Exercise Your Way to an Easier Pregnancy — Guest Post at What To Expect

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Me, cross country skiing at 8 months pregnant. Super awkward, super fun.

Woohoo! I was asked to guest post for the “Word of Mom” blog at the What To Expect When You’re Expecting website! At the request of a friend, my article was about what the science shows regarding exercise and pregnancy. Here’s a very brief summary of my findings:

  1. Listen your body; it will help you find the right effort level for safe pregnancy exercise.
  2. Women who exercised hard before pregnancy can likely continue to do so during pregnancy without trouble, but competitive athletes should talk to their obstetrician about their pregnancy fitness goals, and may require monitoring.
  3. Even if you weren’t much of an exerciser before pregnancy, there’s no time like the present.
  4. If you’re not a fan of the treadmill or weight room, consider water aerobics or yoga!
  5. It’s a good idea to run your exercise and activity plans by your obstetrician to make sure they’re safe.
  6. If anything unusual or concerning happens during or after a workout, call your OB.

You can read the whole article here on What To Expect.


AAP Takes a Strong Stance on Recess

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W and a friend engaging in some unstructured play.

In a recent policy statement, the American Academy of Pediatrics (AAP) extolled the virtues of recess as an invaluable part of the school day. With pressure on schools and teachers to produce children who excel scholastically (or who, at the very least, can pass standardized tests), the focus in the classroom is increasingly an academic one. Unstructured play time, whether in the classroom or outdoors, is becoming increasingly rare just as studies increasingly demonstrate its importance.

Reduced recess time does children a disservice, explains the AAP, and not simply because increased physical activity is associated with healthier body weight. In fact, it appears that recess is more than just an opportunity to get some exercise, and while a structured physical education class is an important part of the academic curriculum, it’s not a substitute for unstructured play time. An article by Ramstetter et al reviewed a host of studies on the benefits of recess, concluding that periods of unstructured play throughout the school day provide benefits for mental, emotional, physical, and social development. Further, a variety of studies have demonstrated that children benefit from regular breaks from academics, and recesses throughout the day allow children to focus better once they return to the classroom (see, for instance, Ginsberg et al. Jarrett et al, Stellino et al).

It appears that it’s not just young children who benefit from regular recess; adolescents also demonstrate increased performance, enhanced concentration, and better behavior when they’re allowed a break between mental tasks. Unfortunately, though, unstructured recess time in schools dwindles as a child ages, with most or all of a middle- or high school student’s day devoted to academic tasks.

With regard to the timing of recess, typical elementary schools offer play time after lunch. Studies suggest, however, that offering children an opportunity to play before they eat increases the time and attention they pay to their food, improves nutritional intake and mealtime behavior, and improves classroom behavior after lunch (see, for instance, Bergman et al, Gettinger et al).

On the basis of their review of the evidence, the AAP Policy Statement recommendations include the following:

  • Recess is an important part of the school day, and institutions should not withhold recess to punish poor achievement or misbehavior. Neither should academics be allowed to replace recess in the school day (as this is counterproductive).
  • Because it allows for mental decompression and de-stressing, recess is equally important to younger children and adolescents.
  • While physical education is a valuable part of the school day, it should not be considered a substitute for recess. The former is academic in nature and can teach healthy habits, but only the latter allows for unstructured play and the fostering of creativity and social skills.
  • Children given the opportunity to engage in active, unstructured recess are more likely to meet the (AAP’s) recommended 60 minutes of physical activity each day; this helps to combat obesity.
  • Schools should strive to provide a safe, supervised recess environment. The AAP recommends that schools ban unsafe games or activities, but strongly recommends against banning or restricting recess on the grounds that children might engage in dangerous activities.



AAP Council on School Health. The crucial role of recess in school. Pediatrics. 2013 Jan;131(1):183-8.

Bergman EA, Buergel NS, Englund A, Femrite T. Relationships of meal and recess schedules to plate waste in elementary schools; University of Mississippi, National Food Service Management Institute. 2003.

Gettinger et al. Food waste is reduced when elementary-school children have recess before lunch. J Am Diet Assoc. 1996;96(9): 906–908

Ginsberg et al. The importance of play in promoting healthy child development and maintaining strong parent-child bonds. Pediatrics. 2007 Jan;119(1):182-91.

Jarrett et al. Impact of recess on classroom behavior: group effects and individual differences. J Educ Res. 1998;92(2): 121–126.

Stellino et al. Intrinsically motivated, free-time physical activity: considerations for recess. J Phys Educ, Recreat Dance. 2008;79(4):37–40.

Reclaiming Skepticism

The other day, while poking around on the Interwebs, I ran across a quote that I’ve seen more than once, never attributed, along the lines of:

To the believer, no proof is required; to the skeptic, no proof is sufficient.

Though this statement is partially accurate — a person who believes in God, for instance, does so on faith and neither requires nor looks for evidence to justify those beliefs — its inaccuracies distress me. The term skeptic seems to have come to mean, at least in common usage, a person who does not believe in {xyz}, even when presented with evidence. For instance, those individuals (mostly Americans) who continue to doggedly refuse to acknowledge the reality of global warming, despite overwhelming evidence to the contrary, are often called (and call themselves) climate skeptics. I take issue with this. A skeptic is a person who insists upon seeing and evaluating the evidence before passing judgment. A skeptic appropriately reassesses his or her beliefs when presented with new evidence. A skeptic is a critical thinker, and is not emotionally attached to the outcome of his or her thinking process. A person who found the hypothesis of global warming interesting — but not necessarily convincing — back in the late 1970s when the National Academy of Sciences released the first major report on climate change would have been appropriate called a skeptic. A person who refuses to believe in global warming today — when every major government on Earth except that of the U.S. openly acknowledges the problem, when empirical evidence drawn from weather patterns, animal behavior patterns, and atmospheric data all support significant warming patterns — is not a skeptic, but a denier.

In my attempt to find an original source for the believer/skeptic quote, I ran across the following on a web forum for discussion of paranormal phenomena; I thought it was absolutely fabulously stated:

To the skeptic, evidence is everything. To the believer, everything is evidence.

-A forum user who calls himself TheBoyPaj on JREF

As there appears to be no other reference on Google to this particular quote, I believe it’s an original. As such, to TheBoyPaj — wherever and whomever you are — thank you. I’d like to shake your hand.

“To the skeptic, evidence is everything,” he says. No doubt. In this age of the University of Google, though, examining evidence is less a matter of finding information than it is of evaluating that information for its quality. Take, for instance, the growing concern in some circles that vaccines are linked to autism. I had one of my university classes read Seth Mnookin’s wonderful book The Panic Virus recently; in it, Mnookin explains that the “evidence” used to support this conviction ranges from the wildly inaccurate to the irrelevant. An example of the former is the poorly conducted, fraudulent study published in The Lancet by Andrew Wakefield et al. An example of the latter is toxicological data on methyl mercury (the kind in seafood), which is a potent neurotoxin in very small doses. Anti-vaccine advocates refer to such data in support of their objection to the presence and quantity of mercury in vaccines. However such references are almost always made without specification of the particular form of mercury present; thimerosal, used as a vaccine preservative, contains not methyl but ethyl mercury. This distinction seems small (after all, mercury is mercury, right?), but is, in fact, critical. Methyl mercury and ethyl mercury are as different as methyl alcohol and ethyl alcohol: the former is lethal even in small doses, while the latter is the alcohol in beer, wine, and liquor; while toxic in large doses, it’s safe and pleasurable in appropriate quantities. Maybe the most descriptive and accurate phrasing would be, “To the skeptic, the quantity and quality of evidence is everything,” but then, that wouldn’t sound nearly as graceful.

On the flip side, there’s the matter of blind belief. The Panic Virus is excellently researched and beautifully written, and I won’t do it the disservice of trying to summarize it here. To the point, though, Mnookin interviews a number of higher-ups in autism societies who firmly believe in the thoroughly-debunked vaccine-autism link and who tell him (in paraphrased terms) that it doesn’t matter what the science shows; we will continue to believe — we know in our hearts — that vaccines cause autism. “To the believer, everything is evidence,” TheBoyPaj says, and he’s absolutely right.



Wakefield et al. Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet. 1998 Feb 28;351:637-41. RETRACTED (see Lancet. 2010 Feb 6;375:445)

“Baby Unplugged”/Blue Manatee Press Review

I generally try to keep evidence-based information on one “side” of the SquintMom site, and bloggier things on the other side. A book review would typically go on the blog side, but in this particular case, the concept behind Baby Unplugged and Blue Manatee Press is so well supported by scientific evidence that it’s going on the evidence-based parenting side.

The Baby Unplugged concept was developed by Dr. John Hutton, a pediatrician whose stated mission is “Uniting science and sense to be screen-free until age 3.” In addition to his blog, Dr. Hutton writes books and owns Blue Manatee Press, which publishes both his books and those of selected authors whose work espouses the same principles. The Blue Manatee Boxes storefront sells books from Blue Manatee Press and other publishers; the distinguishing feature of the business is that the books come packaged in an awesome, low-tech, plain ol’ cardboard box filled with biodegradable packing noodles, a sponge, a green crayon, an instructional insert that encourages creative play and environmentally sound behavior, and (of course) the books. As far as the packing noodles go, they’re pretty fabulous for two reasons. First, they’re much “greener” than styrofoam. Additionally, though, kids can use them to play. They break down when exposed to lots of water, but just a little bit of water — applied with the conveniently included sponge — makes them perfectly sticky, explains the instructional insert:

As for the green crayon, the box insert suggests using it to color the box like a turtle shell for playing dress-up. Of course, there are lots of ways to use a box and some packing noodles, and the idea behind the insert is to provide inspiration for kids and parents who need a little help getting their imaginations fired up.

Once everyone’s done playing with the box, it makes a great biodegradable planter, explains the box insert. I love this idea; W’s really into garden stuff, and I’m planning to let her plant flowers in the box, watch them grow inside for a while (where they’ll be sheltered from the still-blazing-hot sun), then plant them — box and all — in the garden, where the box will break down.

As much as W and I love the Blue Manatee Box and its packing noodle contents, we love the books that were inside even more. We got three of Dr. Hutton’s books (Ball, Pets, and Yard), and one book by Sandra Gross and Leah Busch called Toast To Counting, also published by Blue Manatee Press. Hutton’s books feature simple language and illustrations, and all share the same basic message: playing and being creative (and active) is way, WAY cool. From Pets:

Robot dogs are cool and all, but they’ve got nothing on a real puppy, hamster, or fish.

W enjoys all three of Dr. Hutton’s books, but Pets is definitely her favorite. We got two cats (the first pets we’ve ever owned) about three weeks ago, and she’s absolutely in love with them. She gets a kick out of reading about other kids and their pets.

Toast to Counting is a little different; there are no words at all until the last page of the book. Instead, the pictures speak for themselves (and parents can make up their own words, which makes the book ultra-interactive). In the book, a piece of bread becomes a cute little face with egg eyes, a butter nose, and so forth, where each piece of the face added to the toast introduces a number (1 piece of toast, 2 eggs, etc):

I just love the little toast guy!

As an awesome bonus, the images in Toast To Counting are all made of glass; the authors, in addition to being teachers, are glass artists. Neat!

Both W and I are now committed fans of Blue Manatee Boxes/Press and Baby Unplugged for their pro-environment business practices and their fun-to-read books that encourage open-ended play. The back cover of each of Dr. Hutton’s books sums up the message of Baby Unplugged nicely:

I think a Blue Manatee box is going to be my new go-to birthday gift for toddlers!

For the purposes of writing this review, I was given four books from Blue Manatee Press. All opinions are my own.

Defiance and Inattention Increase Likelihood of Smoking, Drug Use

I received the following research story via email, and found it fascinating. This was written by Marise Daigle of the Sainte-Justine Mother and Child University Hospital Centre in Montreal. I have added emphasis (bold type) to highlight particularly salient points.


MONTREAL, Canada, August 1, 2012 – Children who exhibit oppositional behavior run the risk of becoming addicted to nicotine, cannabis and cocaine whilst Inattention symptoms represent a specific additional risk of nicotine addiction. Nevertheless, hyperactivity in itself does not seem to be associated with any specific risk of substance abuse or dependence. This is what researchers at the Sainte-Justine University Hospital Center’s (UHC) Research Center and the University of Montreal concluded following a 15-year population-based study published in Molecular Psychiatry.

In order to delineate the roles played by inattention, hyperactivity, opposition, anxiety and adversity, the behavior of 1,803 children between 6 and 12 years of age were evaluated annually by their mothers and teachers. Over half the participants were females. The study revealed that by the age of 21, 13.4% were either abusing or addicted to alcohol, 9.1% to cannabis, and 2.0% to cocaine. Tobacco addiction was a problem for 30.7 % of the participants.

The link between attention deficit hyperactivity disorder (ADHD) in childhood and substance abuse in adulthood was already known. However, very few studies have been undertaken into the particular and respective roles of behavioural symptoms such as opposition that are often concomitant with ADHD (without being part of the disorder), attention deficit and hyperactivity. Furthermore, at least as many girls as boys were sampled in order to assess the potential impact of gender on the findings.

“By taking into account the unique effect of inattention and hyperactivity, which had seldom been considered separately before, we came to realize that the link between ADHD symptoms in childhood and substance abuse in adulthood was overestimated and hyperactivity in itself did not seem, in this study, to predispose for future substance abuse,” observed Dr. Jean-Baptiste Pingault, a postdoctoral fellow and first author of the study conducted under the supervision of Drs Sylvana Côté  and Richard E. Tremblay, both researchers at the Sainte-Justine UHC’s Research Center and professors at the University of Montreal.

“We have rather observed strong oppositional behaviors to be associated with cannabis and cocaine abuse. In ADHD symptoms, only inattention is closely correlated with nicotine addiction,” he continued. As for the impact of gender on findings, the study reveals opposition and inattention play a largely identical role in girls and boys. However, within the context of the study, it was established that boys consumed more cannabis and alcohol, while girls smoked more cigarettes.

Opposition and Drug Addiction
The strongest behavioral predictor of substance abuse lies in frequent oppositional behavior in childhood, which can be recognized through traits such as irritability, being quick to “fly off the handle,” disobedience, refusal to share materials with others to carry out a task, blaming others and being inconsiderate of others
. In fact, in strongly oppositional children, the risk of tobacco abuse, once other factors were taken into account, was 1.4 times higher than in children who exhibited little oppositional behavior. The risk is 2.1 times higher for cannabis abuse and 2.9 times higher for cocaine abuse. It should be noted that the mothers’ evaluations provided further essential information in relation to the teachers’ evaluations. In fact, some children who were declared highly oppositional by their mothers, but not at all by their teachers, also ran a higher risk of substance abuse and addiction.

Inattention and Smoking
The other important correlation established by the study was the link between inattention and smoking. Very inattentive children had a 1.7-fold increased risk of becoming addicted to tobacco. The degree of inattention even reveals the intensity of future nicotine addiction. The link supported the hypothesis that inattentive people would use tobacco as a “treatment” to help them concentrate.

“If other studies can establish a chemical relation of cause and effect between ADHD symptoms and smoking, we could suppose that treating inattention symptoms would make it easier to quit smoking. Until this is demonstrated, our study’s findings nonetheless suggest that the prevention or treatment of inattention and opposition symptoms in children could reduce the risk of smoking and drug abuse in adulthood,” concluded Dr. Pingault.

About the CHU Sainte-Justine Research Center
The Sainte-Justine University Hospital Research Center is a leading mother-child research institution affiliated with the University of Montreal, officially known as Université de Montréal. It brings together more than 1200 people, including over 200 researchers and 450 graduate and post-graduate students who carry out fundamental, clinical, translational, and evaluative research on mother and child health. Research work falls under six research axes, namely Health Outcomes; Brain Diseases; Musculoskeletal Diseases and Movement Sciences; Viral and Immune Disorders and Cancers; Fetomaternal and Neonatal Pathologies; and Metabolic Health. It is focused on finding innovative prevention means, faster and less invasive treatments, as well as personalized approaches to medicine. The Center is part of the Sainte-Justine University Hospital Centre, which is the largest mother-child centre in Canada and second most important in North America. More on


This story was originally published here, on the website of the Sainte-Justine CHU. Reprinted with permission.

Spanking Associated With Development Of Mental Disorders, New Study Suggests

The American Academy of Pediatrics (AAP) is a relatively conservative organization, in the sense that they require a significant body of evidence before making a statement or changing a recommendation. For instance, they equivocate on infant circumcision, ignoring both the violent protestations of those who feel the practice is immoral as well as the body of evidence that suggests it’s of modest health benefit (see this post and this one for more discussion on this topic). One topic on which the AAP does take a firm stance, however, is that of corporal punishment and spanking. From the Healthy Children website (AAP):

The American Academy of Pediatrics does not recommend spanking. Although most Americans were spanked as children, we now know that it has several important side effects.

  • Even though spanking may seem to “work” at first, it loses its impact after a while.
  • Because most parents do not want to spank, they are less likely to be consistent.
  • Spanking increases aggression and anger instead of teaching responsibility.
  • Parents may intend to stay calm but often do not, and then regret their actions later.
  • Spanking can lead to physical struggles and even grow to the point of harming the child.

It is true that many adults who were spanked as children may be well-adjusted and caring people today. However, research has shown that, when compared with children who are not spanked, children who are spanked are more likely to become adults who are depressed, use alcohol, have more anger, hit their own children, hit their spouses, and engage in crime and violence. These adult outcomes make sense because spanking teaches a child that causing others pain is OK if you’re frustrated or want to maintain control—even with those you love. A child is not likely to see the difference between getting spanked from his parents and hitting a sibling or another child when he doesn’t get what he wants.

Each of the statements made above is backed by solid scientific evidence (see, for instance, Bender et al, Berlin et al, Bradley et al, Gershoff, E., Knox, M., Slade et al, Strassburg et al, Strauss et al, Taylor et al).

It’s known that physical and emotional abuse and neglect are associated with certain mental disorders, including major depression and other mood disorders, schizophrenia, obsessive compulsive disorder, and the like (see, for instance, Fergusson et al, Kessler et al, MacMillan et al, Scott et al). One question that has remained unanswered, however, is whether children who are spanked are more likely to experience these same types of mental disorders during adulthood than those who are not spanked.

A new study examined the relationship between spanking (and similar punishments, all in the absence of more serious abuse or neglect) and mental disorders in an attempt to answer this question (Afifi et al). The study involved an examination of a large quantity of data that included information on more than 34,000 individuals. Participants who reported having been spanked, slapped, or similar were compared to those who reported not having been physically punished. Individuals who were spanked but who also reported having been physically, sexually, or emotionally abused or neglected were discarded from the data set, leaving a total of about 20,500 individuals whose data were analyzed.

Of these, just over 19,000 reported not experiencing physical punishment, while 1258 did experience such punishments. Once the data were corrected to remove possible confounding variables (such as parents with mental disorders, which would predispose children to mental disorders), the prevalence of mental disorders was approximately 2-7% higher among adults who’d been spanked as children as compared to those who had not.

Unfortunately, while I’m intellectually inclined to believe that there may be an association between physical punishment during childhood and adult mental disorder, I have a number of concerns about this study and its methodology. First, it’s notable that of over 34,000 original records, only 20,500 remained once the authors removed individuals who had been physically, sexually, or emotionally abused or neglected. This is a tremendous portion of the original population, and simply doesn’t make intuitive sense. On further examination, I find two potential explanations. First, the data were pulled from the National Epidemiologic Survey on Alcohol and Related Conditions, which despite the implications of its name, surveyed a large group of individuals who were more-or-less representative of the general population for information about substance use/abuse habits and mental disorders (Grant et al). Grant does note that the survey over-sampled certain minority demographics, and further, the survey was voluntary and depended upon self-report of information (with an approximate return rate of 81%). As such, it’s possible that individuals who were resentful of the way they’d been parented (and who were perhaps more likely to report a mental disorder) were also more likely to return the survey. Unfortunately, there’s no way to know whether this is a significant factor.

Far more likely to produce the startling proportion of survey respondents who were not included in this study because of abuse and/or neglect is the definition of abuse used by Afifi et al. Per the authors, individuals who were removed from the study population were those who (among more traditional definitions) were hit hard enough to leave marks, had objects thrown at them, were sworn at, and/or were made afraid during or by punishments. It’s not difficult to imagine, given this definition, that there would be very few individuals left in the physical punishment category once those in the abuse category had been removed.* Whether the authors’ definition of abuse is appropriate or not, the exclusion from the study of many individuals who were physically punished in ways that would not be considered abuse in the traditional sense weakens the study by reducing the number and the type of participants. It would be interesting to see what the data would reveal if the definition of abuse were more narrow (and more traditional), allowing inclusion of a larger group of those who’d been physically punished in “non-abusive” ways.

*Note that here I do not express either agreement or disagreement with the authors’ definition of abuse; I merely suggest that per the given definition, it’s not surprising that there were relatively few participants left in the punishment condition.

Along these same lines, the authors apparently fail to recognize the effect that the elimination of this large group of participants might have had on their data, leading them to make some bizarre observations. For instance, they note that physical punishment is more likely in families in which parents are better educated (39.2% of physically-punished children had a parent with a post-secondary degree) than in less-educated families (8.8% of physically-punished children had parents who hadn’t completed high school). The authors expressed surprise at this finding, as would I were I faced with the raw data. However, a more reasonable explanation (and of course, without the 14,000 records that were not included in the study, this is purely speculative) is that individuals from lower-education families were more likely to be punished physically in a way the authors deemed abusive, and were thus thrown out of the study. From a scientific perspective, the lack of awareness of these sorts of possibilities on the part of the authors distresses me; generally speaking, scientists value the work of other scientists more highly when the researchers are aware of potential confounding factors and methodological limitations.

Another concern I have with the study is that the authors make the mistake of confusing (at least in their language) correlation with causation. In the abstract results, they state:

Approximately 2% to 5% of [one category of mental] disorders and 4% to 7% of [another category of mental] disorders were attributable to harsh physical punishment.

Based upon the study design, it’s impossible to say that the disorders were attributable to harsh punishment; the design allows only the statement that harsh punishments were positively correlated with mental disorders. Regardless of this error, however, the findings nevertheless somewhat strengthen the (already considerable) body of evidence suggesting that spanking and other corporal punishments aren’t effective, and are likely harmful.

As a scientist, I’m not particularly impressed by this new research; I’d want to see what sort of data the very large group of survey respondents (about 14,000 in all) who were thrown out for abuse might have contributed if the definition of abuse had been a bit more in keeping with traditional usage. Again, I want to make it clear that just because a punishment isn’t classically defined as “abuse” doesn’t make it right. In classical terms, however (and here I refer, for instance, to the social mores regarding appropriate discipline techniques in the 50s, 60s, 70s, and 80s) “spanking” was one thing, and “abuse” was another. Clearly, the delineation between the two isn’t absolute, but I nevertheless feel that by defining “abuse” too broadly, we lose the opportunity to extract potentially valuable information about the damage done by “non-abusive” physical punishment.

The weaknesses of this particular study aside, there is nevertheless a tremendous body of compelling science that shows spanking and other physical punishments are simply not effective, and likely contribute to at least some lasting negative effects through childhood and into adulthood. In lieu of spanking and corporal punishment, the AAP recommends techniques such as natural consequences and time-out. For those who don’t mind a slightly more technical read, there’s an interesting paper by the AAP’s Committee on Psychosocial Aspects of Child and Family Health here. Those looking for a less technical guide to effective and positive discipline may find some good information in Elizabeth Pantley’s The No-Cry Discipline Solution (McGraw-Hill), which has suggestions for children of all ages, and Harvey Karp’s The Happiest Toddler On The Block (Bantam), which focuses on children aged 12 months to 4 years.

Science Bottom Line:* The new study of physical punishment and mental disorders in adults doesn’t establish a strong link due to flawed methodology and interpretation, but the existing body of research that discredits spanking as a viable discipline technique is large enough to be compelling without the addition of these results.


How do you feel about spanking children?



Afifi et al. Physical Punishment and Mental Disorders: Results From a Nationally Representative US Sample. Pediatrics. 2012 Jul 2. [Epub ahead of print]

Bender et al. Use of harsh physical discipline and developmental outcomes in adolescence. Dev Psychopathol. 2007;19(1):227–242

Berlin et al. Correlates and consequences of spanking and verbal punishment for low-income white, African American, and Mexican American toddlers. Child Dev. 2009;80(5):1403–1420

Bradley et al. The home environments of chil- dren in the United States part II: relations with behavioral development through age thirteen. Child Dev. 2001;72(6):1868–1886

Fergusson et al. Exposure to childhood sexual and physical abuse and adjustment in early adulthood. Child Abuse Negl. 2008;32(6):607–619

Gershoff, E. Corporal punishment by par- ents and associated child behaviors and experiences: a meta-analytic and theoret- ical review. Psychol Bull. 2002;128(4):539–579

Grant et al. Prevalence, correlates, co-morbidity, and comparative disability of DSM-IV generalized anxiety disorder in the USA: results from the National Epidemiologic Survey on Alcohol and Related Conditions. Psychol Med. 2005;35(12):1747–1759

Kessler et al. Childhood adversity and adult psychiatric disorder in the US National Comorbidity Survey. Psychol Med. 1997;27(5):1101–1119

Knox, M. On hitting children: a review of corporal punishment in the United States. J Pediatr Health Care. 2010;24(2):103–107

MacMillan et al. Childhood abuse and lifetime psychopathology in a community sample. Am J Psy- chiatry. 2001;158(11):1878–1883

Scott et al. Prospectively ascertained child maltreatment and its association with DSM-IV mental disorders in young adults. Arch Gen Psychiatry. 2010; 67(7):712–719

Slade et al. Spanking in early childhood and later behavior problems: a prospective study of infants and young toddlers. Pediatrics. 2004;113(5):1321–1330

Strassburg et al. Spanking in the home and children’s sub- sequent aggression toward kindergarten peers. Dev Psychopathol. 1994;6(3):445–461

Strauss et al. Spanking by parents and subsequent anti- social behavior of children. Arch Pediatr Adolesc Med. 1997;151(8):761–767

Taylor et al. Mothers’ spanking of 3-year-old children and subsequent risk of children’s aggressive behavior. Pediatrics. 2010;125(5)

Chemicals and Toxins — What Is Safe?

One of the most common questions I get from SquintMom readers is along the lines of is item/substance/compound XYZ toxic? I’d like to go ahead and answer this once and for all: YES, it is.

Now let me explain what I mean, and how I can answer this very generic question in a catch-all way without specifying the item/substance/compound to which I refer. Because he said it so well that it doesn’t need rephrasing, I’ll quote the Renaissance-era botanist Philippus Aureolus Paracelsus, who said:

All substances are poisons; there is none that is not a poison. The right dose differentiates a poison from a remedy.

Phrased more generally, this is simply that any substance can be either safe or toxic; the dose (quantity) to which one is exposed is what makes the difference. I’ve mentioned in previous posts (like this one about oxybenzone in sunscreen) that the notoriously jumpy Environmental Working Group (EWG) systematically fails to recognize this particular principle; they have a tendency to vilify anything that proves toxic in any dose, under any conditions. This attitude, however well intentioned, leads us to some interesting places. Pause for a moment and check out the cautionary website DHMO.org. Note that the highly toxic dihydrogen monoxide (DHMO) is associated with cancer (it’s found in every tumor ever identified), has serious environmental impact (it’s a major greenhouse gas and overexposure is associated with thousands upon thousands of deaths every year), and, per the website:

[DHMO’s] basis is the highly reactive hydroxyl radical, a species shown to mutate DNA, denature proteins, disrupt cell membranes, and chemically alter critical neurotransmitters.

Sounds horrid, doesn’t it? No doubt we should ban it. Except that…DHMO.org is a joke website, and dihydrogen monoxide is the almost never-used, formal chemical name for water.

None of the information on DHMO.org is false, which is what makes it both amusing and apropos to this discussion. Water does, in fact, directly result in many deaths. Not only through “overexposure” via flooding and/or drowning, but also through overconsumption. For instance, in 2007, a radio station held a contest (“Hold your wee for a Wii”), the idea of which was to drink as much water as possible without a bathroom break; the caller who drank the most would win a coveted Wii game console. Contestant Jennifer Strange won (and then lost) by consuming more than 2 gallons of water in the space of less than an hour. She died shortly thereafter of hyponatremia, a condition in which there is an insufficient concentration of sodium in the body fluids to support life (sodium is critical to cellular function, neural conduction, muscular contraction, brain function, and so forth). This is not the only incident of water toxicity on record; similar cases have resulted from fraternity hazings, bizarre diet plans, and overconsumption of water during endurance sporting events like marathons.

On the other hand, there are substances that we typically consider highly toxic that are, in the right dose, of great medicinal utility. Clostridium botulinum is a species of bacteria that produces botulinum toxin, generally considered the deadliest substance on Earth. The average 150 pound man would have a 50:50 chance of survival if exposed to merely 341 ng (that’s less than a millionth of a gram) of pure botulinum toxin. Regardless, marketed under the trade name Botox, botulinum toxin is used for cosmetic purposes (wrinkle treatment and prevention). Of perhaps greater medical importance, it’s also used to ease the painful symptoms of temporomandibular joint syndrome (TMJ) and other spasmodic disorders, and mitigate the symptoms of diabetic neuropathy (damage to peripheral nerves, often in the feet, due to diabetes).

Further complicating matters, our perception that “natural” substances are somehow safer or better for us than “artificial” substances is misinformed. A simple example is the flavoring agents found in many foods. While the common perception is that natural flavors come from the food of which they taste (strawberry flavor, for instance, comes from strawberries), nothing could be further from the truth. In reality, natural and artificial flavors are generally identical chemicals, collected or produced in different ways.* Natural almond flavor, for instance, isn’t a mixture of “natural substances” that come from almonds. Instead, it’s a chemical called benzaldehyde that is extracted from peach pits. Artificial almond flavor is also benzaldehyde, but unlike natural almond flavor, the artificial stuff is made in the lab. Funnily enough, it’s possible to get benzaldehyde made in the lab much more pure than that extracted from peach pits. Further, the stuff that comes from peach pits — the natural almond flavor, remember — contains small amounts of deadly cyanide that occurs naturally in those same peach pits (one of many reasons it’s not wise to eat the pits of stone fruit).

*Eric Schlosser’s excellent book Fast Food Nation contains a very interesting chapter on this topic, for further reading.

Where does this leave us, in trying to avoid toxins? First, as a chemist, let me just say that the word toxin is very often misused in popular sources and conversation, and the word chemical is almost always misused. “Chemicals” are not bad things that cause harm and should be avoided. Instead, they are matter; they are what makes up the physical universe. Nothing that has mass and occupies space — nothing we touch, eat, drink, breathe — is not chemical. There’s no such thing as chemical-free bread, shampoo, or paint. Water is a chemical (and — let’s not forget — a toxic one at that). With regard to toxins, the word is used too often in a vague, handwaving sense on the Interwebs. I see pop-authors (who are generally trying to sell something) write about how Product X contains “toxins,” and should therefore be avoided, or Product Y (which they’re selling) contains no toxins.* I’m not sure what these folks mean when they say “toxins” (and since they rarely name said toxins, I’m not sure they know either); after all, let’s not forget that all substances are toxic in the right dose.

*Or worse yet, Product Y (which they’re selling) is a detoxifying agent. This is ridiculous; almost all humans (with the exception of a few with significant disease) are possessed of one of the most powerful detoxifying mechanisms known to man — a liver. Livers work really well, particularly when they’re left alone to do their job.

This is not to say that we should all go about our business with no concern whatsoever for the things we touch/eat/drink/breathe; it’s simply to say that we simultaneously worry too much and worry too little about “chemicals.” To take one particular example, a few scare-articles about bisphenol A (BPA) have some of us so worried (and confused) that we’re willing to shell out extra cash for BPA-free diaper wipe containers, toys, and even a bath toy organizer. In reality, if BPA has any effect at all in doses to which we’re routinely exposed (which has not yet been established), it would require significant physical contact with the compound to absorb it. Holding, playing with, or storing one’s bath toys in a BPA-containing item would not be a problem, particularly given that while the absorption rate of BPA through human skin hasn’t been thoroughly evaluated or established, it nevertheless appears to be significantly lower than the (already modest) rate of absorption through the skin of other animals (Marquet et al). Based upon the current research, might it be worth avoiding storing food in BPA-containing plastics? Possibly. This is because food might leech BPA out of the plastic in sufficient quantities to possibly have some effect on people (because we eat the food, which gives it an easy route into the system). Is it worth it to avoid all BPA in our houses, however? Simply, no. And on that note, it particularly amuses me to watch women with painted nails shopping for BPA-free toys for their daughters (also with painted nails), given that the exposure to potentially harmful substances (like toluene) is much greater when one physically paints said chemicals on one’s body.*

*For those who are curious, I do paint my nails, because I really don’t think this is that big a deal. But it’s certainly a more significant exposure to chemicals (ew! chemicals!) than touching a rubber ducky in the tub.

So, we worry too much. But we also worry too little. In our desire for the “natural” (whatever that means), we choose the cyanide-laced flavoring agent over the one made under strict conditions and control in the lab. We go to the natural foods store and buy herbs to treat our ailments — which are essentially unregulated for either safety or efficacy, and which may interact unsafely with prescription and over-the-counter drugs or be toxic in their own right — rather than using the “unnatural chemicals” prescribed by medical professionals, despite the fact that the latter have undergone many years of pre-marketing research, followed by decades of post-marketing surveillance. We’re more willing to expose our children to the 1/330 risk of death due to the measles than the 1/3000 risk of a moderate side effect of measles vaccination (e.g. seizure with no permanent effects, mild rash), and immeasurably small risk of serious side effect. We further eschew the vaccination because, in a complete failure to understand the mechanics of human immunity, we have come to believe that “natural” immunity from disease is superior to “artificial” immunity from vaccination. When it comes to the “natural” versus the “toxic” and/or “chemical,” we’re chasing flies out of the chicken coop while the foxes sneak in.

So what do we do about it? This is difficult. We know that all substances are toxic in the right (wrong?) dose, but when it comes to many substances, we still don’t know what that dose is. Some exposures are unavoidable (by virtue of living in a city, for instance, one is going to be exposed to a certain amount of benzene from exhaust, industrial processes, etc). Some exposures are avoidable, but avoiding them reduces quality of life (no one HAS to eat foods containing coloring agents, for instance, many of which are of questionable safety, but the complete avoidance of these would make for a stoic existence, particularly for children). In most cases, when it comes to toxic chemicals (and once more, all substances are chemicals, and all chemicals are toxic when one is exposed to them…all together now…in the right dose), one must do a risk-to-benefit analysis. Some cases are relatively clear. Is codeine toxic? Yes, in the right dose. Is it worth the risk to take codeine for recreational purposes? Probably not. Is it worth the risk to take codeine after a painful surgery? Probably. Is water toxic? Yes, in the right dose. Is it worth the risk to drink water when one is thirsty? Absolutely. Is it worth the risk to drink water to win a contest? Probably not. Some cases are less so, as with the previous example of BPA. With the evidence still equivocal, financial means and convenience likely become a large part of the decision. Those of greater means or with greater willingness to be inconvenienced might buy the BPA-free rubbery ducky, the BPA-free cabinet safety locks. Others might decide to buy the BPA-free food storage, but be content with the plain old, BPA-containing bath caddy. Regardless of these personal decisions when it comes to substances of yet-unknown safety, it’s worth remembering that the media, the product manufacturers, and the fad-authors capitalize upon the lucrative combination of public confusion and fear, and that the words “chemical,” “toxic,” “artificial,” and “natural” are as powerful as they are misused and misunderstood.


Marquet et al. In vivo and ex vivo percutaneous absorption of [14C]-bisphenol A in rats: a possible extrapolation to human absorption? Arch Toxicol. 2011 Sep;85(9):1035-43. Epub 2011 Feb 2.

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