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What Is Thimerosal and Why Are Some People Worried About it?

By April 14, 2016 3 Comments

“I don’t wanna put mercury in my baby, Doc; it’s poison.”  After Robert DeNiro’s anti-vaccination massive misstep Tuesday, I’m yet again, dreading hearing these words.

This is where, as a pediatrician, I grit my teeth (sorry, dentists).  I know that when I parent tells me this,  that science has lost another battle with fear in the race to inform families first. Since the race has been lost, I know I’m going to have to work from behind to get this child protected from deadly diseases.

There will likely be a lot of questions for me.  Questions based on faulty premises and that question my integrity as a doctor, as a dad and as a person.  I will put my pride aside and try to help these parents make the right choice for their kid.

I will explain that thimerosal is not mercury (although it contains very small amounts of it).

I will explain that even though there was no evidence that thimerosal was harmful, that it was removed from early childhood vaccines in 2001.

I will try to communicate with evidence-based information.

I will bring up the fact that Andy Wakefield, the man behind the current anti-vaccine movement and the movement has had his medical license revoked after the General Medical Council in the UK found he committed professional misconduct and acted dishonestly and irresponsibly. I will remind them that they don’t know many people that sleep in iron lungs because of Salk’s polio vaccine.

Reluctantly, I may even have to go into my personal life and divulge that my entire household (my wife, two girls and I) is fully vaccinated. These things may or may not sway the family.The conversation may end in an awkward stalemate. There could be a conversion that occurs over months.

I hope not, though, “because deadly diseases ain’t waitin’ on you to decide.” I get colloquial once we’re all good friends.

Sometimes people change their hearts and minds right away when I reassure them; those conversations are more fun, but I am usually wary of the spurious information that is just outside the hospital doors, or sometimes in the room with me on their smart phones.  I know once I’m done talking to them, there’s a whole lot of noise outside waiting to undo what I just did.

Robert DeNiro Appeared on NBC's Today Show on Tuesday

Robert De Niro Appeared on NBC’s Today Show on Tuesday

Like Tuesday, during The Interview Heard Around the Internet, when one of the greatest (the greatest?) screen actors of all time went full anti-science on the Today Show. Robert DeNiro, in explaining why he regrets the pulling of the movie “Vaxxed: from cover-up to catastrophe” from his Tribeca Film Festival, made some dangerously inaccurate statements about vaccines and autism.

In case you missed the discussions from a few weeks ago, here’s the skinny: Big-time festival announces the screening of a pro-disease (or, anti-vaccination) motion picture, the scientific community loses our collective mind and lets them know it’s a dangerous choice, Big-time festival pulls the movie, anti-vaxxers go up in arms. The science community was FINE with this result (you know, the support of actual scientific fact), even tentatively giddy.

Bobby D pulled no punches in his NBC interview, citing most of the tried-and-true tropes of the antivax movement: he stated that vaccine science is not “settled,” claimed “overnight” changes in children after immunizations, talked about mercury in vaccines and even gave the ol’ “I’m not anti-vaccine” speech, which is pretty much only said by people that are.

I’d love to make a reference to the classic “Just when I thought I was out, they pull me back in”… but that was Pacino’s line.

As a parent, if someone told you the nonsense that De Niro spouted on the Today Show, it would sound terrifying. No one wants to cause harm to their own child (or someone else’s). As a doctor I can tell you I’ve dedicated my life to helping parents keep their kids safe.  I don’t want to see your kid hurt either.  So let me break down De Niro’s claims starting with thimerosal.

The reality is that if De Niro got his information from better sources and actually talked to real scientists he’d know that a lot of what he just said isn’t true. He’d know that thimerosal hasn’t been in early childhood vaccines for 15 years, and he’d know that it was never in the MMR vaccine, the one that his boy Andy Wakefield falsely claims causes autism.

He’d also know that thimerosal is a mercury-based substance used in multi-dose vials of vaccines as preservative. It kills bacteria and prevents the growth of fungus in the vial, to help keep it sterile and safe for injection. It’s also a substance found in tattoo ink in concentrations thousands of times higher than what is found in vaccines. The compound breaks down into ethylmercury, half of which is broken down and rendered “ineffective” by the body in about a week. Then, we poop it out!

He’d know that in term of quantities, the amount of mercury given in a yearly flu vaccine is 25 micrograms (mu). The amount needed to kill 50% of living organisms (LD50) is 98 milligrams (mg) per kilogram (kg) of body weight. Remember, 1 milligram is equivalent to 1,000 micograms – so this means that, for a 10 kilogram (about 22 pound) child to have life-threatening effects, the child would need to have 980,000 micrograms of mercury. At one time.

He’d contrast this with methylmercury, which is found in tuna and industrial waste or elemental mercury which used to be found in old school thermometers (You may have even played with spheres of it as a kid if you’re an old fogey, like me). These are the types of mercury that we really worry about.  With methylmercury there are so many ways we are exposed and with elemental mercury we’re usually exposed to a lot when we’re exposed (like playing with broken thermometers).

Methylmercury is the one that makes us warn pregnant women about salmon intake.  Elemental mercury is the kind was used when making felt hats, giving the makers neurological damage centuries ago, i.e. The Mad Hatter. It takes about six weeks for the body to break this substance down to its ineffective state. In the meantime, the compound binds strongly to fat and neurological tissue; it finds its way to the brain, where it causes intellectual deficits.

This is why it’s important for people like De Niro to know the difference between mercury compounds, but he didn’t (or he doesn’t).

How did we get to this point? Why are parents distrusting of the scientists and physicians they chose, and continue to choose to listen to celebrities and snake oil salesmen?  Why are we still discussing something that’s not even in early childhood vaccines any more?  Why are we talking about “mercury” that was never even in the MMR vaccine to begin with?

I believe that three, nearly concurrent events happened almost twenty years ago that set this phenomenon in motion:

1) The FDA Modernization Act of 1997 required vaccine manufacturers to give detailed information to the government about all mercury-containing products. At the time, jabs for Hepatitis B, DTaP (diphtheria, tetanus and pertussis) and inactivated Polio had trace to small amounts of thimerosal (a mercury-based preservative) in their ingredients.

2) In 1998, Andrew Wakefield, a UK gastroenterologist published his infamous study in the Lancet that claimed a link between the MMR vaccine and autism (that’s since been retracted – more on that in a moment).

3) After vaccination rates declined because parents were so concerned about Wakefield’s study and lots of talk about thimerosal the CDC recommended the FDA order thimerosal removed from early childhood vaccines (except for the flu shot).  We’re still talking about this 15 years later, so pulling thimerosal from the vaccines didn’t work.

After the FDA Modernization Act, and widespread fears about autism following the paper published by Wakefield, there was quite a bit of public outcry for changes to be made in vaccines. In spite of good scientific evidence that there was no link between thimerosal and autism, government agencies and vaccine manufacturers decided to make all childhood vaccines thimerosal free. This decision placated some, but many pediatricians feel that it served as a capitulation to non-science. Thimerosal, at this point, only exists for children in certain flu vaccines. There is no thimerosal in the dose for children from 0 to 3 years-old.

In terms of Wakefield’s claim, his paper stating that a combined MMR vaccine was linked to autism was retracted in 2010 and his license to practice medicine was stripped in the same year. In the eyes of many health professionals, however, the damage had already been done. Vaccine rates dropped in several Western nations in the early 2000s, leading to multiple outbreaks of diseases that had been on a steady decline or even eradicated from some countries.

In spite of the overwhelming, worldwide, scientific evidence that vaccinations are safe and effective, claims of “toxins” and “poisonings” continue on the internet and at family gatherings. I won’t link to them here, but trust me. My job, as I see it, is to continue to fight the good fight against vaccine misinformation. The more people understand what we are giving their children, the more vaccine uptake and suffering prevented.

Yet we still have neighbors, family members, and very high-profile celebrities who are against or that “question” the safety of vaccinations. You know the ones: they show up on your Facebook timeline once a week with a story about “the medical industrial complex” or tell you that Big Pharma is out to make money by “making our kids zombies.” These folk often have a dubious story to share about a medical catastrophe or grand claims about medical marijuana curing cancer along the lines of “it also raised my cousin Scott from the dead.”

They seem to be proliferating and we’re seeing these diseases come back: an intentionally unvaccinated child recently died of diptheria in Spain, the first case seen there since the 1980s.  Then there was the measles outbreak that began in Disneyland last year, largely fueled by families that had refused to vaccinate their children.

While unrelated scientifically (do I need to repeat myself, MMR vaccines never had thimerosal as an ingredient), these three events became the bedrock of the modern anti-vaccination movement. The headlines falsely claiming that vaccines cause autism spread quickly throughout the Western world, and vaccine rates plummeted.  Once it’s out there you can’t get the genie back in the bottle.

The reality is that vaccine programs have been heralded as the greatest medical innovation of the last hundred years. We have drastically decreased deaths from vaccine preventable diseases. Even cervical cancer is getting its butt kicked. We need to keep it that way.

Editor’s Note 2.16.17 | This post was updated to better reflect the difference between the historic uses of elemental mercury.

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Categories: Disability + Disability Advocacy, Infectious Disease + Vaccines, Science 101 + Mythbusting

What is Arsenic Doing in Rice Cereal?

By April 5, 2016 No Comments

This week the FDA released a consumer update called Seven Things Pregnant Women and Parents Need to Know About Arsenic in Rice and Rice Cereal. While many parents were caught off guard by the new recommendations, I was lucky enough to be talking to pediatricians, PhDs, registered dietitians, clinical professors, and even the 18th United States Surgeon General about what the guidance actually meant for families.

That’s because I work for the International Food Information Council Foundation (aka We’re a nonprofit educational foundation and receive funding from companies that support our mission, other foundations and associations, government grants, and individual donors. But, as the phone calls and texts from friends and family members can attest, not everybody gets the benefit of having teams of experts at their fingertips to put scary headlines in context. In response to the crazy headline frenzy, I wanted to pitch in here at The Scientific Parent with what I’ve learned, and help answer questions about the FDA announcement:

Isn’t arsenic in rat poison? Why would any level of it be ‘safe’ to feed to my baby?
I completely understand why arsenic sounds so scary- I mean, it’s what elderly aunts used to poison Cary Grant (ok, IMDB reveals I’m misremembering this plot, but the point stands). Arsenic is actually a naturally occurring metal found in soil and water, and it’s a classic example of ‘the dose makes the poison.’ For example, too much Vitamin D (40,000 IU/day everyday for 3 months or more) can cause hypercalcemia which can create kidney stones and interfere with critical body functions. But getting the right amount of Vitamin D doesn’t put you at risk for these symptoms at all. Sense About Science also has a great example – pears contain formaldehyde, but in such a small amount as you would consume in a pear, it wouldn’t harm you.

That’s all to say that with trace amounts of arsenic found in rice and other foods, it really is all about the level of exposure. Arsenic isn’t avoidable; as Dr. Julie Jones, Distinguished Scholar and Professor Emeritus on Foods and Nutrition at St. Catherine University, said “it’s found in vegetables, fruit, rice, grains, fish and anything made from them like juices, beer, and wine. […] If you cut arsenic from your diet, you’ll die of starvation.” Luckily, it doesn’t need to be totally avoidable for you to keep your family safe and healthy.

Why is this issue just being addressed now?
The FDA has been testing for total amounts of arsenic found in food, including rice, through its Total Diet Study program. About five years ago, new scientific methods were developed to test organic versus inorganic arsenic, and so the FDA expanded its testing. (Inorganic/organic isn’t related to growing methods- both types occur naturally, and inorganic arsenic is the type that, in large amounts, causes adverse health impacts).

The FDA then released a broad set of test data for levels of inorganic arsenic in rice foods in 2013. What was released last week was another, deeper risk assessment than the one in 2013. The FDA has also made clear that their current recommendations are out of an abundance of caution and prudence, and not due to any kind of emergency scenario or health threat.

Leslie's son plays with rice he had just spilled.

Leslie’s son plays with rice

How would I know if my infant is getting too much arsenic? If I’ve fed them rice cereal is there a chance they’ve been permanently damaged or poisoned by it?
The FDA’s guidance is totally consistent with existing guidance from the American Academy of Pediatrics: feed your baby iron-fortified cereals, since iron prevents anemia and is essential for healthy movement of oxygen through the body; mix up rice cereal with other cereals like oat, barley, and multigrain; and feed toddlers a well-balanced diet that includes a variety of grains.

Adding lots of variety in your kids’ diets is a great idea for so many reasons- it gets a more diverse set of vitamins into the mix, it helps kids develop their taste and texture experiences.

This means there are no changes needed to your infant’s diet based on the recent arsenic data, nor have they been permanently damaged or poisoning by it by following AAP (and likely your own pediatrician’s) food guidelines. The biggest risk factors associated with our diets are often the most obvious – almost nobody is getting an ideal amount of vegetables – so focusing just on rice doesn’t make much sense.  Take this opportunity to add variety throughout your diet and amp up your protein, veggies, and all kinds of whole grains.

Can arsenic build up in the body like lead?
Nope. Scientists agree that the body has a way of processing trace amounts of inorganic arsenic ingested through food and water and converting it to organic arsenic, which is of less concern. Ultimately, the majority of ingested arsenic is rapidly excreted in your urine within a few days.  It does not accumulate in the body.

Is this a problem only with rice that originates in China? Is rice grown elsewhere safe?

Arsenic is a metal that’s found naturally in soil and water, so the FDA’s guidance isn’t about certain imports or Chinese rice- it’s about mitigating risks from rice grown anywhere. The level of arsenic can vary based on the soil type and the product, but you don’t need to specifically avoid any imported and regulated product for this reason – they’re all safe when they’re eaten in a diet with variety. For instance, brown rice has slightly higher levels of arsenic than white rice, but, since brown rice is a whole grain, its overall health benefits are much greater. Dr. Julie Jones emphasized that whole grains like brown rice offer benefits in combating risks of heart disease, gastrointestinal cancer, and diabetes. Those benefits actually counteract any small risks that would come from trace amounts of arsenic.

What does this mean for your kids?
As Dr. Claire Chehrazi, pediatrician and mom, said “I have served rice foods to my son since he was about 5 months old and continue to do so, especially given the health benefits of whole grains like brown rice. I counsel parents to educate themselves so that they can make decisions they’re comfortable with, and I do encourage rice, especially whole grain brown rice, as part of a healthy and balanced diet.” As previously mentioned, iron-fortified cereals are a must, including rice cereal, and whole grains like brown rice are a great addition to your diet. Combine them with a variety of grains and grain cereals.

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Categories: Food, Nutrition, + Infant Feeding, Newborns + Infants, Policy, Politics, + Pop Health

Is Fluoridated Water Dangerous?

By March 30, 2016 1 Comment

A neighborhood kid once caught hand, foot, and mouth disease from my daughter before we had any signs that she had it. Her mother scolded me and asked me to please alert them next time my daughter was sick.


I don’t blame her for being protective. That illness is a doozy, as many of you likely know from experience. But being reprimanded by another parent when both our toddlers were so sick just made the whole thing worse.

This in-person interaction made me feel awful and I quickly turned to my virtual support network to share my thoughts and for reassurance. And I’m not unique.

As anxious parents, we persistently echo our worries and stories through blogs, videos, and other social media outlets. Connecting with other parents through social media provides us with important support, and even desperately needed humor! Being a parent can be isolating, so seeing our own beliefs and experiences reflected back on social media can be reassuring. This can be helpful when we feel vulnerable like I did when another mother chided me, but it can also be harmful.

As a professor of Oral Health and Epidemiology at the Harvard School of Dental Medicine, my research demonstrates that what is shared across the Internet often contradicts scientific consensus and current knowledge on a variety of health topics. It can be comforting to hear our own beliefs reflected back to us, but it’s harmful when those beliefs aren’t accurate.

Nearly 80% of us search for health information online. The internet is a rich network of information, but also of misinformation. A lot of this misinformation has shaken parents’ confidence in some of public health’s greatest achievements, including fluoridated water. One of my favorite quotes, from Thomas Patterson, Bradlee Professor of Government and the Press at the Harvard Kennedy School, states, “The internet is at once a gold mine of solid content and a hellhole of misinformation.”

Last year, we celebrated 70 years of community water fluoridation in the United States. Over 120 of the world’s leading health, dental, and medical organizations praise the success and benefits of fluoridation. As a dentist, water fluoridation is a topic I am very familiar with and it’s one that there’s a lot of misinformation about on the internet. Often parents ask me the same five questions about water fluoridation, but most of us don’t have easy access to a dental epidemiologist, so I’ll answer them for you here, from one parent to another:

1) Is fluoridated water safe to drink? Yes.
From time to time, you will see a scary-sounding study float fluoride-infographic-how-it-worksacross your Facebook page. But it’s important to
remember that expert consensus and an enormous body of sound, scientific evidence continue to find that fluoridated water is safe and does not contribute to or cause illness or disease.

The Facts:

  • A U.S. Public Health Service review of data and research concluded, “Expert panels which reviewed the international body of literature agree that there is no credible evidence of an association between either natural fluoride or adjusted fluoride in drinking water and human cancer.”
  • The consumption of fluoridated water has not been shown to cause or worsen conditions of the thyroid, kidney, heart, or other glands/organs. The only proven risk associated with excess fluoride is a cosmetic condition known as dental fluorosis. (See below.)
  • For more information, see Common Questions about Fluoride.

2) If Fluoride is a chemical, why is it safe to have in our drinking water? 

When we use the word ‘chemical’ we sometimes take it to mean dangerous, but the truth is that everything that occurs naturally (and man-made) has a chemical structure, even water and oxygen.

Fluoride is a naturally occurring element in all water sources; some fluoride levels are too low for any dental benefit and some sources are very high. Fluoridation is the process of adjusting these levels for optimal dental benefit while minimizing risk for fluorosis.

3) Is fluoridated water safe for children, babies, and formula-fed infants? Yes.

Parents often ask me if fluoridated tap water is safe to mix formula for their infants or if they need to purchase distilled or bottled water. If you’re on a municipal water supply and there aren’t unrelated issues with the safety of your tap water (as in the case in Flint, Michigan), fluoridated tap water is safe for children, babies and formula-fed infants.

 The Facts:

  • The American Academy of Pediatrics (AAP), the American Dental Association (ADA) and the Centers for Disease Control and Prevention (CDC) are among many who agree that water fluoridation is a safe and effective way to prevent tooth decay in children.
  • According to the ADA, it is safe to use fluoridated water to mix infant formula. The risk if mixing infant formula with fluoridated water is mild fluorosis. (See below.) If you have concerns, talk with your pediatrician and dentist.
  • For more information, see Fluoride and Children.

 4) Does fluoridated water negatively affect IQ or children’s developing brains? No.

Between the 1940s and the 1990s, the average IQ scores of Americans improved 15 points – at the same time that fluoridation expanded to serve millions more people. To be clear, this is a case of correlation, not causation. There is nothing in the peer-reviewed literature to suggest fluoridated water has caused the increase in IQ scores. Some have claimed that fluoridated water has decreased IQ scores in the US, and we know that’s just not true as American’s IQ scores have risen alongside the use of water fluoridation.

The Facts:

  • Many point out a study known as the ‘Harvard study’ (ironic, I know), which postulated an inverse relationship between fluoridated water and IQ. It’s important to note that this study looked at the IQ scores of children in China, Mongolia and Iran and in many of these areas, the water had exceedingly high levels of naturally occurring fluoride – as much as 10 times higher than levels used to fluoridate public water systems in the U.S.
  • The study did not test cause and effect or conduct research designed to explain a possible relationship between fluoride and IQ. Numerous experts have debunked this claim, myself included.
  • For more information, see Does Fluoride Lower IQ Scores?

 5) What exactly is dental fluorosis? Should I be concerned about fluorosis from drinking fluoridated water?

Dental fluorosis is a change in the appearance of the teeth, typically in the form of very faint white markings. It does not affect the function or health of the teeth. In fact, teeth with mild fluorosis are more resistant to cavities.

Fluorosis is the result of consuming too much fluoride while teeth are forming, before the age of 8, particularly if children swallow fluoridated toothpaste. The American Dental Association recommends specific quantities of toothpaste according to age, in order to minimize the risk of fluorosis. For optimal dental health, provide water fluoridated at the recommended levels and supervise brushing so that children learn to spit, not swallow.

 6) How much fluoride do children need? What are the recommended levels?

The fluoride that is added to public water supplies conforms to stringent safety standards and results in water that complies with the Safe Drinking Water Act. The quality and safety of fluoride additives are ensured by Standard 60, a program that was commissioned by the U.S. Environmental Protection Agency (EPA). This program is monitored by an independent committee of experts, including the Association of State Health Officials and other key organizations.

In 2015, the Department of Health and Human Services recommended that the level of fluoride in drinking water be set to a uniform level (0.7 mg/liter) across the nation. This resulted from research showing no difference in water consumption in warmer climates and responded to the increased availability of fluoride from a variety of sources by reducing the amount contained in water. 

Take home message: Fluoridated water is safe. Children and adults who consume a typical diet, drink optimally fluoridated water, and use fluoridated dental products as recommended will not exceed the maximum levels for fluoride. And they’ll have healthier teeth!

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Categories: Policy, Politics, + Pop Health, Science 101 + Mythbusting

Is Monsanto Behind Cases of Microcephaly in Brazil?

By February 17, 2016 12 Comments

I am a medical doctor and professor of public health, and I am also the father of a beautiful daughter and uncle to the world’s best niece.  We also live in Rio de Janeiro, Brazil.  We are being inundated with information and misinformation about Zika and its correlation to microcephaly.  There is a lot of fear, which is the perfect environment for people to spread false information.

When I saw friends sharing an article based on fear and not facts, I knew I had to comment due to my background.  If you have not seen this article, you can read it here, but it claims the reported increase in microcephaly in Brazil is caused not by Zika or any other virus, but a larvicide called Pyriproxyfen.  Larvicides are used to kill mosquito larvae and since Zika is spread by mosquitoes this bit of misinformation could cost lives.

The article references a mysterious document purportedly written by “Argentine doctors.” The organization that undersigns it is the “Red Universitária de Ambiente Y Salud”, which is a loose affiliation of individuals dedicated to fighting the use of pesticides, agrotoxics and the like. Perhaps the biggest clue that the information in the document is not trustworthy is that the name of larvicide called into question is repeatedly spelled wrong throughout.

I will address the claims made in the executive summary of the document point by point.

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Categories: Ages + Stages, Chronic Illnesses + Conditions, Disability + Disability Advocacy, Infectious Disease + Vaccines, Newborns + Infants, Science 101 + Mythbusting

Caring for Sick Kids: Know the Difference Between “Natural Remedy” Facts and Fallacies

By November 18, 2015 3 Comments

It’s hard to watch our kids suffer when they’re not feeling well. c/o M. Weinberg-Anderson

Taking care of an ill child is challenging. On one hand, a parent wants more than anything in the world to relieve their child’s discomfort, but it’s also perfectly reasonable to have concerns about the potential side effects of prescription and over-the-counter medications. It is also completely understandable that many well-meaning parents seek out remedies that are marketed as being “natural” because they believe that these types of remedies will be safer than conventional treatments. Unfortunately, many of these concerns are unfounded, since most so-called natural remedies are ineffective or even unsafe, as I have explained in my previous post.

Before I address a few specific bogus remedies for sick children here, I want to tackle a few equally bogus claims that are often raised during discussions of alternative approaches to health care. Whenever I question the safety or effectiveness of a “natural” remedy, I am invariably faced with one or more of the following rebuttals: natural means safer, natural means more effective, and finally, doctors only recommend drugs and surgery. None of these generalizations are remotely true, and here’s why:

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Categories: Ages + Stages, Newborns + Infants, School-Aged Children, Science 101 + Mythbusting, Toddlers + Preschoolers, Tweens + Teens

Kids and Energy Drinks – 3 Things Every Parent Should Know

By October 7, 2015 6 Comments


Headlines like “Energy Drink Consumption on the Rise in Kids, Teens,” appear frequently in the news, a somewhat alarmist reaction to data released last year which measured caffeine consumption in minors over a ten year period. That study in question, published in Pediatrics in February 2014, showed how children’s caffeine habits changed from 1999 to 2010.

However, those headlines aren’t quite accurate, particularly with how they allude to it being an issue that is “out of control.” Unfortunately, this is just one of the latest examples of how the wrong details are emphasized in energy drink news stories, even in publications as reputable as Time magazine. There are three major details often left out of these conversations on caffeine which could dramatically boost our efforts to keep ourselves and our kids healthy and safe.

Caffeine Consumption in Kids and Teens is Not as Bad as it Seems

Taking a closer look at the Pediatrics study, it’s not surprising that energy drink consumption among minors has increased since 1999 – energy drinks such as Monster Energy and Rockstar didn’t exist back then! What is surprising is despite these reports, the total amount of caffeine consumed per day per person didn’t change after the energy­ drink boom.

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Categories: Ages + Stages, Food, Nutrition, + Infant Feeding, School-Aged Children, Science 101 + Mythbusting, Tweens + Teens

The Chemistry of Sunscreen: Organic vs. Non-Organic, a Marketing Misnomer

By August 12, 2015 2 Comments

A few weeks ago, I took my daughter to the opening of an outdoor portion of our local children’s museum.  As a service, the museum provided sunscreen for all who attended.  Not just any sunscreen, but natural, “chemical-free” sunscreen.  Several women near me were chatting about how nice it was that the museum provided “chemical-free” sunscreen.

The chemist in me rolled my eyes.  Why?  Because everything is made of “chemicals.”  So, it is a bit of a misnomer to call this sunscreen “chemical-free.”

The words “contains organic ingredients” also highlight the difference between language used in marketing versus the scientific community as a whole.  The word “organic” has many meanings but is often associated with living (or once-alive) organisms.  In chemistry, “organic” simply means chemical compounds associated with living species, specifically, a carbon backbone. Thus in chemistry, organic simply means “containing carbon,” while in the marketing world, “organic” often means “limited pesticides.”

Now that that misnomer has been debunked, what you need to know is that in the sunscreen world, two labels are used to describe it: “mineral” and “chemical” sunscreen. “Mineral” sunscreens typically refer to zinc oxide and titanium dioxide, which are chemical compounds labeled “inorganic” because they do not contain carbon atoms in their overall structure.  Conversely, “chemical” sunscreens are made up of carbon-containing molecules that absorb light, and because they contain carbon, chemists refer to them as “organic.”

Below is the chemical structure for oxybenzone.  When an organic molecule has a lot of double bonds like you see below, it’s good at absorbing UV light, the same light that we are trying to block using sunscreen (absorbing in this case means the same as blocking). This is what makes oxybenzone a good sunscreen.


(Drawn using Chemdoodle,

The green sunscreen shown above is the one given to us by the children’s museum, and it contains zinc oxide (ZnO), and titanium dioxide (TiO2). These are also chemicals, just a different type of chemical.  ZnO and TiO2 are not carbon-containing molecules (“organic”), but rather inorganic UV blockers.  Many sunscreen brands refer to zinc oxide and titanium dioxide as “mineral” sunscreens.  This term evokes thoughts of gathering rocks and grinding them up and plastering the mix on your body.  But this actually is a bit of marketing language.  Zinc oxide and titanium dioxide are also chemicals.  In fact, they’re chemicals not typically even found in nature, but rather created or synthesized in the lab by oxidizing zinc and titanium metal.

(Drawn using Chemdoodle,

(Drawn using Chemdoodle,

So what are the pros and cons of each type of sunscreen?

Pros and cons of oxybenzone sunscreen: Oxybenzone is a clear sunscreen, meaning that it is relatively easy to apply and does not have a white appearance. Most importantly, oxybenzone absorbs UV light and protects your skin from UV damage, which makes it a good sunscreen.  The drawbacks of the UV-absorbing organic compounds include a higher rate of allergic reactions in users and the possibility of the compound being disruptive to hormones such as estrogen. Although studies show that oxybenzone  does bind to estrogen, panic associated with this finding is unfounded.  In 2004,  a study that found that while humans absorb oxybenzone, there was not enough evidence to suggest that the absorption of oxybenzone affected hormone levels.  In my professional opinion, the benefit of oxybenzone protecting your skin from harmful UV rays outweighs the small risk that oxybenzone may be a hormone disruptor.

Pros and cons of Zinc oxide and Titanium dioxide sunscreen: Zinc oxide and titanium oxide sunscreens are also both very effective at blocking UV light from your skin through a combination of scattering and absorbing the UV light. However, the biggest drawback of zinc oxide and titanium dioxide is their cosmetic appearance.  Both of these compounds are white and produce an opaque appearance on the skin.  Even with advances of making ZnO and TiO2 particles very small (i.e. to make them more translucent), the opaqueness is still an issue for those who prefer invisible protection.

I personally use both types of sunscreen for myself and my children, so my recommendation?  Use sunscreen.  Any type that you can find or afford.  It would be much better to use any type of sunscreen than none at all – just make sure that your children are protected to prevent sunburns.




Burnett, M. E. and Wang, S. Q. (2011), Current sunscreen controversies: a critical review. Photodermatology, Photoimmunology & Photomedicine, 27: 58–67.

[2] Schauder, S.,  Ippen, H. (1997) Contact and photocontact sensitivity to sunscreens. Review of a 15 year experience and of the literature. Contact Dermatitis, 37, 221–232

[3] Janjua, N. R., Mogensen, B., Andersson, A., Jørgen, H. P., Henriksen, M., Skakkebæk, N.,E., & Wulf, H. C. (2004). Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans. The Journal of Investigative Dermatology, 123(1), 57-61.



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Categories: Science 101 + Mythbusting

PART 2: Can Bananas Make You Bleed to Death? Will BHT in Kids Cereal Cause Cancer? What is Chemophobia?

By May 19, 2015 2 Comments
All Natural Banana

Everything is made of chemicals, even an all-natural sun-ripened banana. Does a banana naturally include a chemical used by big pharma and a chemical that can cause your blood to stop clotting?! Image via James Kennedy. CLICK TO ENLARGE

In Part 1 of this two-part series, I addressed The Food Babe’s allegation that said if your food contains an ingredient your third grader can’t pronounce you shouldn’t eat it – and my stance on that is, then no one would ever eat an organic banana, which contains naturally-occurring phylloquine, tocopherol and palmitoleic acid, which are tongue twisters.

Today in Part 2, as we continue our BHT discussion, let’s start back at that example of our all-natural organic banana.  What if I was to tell you that the same chemical found in bananas, that has been shown to cause a 7% increase in lung cancer in non-smokers, has also been found to act as an anticoagulant in large doses and can cause bleeding issues?  Yes, it’s tocopherol again. You would need to eat 5,000 bananas in one day to reach the levels (1,000mg) that cause bleeding issues. If you eat a banana or two a day, you won’t develop bleeding issues, as the dose makes the poison.

Using that frame of reference, many research groups have tested the hypothesis that BHT contributes to cancer.   Most reports discuss BHT feeding trials in rats, and the data follow two central trends:

The first is that the tumor incidence observed in small studies is not replicated in larger studies.  In science we need our sample sizes to be considered ‘representative’ in order to be considered ‘generalizable.’  That means that we need a large sample population in order to say that the findings can be applied to the general population.  This is because small sample sizes are prone to sampling errors.  A study’s findings are problematic when you see a result in a small sample population but don’t see those same results in a larger population.  In this case we’d want to see the same patterns in both the small and larger studies, but we don’t.  But, small studies are subject to statistical noise, as a blip in the particular set of rodents makes results appear to be significant—yet they don’t repeat in a larger statistical set.

The second trend observed is what scientists refer to as a dose-response failure.  This basically means that if a small amount of a test compound causes a problem, then higher amounts should cause an equal or greater response.  It makes sense, as I said above, that the dose can make the poison.  Taken in total, there is absolutely no credible evidence that BHT causes cancer in animals, and the IRAC notes its carcinogenicity as “inconclusive”, which means nothing has been observed. Some studies in petri dishes are suggestive, but not conclusive about a BHT cancer risk.

Other BHT feeding studies in monkeys were shown to induce potent effects on the liver, resulting in physiological and cellular abnormalities.  However, these studies fed monkeys 500 mg/kg of body weight of BHT for 50 days.  That’s akin to a 200lb person eating 50 g (the weight of a tennis ball) of BHT every day for 50 days.  The average American consumes approximately 2 mg/day, or 25,000 times lower (per day) than the amount shown to induce these problems in primates.  Lung problems were observed in dogs and mice when they were given 75,000-100,000 times the human daily intake.

Of course, there are many fear mongers in the anti-additive space that don’t understand the science.  They read the headline or article title and draw a conclusion.  These interpretations are not consistent with the science, yet they spread like wildfire throughout electronic media.

Ironically, there are just as many papers that suggest preventative effects from BHT.  Of course, these are no fun for fear mongering and are also rather preliminary science, so you don’t have too many health advisers suggesting increased consumption.

Like any chemical added to food it is critical to carefully consider the benefits and risks at realistic concentrations encountered.  As I said in my previous post, it is certainly easy to read the reports on risk assessment and toxicity and become worried about possible effects, as they do seem so plausible.  However, I reiterate, that careful analysis reveals that biological effects are not observed at the levels actually consumed in the typical diet.  BHT, like most food additives, is present in vanishingly low amounts, and its benefits as a product to keep food fresh far outweigh any risks.

While I’m not a parent myself I’m very close to my niece and feel protective of her.  I have given her food with BHT in it and I’m not concerned about the long-term impacts on her health, or my own.  I also give her bananas, and I’m pretty sure she’ll be OK.


Editor’s Note 2.7.17: After this post was published Dr. Folta came under attack for alleged financial conflicts of interest. These allegations were later found to be misrepresented. In response to reader questions after the initial allegations we added an editor’s note on his articles on this site that acknowledged the claims, but reiterated the scientific accuracy of his writing for As the claims have been debunked we have removed our original editor’s note.



Wikipedia. Chemophobia Entry. Retrieved May 17, 2015.
Office of Dietary Supplements. Vitamin E Fact Sheet for Health Professionals. National Institutes of Health. Last reviewed June 5, 2013. Retrieved May 18, 2015.
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS). Scientific Opinion on the re-evaluation of butylated hydroxytoluene BHT (E 321) as a food additive. European Food Safety Commission. EFSA Journal 2012;10(3):2588. Retrieved May 17, 2015.
Wu, QJ. Xiang, YB. Yang, G. et al. Vitamin E intake and the lung cancer risk among female nonsmokers: a report from the Shanghai Women’s Health Study. International Journal of Cancer.2015 Feb 1;136(3):610-7. doi: 10.1002/ijc.29016 Retrieved May 17, 2015.
National Toxicology Program. Bioassay of Butylated Hydroxytoluene (BHT) for Possible Carcinogenicity (CAS No. 128-37-0). U.S. Department of Health and Human Services. Report date, 1979. Retrieved May 17, 2015.
Malkinson, A., Koski, K., Evans, W. et al. Butylated Hydroxytoluene. Exposure Is Necessary to Induce Lung Tumors in BALB Mice Treated with 3-Methylcholanthrene. Journal of Cancer Research. July 15, 1997. Retrieved May 18, 2015.
United States Environmental Protection Agency. Dose-Response Assessment. Last updated July 31, 2012. Retrieved May 18, 2015.
Matsuo, M., Mihara, K., Okuno, M., eat al. Comparative metabolism of 3,5-di-tert-butyl-4-hydroxytoluene (BHT) in mice and rats. Journal of Food Chemistry and Toxicology.1984 May;22(5):345-54
United States Food and Drug Administration. Select Committee on GRAS Substances (SCOGS) Opinion: Butylated Hydroxytoluene (BHT). Last updated April 18, 2013. Retrieved May 18, 2015.
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Categories: Food, Nutrition, + Infant Feeding, Science 101 + Mythbusting