should.

    If you're trying to make an intellectual based point here you failed miserably...

    1. totally agree - awful counterpoint

    2. "because the incidences of cancer are dropping in this country"

      American cancer researcher here. The prevalence of most kinds of cancers ID dropping in this country.

  3. Thank you! Fears in the general public seem to be expanding rather than contracting: most people I know are terrified of bacteria, chemicals in our food, cholesterol (which we've had to simplify to "good" and "bad"), and more. The goal of science is to expand human knowledge. A logical outcome of that knowledge would be less fear, not more! Scale is critical, and people seem to forget that we routinely get exposed to all kinds of things that could kill us... yet, here we are. We DO have coping mechanisms. It probably could increase our risks of cancer, but so does breathing. Is this more or less than you would encounter during a normal day? And just how much feather meal are most people exposed to (daily, yearly, or cumulatively over a lifetime)? These are things to keep in mind when reading any sensationalist news story. There is RADIOACTIVITY in your chicken, too!

  4. Just a lay person here: Could it be that the levels in the feathers represent a larger level in the body of the bird? Also, the most concerning item for me is that they are using illegal antibiotics such as Cipro and getting away with it. What do you think about that?

  5. Mmm, so if I eat my weight in chicken in a year, I'm only at 3% of what should kill me. So very re-assuring!? And that's just *one* source of all these supposedly safe chemicals.

  6. there is countless studies/data that show a direct correlation to quality food/diet and chronic illness like heart disease and cancer.

    Your response is reckless and poorly written. It follows no logic. If there is no harm with any of these chemicals used by Big Agro, who do they spend hundreds of millions of dollars each year ensuring Congress doesn't pass legislation that would mandate labelling that explicitly says what goes into our food?

  7. @Anon7:48 - Good idea on the chelation analyses. I agree that long-term exposure warrants further study, but since this data comes from feather waste (which we don't eat) and not specifically meat, it's somewhat misleading. Also, the arsenic detected was predominantly in inorganic salt forms, and not as organoarsenics, which are much more bioactive.
    @Anon7:55 - I'm as skeptical as you, but I wait to see real data, not scary headlines adapted from unrelated exposures. Sorry that my piece did not meet your expectations.
    @Katana - Thanks! I agree with you completely.
    @MG - Could be, but the jury is still out...last year, the FDA copped to a small amount of arsenic detected in livers of birds who had received specific drugs, but it was unclear what levels were found in meat. Regarding the 'illegal' antibiotics, perhaps the best way to combat this is more thorough inspections or prosecution for repeat offenders. As you've pointed out, the most likely way for these compounds to enter the tissues is through their feed or water.
    @Anon8:16 - Touche. And I've NEVER indicated that these chemicals are "safe." Anything can sicken you, given a high enough dose, but my point remains that these levels are too small for that to occur. Plus, we don't eat feathers!

  8. @Saagar8:42 - I'm sorry you dislike my writing style, perhaps you'd like to offer me some pointers?
    Despite commenting about the logic of my post, you've not considered the logical thread of your own: in one fell swoop, you've jumped from clinicals to disease, to critiques, to corporations, to lobbyists.
    Yet, none of this addresses the papers, detection limits, or suggests a single solution or way forward.
    Here's an editorial comment: rework, and resubmit.

  9. A little here from foods.and a little there from our beauty products and more from our water and air

  10. Maybe I am mislead by my education, but I seem to recall that the human body does not "clear" arsenic and that all exposures are cumulative. The CCA treatment of wood products a while back showed that repeat exposure greatly increased the risks from the original findings that the levels were low enough to be safe. After years of working with these products, OSHA came out with a list of new guidelines for workers like me that boiled down to avoiding hand to mouth exposure, no burning of scraps, and that the products must be sealed after installation because of contact exposure to the customer and anyone touching the bare product for years after installation. The vastly increased consumption of chicken in the US today would indicate REPEAT EXPOSURES that would be a cumulative exposure to me.

  11. Seriously, you are using LD50 as the basis for what is healthful exposure? LD50 is about acute toxicity, what will *kill* test animals from a single exposure. It is essentially *useless* in determining the danger of long term exposure, particularly when we are talking about heavy metals like arsenic that build up in the body over time. Your use of it here shows your lack of seriousness, and ignorance of basic biological science. The question is not whether that chicken is going to kill you today, it is whether it will cause cancer or a whole host of other diseases years down the road.

    Chemist, meet Biologist. Please stick to chemistry or do a little more reading. "I'm a scientist" does not mean you get to run your mouth in areas where you are clearly ignorant.

  12. Thanks, I feel much better now knowing that the arsenic, caffeine, acetaminophen, Benedryl and the like being added by big agriculture to chicken feed only leaves trace amounts in chicken feathers.

    Why they are at it, why not supply the poor chickens with some nicotine, valium, or cocaine? A stiff drink or two might not be a bad idea. Or, perhaps trace amounts of cyanide or strychnine will also be found to yield some benefits for achieving faster weight gain. If so, toss them in as well.

    Or, perhaps, we could just feed chickens a diet that, you know, they evolved to eat. Just a thought.

  13. While scientific study of this is worthwhile, I'm not so sure it behooves the general public to wait until a causal link between a single source of exposure and subsequent health problems is established. Given that we are constantly being exposed to chemicals from thousands of different sources throughout any given day, that link might never be proven. Even if chicken consumption, for example, DOES impact our probability of negative health consequences, it could be near impossible to prove given the small amount of exposure from a single source.

    Given all that, it's not an irrational choice to attempt to cut down on daily exposure to even tiny doses of harmful chemical exposure where possible just because it's not scientifically proven to harm us. For many of us, given the unlikely prospects of rigorous scientific study of this any time soon, the problem isn't that we can't prove that it hurts us but that we can't prove that it doesn't.

  14. @Anon9:23 - Yes, they certainly do. But where, and how much? In what tissues? Creating what health effects? Please, send me your data.
    @Mark - Again, results for actual levels of compound found in the muscle tissue / meat of the chicken are mixed. This story used only data from feathers, which people don't eat. Also, regarding arsenic treatments in wood, the exposures were orders of magnitude above these:
    @Anon9:58 - Chronic exposures do bioaccumulate, I'm not claiming that they don't. But ppb? In feathers? I'm not drawing up carte blanche for industry here to add anything they want, I'm simply stating that articles in major news articles have a responsibility to not inflame the public for misinterpreted data. Note, also, that I mention LD50 was for acute exposure pretty clearly. Again, show me the data that proves the chicken feather -> human disease route.
    @Anon9:59 - Agreed. Factory farms do not feed the evolutionarily preferred chicken feed. Congrats on my wittiest comment yet.

  15. @Anon10:08 - Thanks for the well thought-out comment. I appreciate it.

  16. @See Ar Oh from Anon 9:58
    Sorry, no, the onus is not on me to prove it's not OK to add a *known* poison and carcinogen to our food supply (just read that contorted sentence to see how silly it sounds). The onus is on the people adding the known poison and carcinogen to show that it *is* safe. That it is legal to give arsenic to chickens is shocking, and definitely legitimate news.

  17. The human body does clear arsenic; the half-life for inorganic As is on the order of days. (based on a quick search)

    1. Seems reasonable. I mean, if you can detect As, Pb, Cd in hair, there's one escape route, right there!

  18. Great post! had not seen the NYT article until now

  19. I think you should talk about arsenic found in rice, because that may actually affect humans, especially ones who eat lots of it. I can dig up some articles I was reading a few weeks ago.

    PS: I will keep chicken feathers out of my diet from now on.

  20. What is stranger for me is the authors and many of those commenting on the article advocate that eating organic food or adherence to a vegan diet as a solution to this problem. However, the primary use for chicken feather meal is as organic fertilizer (non-organic farming has the option of using purified or synthesized chemicals instead of animal waste). So, being a vegan isn't going to save you here, and eating organic, ironically perhaps, is more likely to result in exposure to the substance in question.