The dose makes the poison

One of the most fundamental concepts in pharmacology and/or toxicology is the dose-response curve, which gives a graphic representation of how the human body responds to varying doses of chemicals.  Something that is often poorly understood by laypeople, but becomes obvious if you study the topic at any length, is that there are some substances (e.g. lead) which are unsafe at any dose, and others that are necessary at low doses but toxic at high ones (e.g. table salt).  Further complicating the matter is that some substances bioaccumulate -- small doses over a long period of time can cause a toxic increase in the body tissues.  Elemental mercury, for example, doesn't get excreted readily, so even small amounts over a long period can result in harm (giving rise to "mad hatter syndrome" if sufficient quantities are ingested).  Others are water-soluble and quickly cleared by the kidneys, so it takes a great deal more to result in harm (e.g. vitamin C).

[image courtesy of the Wikimedia Commons]

So the subject isn't simple.  But if you're going to read anything on toxins and (especially) vaccines, you damn well better do your homework, or you're likely to get suckered by articles like the incredibly bullshit-dense "The 7 Most Dangerous Vaccines Injected Into Humans and Exactly Why They Cause More Harm Than Good" that appeared over at Natural News a few days ago.

The article, written by S. D. Wells, would be the same tired old "chemicals = bad" nonsense trotted out by damn near everyone in the alt-med world, from Vani "Food Babe" Hari to Mike "Health Ranger" Adams, except for the fact that Wells starts going into specifics about which chemicals in vaccines are bad, why, and at which doses.  Which is unfortunate for Wells, because any time these people slide over into analysis of the facts, they immediately start making claims that anyone who passed high school chemistry would know immediately are false.

Let's start with my favorite line in the whole thing, which is how the MMR (measles, mumps, rubella) vaccine contains sodium chloride, which "raises blood pressure and inhibits muscle contraction and growth."  Yes, sodium chloride, i.e., plain old table salt.  He also tells us that another vaccine, Gardasil, contains this dreaded toxin at nearly 10 micrograms.  If you can imagine.

For comparison purposes, the Recommended Daily Allowance for salt is 4 grams.  To save you from doing the math, this means that the Gardasil vaccine contains 1/400,000th of the salt you ordinarily get from your food.

But in the words of the infomercial, "Wait!  There's more!"  Gardasil also contains 35 micrograms of sodium borate, which Wells tells us is a chemical used to kill cockroaches.  What he doesn't tell us is that borate is another micronutrient in the human diet, and is only toxic at huge doses -- at least huge compared to what's in Gardasil.  Again consulting the Recommended Daily Allowance tables, the RDA for boron is 1 to 6 milligrams -- about a hundred times what you get from Gardasil.

Wells doesn't just mislead and/or lie outright about the chemical constituents of vaccines, he lies about their side effects.  Gardasil, we're told, has horrific results; he says, "many girls who get the HPV vaccine beginning at age 9 for a sexually transmitted disease (diseases they dont [sic] have) go into immediate anaphylactic shock and some into comas and die."  Which is simply untrue; a study in 2012 of 189,000 girls who had been inoculated with Gardasil showed that the most common side effect was same-day syncope (i.e., they fainted), and even that was uncommon.  If that's not enough, a study of a million girls in Denmark was so side-effect free that the authors concluded that there was “no evidence supporting associations between exposure to qHPV vaccine and autoimmune, neurological, and venous thromboembolic adverse events."

But back to Wells.  Another horror he trots out is monosodium glutamate in the MMR vaccine.  If you're wondering if this is the same chemical that's used for a flavoring in Chinese food, yup, that's it.  It's also the sodium salt of one of the most common naturally occurring amino acids, and is found in tomatoes and cheese, not to mention General Tso's chicken, in quantities that are orders of magnitude more than are in the vaccination.  Then we have polysorbate 80, which Wells claims causes sterility even though it's used as an emulsifier in ice cream and a study on rats who were fed polysorbate 80 at a quantity of 0.5% of their body weight per day showed no adverse effects whatsoever.

I did get a good belly laugh at Wells's horrified statement that the swine flu vaccine contains "inactivated H1N1 virus."  After I finished laughing, I shouted at the computer screen, "How the fuck do you think vaccines are made, you nimrod?  What do you think they contain?  Holy water and magic berries?"

Then we have the wizened old claims about vaccines and mercury, even though the only vaccines that still contain thimerosal (a mercury-based stabilizer) are multivalent flu vaccines, and the stabilizer breaks down quickly to ethylmercury which is quickly cleared from the body by the kidneys.  (A lot of the confusion over mercury toxicity comes from mistaking this compound for methylmercury, which is toxic, bioaccumulates, and causes progressive nerve damage.)

And so on and so forth.  It's the same old, same old, really, but this was such an amazingly dumb example of anti-vaxx rhetoric that I thought it worth debunking.  As for me, I'm going to go look up the dose-response curve for bullshit, because I think reading Wells's article may have given me a fatal dose.

Yes, we have no bananas

Yesterday a student asked me, "Is it true that you can die from eating too many bananas?"

I responded, "You can die from eating too much of anything.  How many bananas are we talking about, here?"

She said, "Seven, is what I've heard."

That sounded pretty unlikely to me, and I said so.  "What about eating seven bananas could be dangerous?"

"You'd die because so much potassium would be toxic," she said. "My brother told me he heard that from a friend."

Sketchier and sketchier.  One of the functions of your kidneys is to keep the levels of sodium and potassium in your blood within an acceptable range, and I couldn't imagine that a few too many pieces of fruit was all it took to overwhelm the system.  So I said I still thought it seemed implausible, but told her I'd look into it.

And lo, it turns out that this claim is making its way around.  In fact, BBC News Online ran a story just a few days ago entitled, "Can Eating More Than Six Bananas at Once Kill You?"  And this once again illustrates the truth of Betteridge's Law, which says that "Any headline that ends with a question mark can be answered by the word no."

[image courtesy of the Wikimedia Commons]

The most bizarre part about all of this is that it was stated, right there in the article, that the origin of the urban legend (if I can dignify it even with that name) was British actor and comedian Karl Pilkington, who made the statement in a conversation with fellow comedians Ricky Gervais and Stephen Merchant.

"Before when you were talking about bananas," Pilkington said, "I had that fact, about if you eat more than six, it can kill you.  It is a fact.  Potassium levels are dangerously high if you have six bananas...  I saw a bowl of bananas.  There's six bananas there.  You know why there's only six?  Seven would be dangerous."

And for some reason, enough people didn't know he was joking that the whole thing has now gone viral.

Can I remind you once again that Pilkington is a comedian?  I.e. a person who makes a living exaggerating the truth, or simply making shit up, to be funny?

And the BBC News Online is not helping.  Although later in the article they do quote Catherine Collins, a dietician at St. George's Hospital in London, who confirmed that seven bananas isn't going to kill you, there is an unfortunate tendency of people to read only the headline and the first couple of paragraphs of an article and decide that's all they need to know.  And by the fourth paragraph, you're still left thinking that your life is in danger from Toxic Death Bananas.

"It would be impossible to overdose on bananas," Collins said, way down near the end of the article.  "You would probably need around 400 bananas a day to build up the kind of potassium levels that would cause your heart to stop beating."

Well, I'm no dietician, but my general impression if that you eat 400 bananas in a single day, you're going to have way more problems to worry about than potassium toxicity.  And given that she phrased it this way, I'd be willing to bet that even amongst the readers who got this far in the article, there were still some who read Collins's statement and focused only on the words "EAT BANANAS POTASSIUM HEART STOP BEATING" and missed entirely the words "impossible to overdose."

So thanks to an offhand comment from a comedian, we now have another loopy idea to add to the list, joining ones like Daddy Long-Legs Are Deadly Poisonous But Have Weak Fangs, and Don't Throw Rice At Weddings Because Birds Will Eat It And Then Explode.

In short: there is no reason for bananaphobia.  Seven seems excessive, honestly, but if you'd like to pig out and eat the whole bunch, have at it.  And the other takeaway is: don't learn your science from comedians.  They lie sometimes.

Smoke screen

When evaluating a claim, it's often as important to recognize which questions to ask as it is to understand the science behind the claim itself.  What information did the author leave out -- intentionally or unintentionally?

The reason this comes up is an online article sent to me by a loyal reader of Skeptophilia entitled, "Studies Reveal 'Smudging' Eliminates Dangerous Bacteria in the Air."  The article describes the practice of "smudging," the burning of sweet-scented dried plants, and claims that the smoke is beneficial because it kills bacteria.  (S)he cites an earlier study, published in 2007 in the Journal of Ethnopharmacology, which has the following passage:

We have observed that 1 hour treatment of medicinal smoke emanated by burning wood and a mixture of odoriferous and medicinal herbs (havan sámagri=material used in oblation to fire all over India), on aerial bacterial population caused over 94% reduction of bacterial counts by 60 min and the ability of the smoke to purify or disinfect the air and to make the environment cleaner was maintained up to 24 hour in the closed room.  Absence of pathogenic bacteria Corynebacterium urealyticum, Curtobacterium flaccumfaciens, Enterobacter aerogenes (Klebsiella mobilis), Kocuria rosea, Pseudomonas syringae pv. persicae, Staphylococcus lentus, and Xanthomonas campestris pv. tardicrescens in the open room even after 30 days is indicative of the bactericidal potential of the medicinal smoke treatment.  We have demonstrated that using medicinal smoke it is possible to completely eliminate diverse plant and human pathogenic bacteria of the air within confined space.

So far, so good.  Assuming that the experiment was well-controlled and that there were no obvious design flaws invalidating the results, getting rid of pathogenic bacteria is certainly a good thing.  The author of the first article sums up thusly:

The basic concept is that by burning particular plants parts and resins, the energetic blueprint or spirit/intelligence of that plant is released, producing a medicinal smoke.  The smoke is then utilized to cleanse the energy of individuals, groups, spaces or object.  Herbs like Sage, Palo Santo, Copal, and Sweet-grass are common smudging herbs that are widely used for healing and to remove unwanted energetic and spiritual buildup and also to instill blessings...  Thanks to this amazing study we now know that smudging with sacred herbs is not only soothing to the mind and spirit, it is affecting the health and even safety of the actual environment in which it is done.

Setting aside the whole "energetic blueprint" and plant intelligence nonsense, there are a few questions that come to my mind that neither the author of the original study, nor the author of the post lauding its results, thinks to ask:

1. How many pathogenic bacteria were in the room to start with?  All we're given is the percent reduction (94%), which sounds like a lot -- but 94% of a tiny amount is an even tinier amount, and neither is significant.
2. If there are chemicals in smudging smoke that kill bacteria, could those chemicals be toxic to humans as well?  I'm reminded of all the articles that get passed around saying, "Substance X (usually some naturally-occurring compound) found to kill cancer cells!" -- and it turns out that yes, the substance kills cancer cells, but in vitro.  Whether it kills cancer cells in a human body, and does so without killing the human, remains to be seen.  After all, consider the fact that pissing in the petri dish will probably also kill cancer cells in vitro.
3. Are there other chemicals in the smoke besides the bacteria-killing ones that might be harmful?  In general, it seems like inhaling smoke of any kind is a bad idea.

So let's look at these questions one at a time.

For the first question, there were a lot of hyped-up articles like "There's a Time Bomb Ticking in your Household Dust" that presented a lot of scary stuff (like electron micrographs of dust mites, which look like a cross between a crab and that thing that burst out of the dude's chest in Alien) but little in the way of verifiable detail.  I did find an interesting article by Dr. Harriet Burge, director of aerobiology for EMLab P&K, a New Jersey-based indoor air quality assessment lab, and she had the following to say:

I generally do not recommend bacterial analysis of house dust except in a few unusual situations.  This is because we don't know how to interpret the results.  However, we do receive occasional requests for cultural bacterial analysis of house dust.  These analyses are done by dilution culture and data can be presented as total bacteria, general groupings of bacteria (i.e., Gram negative, Gram positive, Bacillus), sewage screens (total coliforms, Enterococcus, etc.) or species identification for the most abundant colonies.  Sewage screens usually involve presence or absence in house dust.  Otherwise, interpretation is based on the number of colonies present per gram of dust, and/or the relative composition of specific bacterial groups or specific organisms in the dust. 

Given that these requests are not rare, it seems appropriate to develop some interpretation guidelines, at least with respect to average or "usual" populations in house dust.  Unfortunately, few studies have been done documenting concentrations of total culturable bacteria or of any specific organism or group of organisms.  In my experience, these studies are rarely done because the dynamics of exposure to house dust are not clear, and because dust is not considered to contain human pathogens (or at least dust is not considered the primary source for human pathogenic bacteria).

So given that household dust isn't the most common source of transmission for human pathogens, it's unclear whether sterilizing the room would, under most conditions (i.e. we're not talking about an operating room here), lower the incidence of disease.

[image courtesy of photographer Christopher P. Michel and the Wikimedia Commons]

On to the second and third questions, which are related.  On a quick search, the first thing I turned up was a paper from Clinical and Molecular Allergy by Ta-Chang Lin, Guha Krishnaswami, and David S. Chi entitled, "Incense Smoke: Clinical, Structural, and Molecular Effects on Airway Disease" which had the following to say:

Incense smoke (fumes) contains particulate matter (PM), gas products and many organic compounds.  On average, incense burning produces particulates greater than 45 mg/g burned as compared to 10 mg/g burned for cigarettes.  The gas products from burning incense include CO, CO2, NO2, SO2, and others.  Incense burning also produces volatile organic compounds, such as benzene, toluene, and xylenes, as well as aldehydes and polycyclic aromatic hydrocarbons (PAHs).  The air pollution in and around various temples has been documented to have harmful effects on health.  When incense smoke pollutants are inhaled, they cause respiratory system dysfunction.  Incense smoke is a risk factor for elevated cord blood IgE levels and has been indicated to cause allergic contact dermatitis.  Incense smoke also has been associated with neoplasm and extracts of particulate matter from incense smoke are found to be mutagenic in the Ames Salmonella test with TA98 and activation.

So there's that.  I tried to find any studies of white sage (Salvia apiana) and sweetgrass (Hierochloe odorata) -- two of the most common plants in smudge sticks -- to see if either had been studied for toxic effects.  Nothing turned up.  There was lots of stuff about expelling negative vibrations, however.  So this one falls into the "we don't know" category.

On the other hand, it's pretty clear that smoke in general -- even wood smoke -- shouldn't be inhaled.  Incompletely-burned plant material contains polycyclic aromatic hydrocarbons, organic compounds that have been identified as not only carcinogenic and mutagenic, but also directly toxic.

So in the end, we're left with more questions.  On the one hand, incense and smudging smoke smells good and seems to kill nasty bacteria, which is good.  On the other, the bacteria that it kills almost certainly would never have made you sick in the first place, and the smoke is also potentially dangerous for you to inhale, which is bad.  In the final assessment, smudging your house if you have adequate ventilation is probably not going to hurt you, but isn't really going to do much to help you, either, unless you believe in "negative vibrations."

And in the even-more-final assessment, what we really should be doing, even more than burning dead plants in our houses, is asking questions.  Not simply buying whatever you read at face value -- in other words, recognizing that there are questions to be asked -- is the first step.

Crayons, asbestos, and risk

Let's have a little chat about the topic of risk.

It's something that a lot of people don't understand, but in principle, it's a simple concept.  Actuaries, and other folks who get paid to think about such things, define risk as the product of two probabilities: the probability of exposure and the probability of harm.

The problem is that misassessment of one or both of these two probabilities leads people to (in some cases) wildly overestimate the risk of certain behaviors, and (in others) to wildly underestimate it.  Often, these misassessments have to do with the familiarity of something -- familiar, everyday things are usually considered safer than they really are, and unfamiliar ones more dangerous, regardless of whether those perceptions are at all rooted in reality.

Dan Gilbert, in his wonderful TED talk "Why We Make Bad Decisions," illustrated this perfectly with a photograph of a burning skyscraper, a plane crash, a terrorist bombing site, and a swimming pool.  He then asked the audience to play the Sesame Street game of "Which Of These Things Is Not Like The Other?"  "If you chose the swimming pool, you're correct," Gilbert said.  "Because of the four, it's the one that is by far the most likely to kill you."

This becomes even worse when we start looking at the risk of "chemicals."  I put the word "chemicals" in quotation marks, because of course, everything is made up of chemicals.  (I once saw a sign for "U-Pick Organic Chemical-Free Strawberries."  Ponder that one for a while.)  The problem is, lots of people don't understand chemistry, and so anything with a fancy-sounding name immediately gets put in the "unfamiliar/dangerous" column, even if it's a perfectly innocuous compound, or even one that is essential for life.

Even dangerous chemicals, of course, don't necessarily act straightforwardly.  It's not enough to say that a compound is toxic -- you also have to ask how likely it is to get inside you and cause trouble, and whether the dosage you're being exposed to is, in fact, dangerous.  It's why all of the panic earlier this year about "radioactive water from Fukushima" being detected on the shores of western Canada was unfounded -- the radioactive isotope detected, cesium 134, was only discovered because it's unlikely to get into seawater any other way.  Jay Cullen, oceanographer at the University of Victoria, said, "We're more than a thousand-fold below even the drinking water standard in the coastal waters being sampled at this point.  Those levels are much much much lower than what's allowable in our drinking water."

So the dosage was far smaller than our daily exposure to naturally-occurring sources of radiation, and would be entirely harmless even if we were drinking seawater, which most of us don't.  But it didn't stop people from freaking out completely about how we were being poisoned, irradiated, and (of course) all gonna die.

A more recent goofy claim that has the interwebz in a tizzy lately is the claim that asbestos has been discovered in crayons.  Asbestos, of course, is one of those words like "radioactivity" -- all you have to do is say it and people start thinking they're being killed.  In fact, the danger of asbestos for most people is minimal -- the majority of the asbestos that's still around is safely locked up in wall board and ceiling tiles.  It's only when asbestos-containing materials get broken up, and the dust produced that way is deeply inhaled, that it increases one's likelihood of getting certain lung cancers, such as mesothelioma.

So what about the asbestos in crayons?  First of all, there's the difficulty in telling apart asbestos fibers from talc.  Talc, a chemically related mineral, is used in all sorts of things, up to and including baby powder.  You also don't want to inhale talc -- but the same could be said for any finely-powdered mineral.

[image courtesy of the Wikimedia Commons]

Second, even if there was asbestos in crayons, could it hurt you?  The answer is "almost certainly not."  All the way back in 2000, the Consumer Product Safety Commission was prompted to do an analysis of crayons, and found "a trace amount of asbestos in two Crayola crayons made by Binney and Smith and one Prang crayon made by Dixon Ticonderoga" but stated that "the amount of asbestos is so small it is scientifically insignificant."  Add that to the fact that this "scientifically insignificant" quantity of asbestos is bound up in the colored wax that makes up the rest of the crayon, so the likelihood of inhaling it is nil, and you have what is commonly called a "tempest in a teapot."

Snopes put it succinctly: "In other words, if trace amounts of asbestos were encased in a waxy substance such as crayons, those fibers would not be friable and would pose no risk of becoming airborne."

It'd be nice if more people would learn about risk and toxicity -- not only would it get them to calm down about the stuff they're exposed to on a daily basis, most of which their bodies handle just fine, it would also stop people from forwarding ridiculous claims on Facebook and Twitter, which is getting to be annoying.  In any case: don't worry about letting your kids use crayons.  Coloring in a coloring book is not going to give them lung cancer.  All you have to do is make sure that they aren't grinding up their crayons and snorting the powder.

But I'm hoping you'd do that in any case.

Don't drink the water

So, in our last installment of Learning About Chemistry From People Whose Last Science Class Was In The Seventh Grade, we found out that breathing air causes all of the diseases known to man.  Today we will hear about how drinking water is slowly killing us all.

Man, with all of the air we breathe and water we drink, it's a surprise that the human race isn't extinct by now.

This latest sermon from the Church of Wingnuttery ties into the whole anti-fluoridation movement.  You probably are aware of the controversy surrounding fluoridation of water to prevent tooth decay; despite multiple peer-reviewed studies that have shown that this is safe and effective (read two of them here and here), there are people who think that fluoridation is basically the government's way of slowly murdering us all.  (Of course the government wants to kill all of its citizens.  Don't make me use the word "sheeple" in your general direction.)  Further, because of the presence of fluoride minerals in soils and bedrock, fresh water is naturally fluoridated, with a concentration averaging around 0.2 ppm.  Seawater has concentrations ten times higher than that, and aquatic animals seem to be able to tolerate it just fine.

So, fluoride is pretty safe, in low doses, and will save you the cost and trauma of multiple trips to the dentist.  But don't take my word for it.  Don't take the scientists' word for it, either.  No, instead, you should trust the likes of "April," who wrote an article for the website Starseed411 called "How Does Your Drinking Water Affect You?" that should be inscribed forever in the annals of Making Shit Up.

April starts out with a chemistry lesson:

We have all known all our lives that our drinkng [sic] water supply is H20, 2 parts hydrogen and 1 part oxygen. There is an old book called Natural Philosophy by: G.P. Quakenbos, A.M., entered according to act of Congress in the year 1859, by G.P. Quakenbos, the Clerk Office of The District Court of The United States, for the Southern District of New York. This book states that towards the end of the 18th century water was found to be a compound substance made up of a combination of oxygen and hydrogen, combined in the proportion of 1 to 8. Meaning 1 part oxygen and 8 parts hydrogen. H80.

I knew it!  I knew there was something wrong with my well water!  It just isn't hydrogen-y enough.

So, anyway, if water is supposed to be eight parts hydrogen to one part oxygen, how did it end up as familiar old H₂O?

The answer, of course, is fluoridation:

Fluoride was infused into the water to destroy and remove 6 parts hydrogen. Our water supply affects us by hardening our pineal gland, by age 12 the pineal gland is calicified [sic], and by adulthood it is atrophied.

That nasty old fluoride!  Stealing away 75% of the hydrogen from our water, and hoarding it all for itself!  And making our pineal glands go all... crusty.  Terrifying!  But what effects does this have, and what can we do about it?

The pineal gland (third eye) is the seed of our soul and our connection to the spiritual, physical world, and higher frequencies. This gland is our power source. The pineal gland is like a built in wireless transmitter. when the pineal gland becomes awaken, learning abilitys are heightened; enhanced creativity; intuition; triggered psychic abilities, and experience bliss. Fluoride in the drinking water seals these capabilitys [sic]. You can awaken your pineal gland through eliminating bad sugars, processed foods, and fluoride from your body.

Well, that explains why I've experienced so little bliss lately.

Now, lest you think that "April" is just one aberrant wacko, take a look at the highly scientific editorial "Water is Poison" (gist: fluoride rots your bones, destroys your immune system, and is being used by the government for purposes of "eugenics"), not to mention "Fluoride: The Lunatic Drug" (which reads like a compendium of anti-scientific craziness ranking right up there with the best of David Icke).  The upshot: fluoride doesn't prevent cavities.  It causes cancer, osteoporosis, Alzheimer's disease, and kidney problems, not to mention making you "stupid, docile, and subservient."

In any case, let's clear a few things up.  Fluoride, in the miniscule doses you'd get from either naturally or artificially fluoridated water, is completely harmless, and has little other effect than strengthening your tooth enamel.  This has been repeatedly demonstrated to the satisfaction of panels of scientists trained in human physiology.  Of course it's poisonous in large doses; so are a great many other things, including caffeine, aspirin, and table salt.  If you don't understand how this works, there's this thing called a dose-response curve that you might want to investigate that will hopefully clarify the point.

Also, it bears mention that if fluoride is as horrible as these people claim, there should be a fairly strong correlation between living in a community that fluoridates its water and terrible health.  So, take a look at this map, from the National Center for Health Statistics:

Percentage of communities, state-by-state, that fluoridate their water

So, from this map, we should expect the greatest number of sane and healthy people should be in states like New Hampshire, and that the citizens of New Mexico should be... worried.  But take a look at this map of cancer incidence, from the Center for Disease Control:

Do the words "no correlation" mean anything to you?  And none of the other diseases the anti-fluoridation crowd wants to attribute to fluoride in the water -- Alzheimer's, osteoporosis, type-2 diabetes, and kidney failure -- show any greater degree of correlation.

Unfortunately, I wasn't able to find maps showing the incidence of being "stupid, docile, and subservient."  Maybe the Center for Disease Control isn't putting that data out there because it's too damning, I don't know.

Anyhow, that's about all I have time for today.  It's amazing to me that there are people who swallow this stuff (figuratively speaking; I hear that anti-science nonsense is toxic in high doses!).  But judging by the controversy that erupts every time a community puts fluoridation up to the vote, apparently there are a great many people who aren't swayed by research, and instead are convinced by alarmist rhetoric.  I suppose I can't do much about that, but I do hope that they have their dental insurance paid up.