I am a person who worries a lot. A huge part of my goal with ParentData is to create a world in which the rest of you can worry less because I’ve done some of the worrying (and research) for you.
Parental worries come in many flavors. There are things you should worry about, like being near a pool with a kid who cannot swim. There are things you shouldn’t worry about at all, like whether it’s okay for your kids to watch 30 minutes of TV so you can take a shower (it’s fine).
And then there are things that are concerns, but which we have limited control over. For example: asteroids. It’s possible that right after you read this, a city-size asteroid will destroy human civilization, but there is no point in worrying about this. Not only because it’s very unlikely but also because you cannot do anything about it. Worrying about this just makes you upset and anxious for no reason.
One of the key things I have learned from worrying a lot, and trying to worry less, is that it’s often a very good idea to think not only, How concerned should I be? but also, Can I take actions to affect this?
Which brings me to today’s topic: phthalates.
What are phthalates?
For those of you who are not, say, chemistry majors, phthalates are a class of chemicals that are added to many, many plastics to make them more flexible. They are ubiquitous in the products we use, and evidence of them (in the form of metabolites) appears in most tested urine. Many concerns have been raised that they have health impacts, notably on reproductive health, endocrine health, and cancer.
This discussion is not new. Concerns about these and related chemicals have been around for decades, and it’s easy to find a lot of sources suggesting you should be concerned. But how concerned? And about what?
Before we get into these answers, a note on terminology: There are a lot of different phthalate ester compounds, with names like DMP, DEP, and BBzP. These are different chemicals but in the same class. Talk about “phthalates” tends to mean one or many of these.
Where does exposure to phthalates come from?
Phthalates are ubiquitous in consumer products. They are used to make plastic flexible, and they appear in hair care, garden hoses, medical tubing, and on and on. The two areas where concerns are most often raised for human exposure are food and cosmetics.
To begin with food: A 2013 paper made a valiant effort to identify phthalates in foods. To do this, the researchers purchased food in various New York supermarkets and tested it. They compared all kinds of foods (juices, teas, soups, fish, meat, bread, etc.) and tested for a large number of different phthalate esters.
Low concentrations of these chemicals were found in basically all foods. Packaged grains, dairy products, and meats were among the higher-concentration groups, but all food groups contained pretty similar levels. Some of the findings were unpredictable. For one phthalate, an extremely high concentration was found in one particular olive oil. For another, there was an especially problematic ham sample. But ham, in general, wasn’t a significant source, nor was oil.
On the plus side, the overall concentrations in foods were small. More concerning to many people, though, is the ubiquity: So many foods contain these chemicals that avoidance is a challenge. Food packaging has similarly, and more recently, been shown to have widespread phthalates.
Another commonly cited area of exposure is personal care products. It is well-known that phthalates are used in packaging for these products, and research has shown that the use of these products by kids increases phthalates in their urine.
You are also exposed to these chemicals through drinking water and in many other ways.
There are a lot of concerns raised about phthalates; they’ve been linked to a myriad of health problems. In many cases, the quality of the evidence on the links is not very compelling. Groups with higher exposure differ in many other ways; here’s an example in the case of cancer. But there are two concerns that come up often enough to deserve more discussion: declining sperm counts and an increase in behavioral issues in children.
Concern #1: Do phthalates decrease sperm counts?
Let’s begin with sperm, where phthalates have been blamed for declining levels.
To begin, the change in sperm counts is real. Sperm counts have been dropping over the past decades. This basic time trend is not difficult to study (sperm is easy to get), and there are good articles (like this one on Chinese sperm donors) that demonstrate large changes in sperm count and quality over time. The extent to which sperm count impacts fertility is not completely clear. There are studies that show that while older men have a lower sperm count, they are no less likely to fertilize eggs in IVF. Of course, in the limit, you have to imagine it does matter for fertility.
Despite general agreement about the presence of this decline, the reasons are poorly understood. There are a lot of things that affect sperm count and quality. Here’s an excellent review article that cites all of the following possible influences: alcohol, smoking, caffeine, illegal drugs, diet, supplements, being overweight, being underweight, heat, zinc, copper, selenium, water pollution, other pollutants, pesticides, phthalates, glycol ethers. Tight underwear also plays a role.
How important are phthalates, specifically? It’s really hard to know. Research that studies this measures evidence of phthalate exposure through urine testing and then correlates the concentration of various phthalate metabolites (by-products of exposure) with outcomes. The evidence based on this is a bit mixed and depends on the method of measurement and the particular metabolite considered. Moreover, the extent of exposure to phthalates is likely correlated with other lifestyle and environmental risks, making the individual association difficult to untangle.
Conclusion: We do not really know if phthalates play a role in these declining counts, and there are many other factors that matter.
Concern #2: Do phthalates increase the risk of behavior problems in children?
For children, the more commonly cited concerns are about behavior regulation, in particular the question of whether exposure to phthalates, either in utero or in childhood, increases the risk of ADD/ADHD or other neurodevelopmental conditions.
There are a number of studies on this. Most frequently, these studies focus on in utero exposure: They measure the concentration of phthalates in the urine of pregnant women and then look at neurodevelopmental outcomes for their children.
Frankly, the results from these analyses are a bit all over the place. This 2019 review is a good summary. There are many different phthalates (as in, many different chemicals in this class). Papers tend to look at all of them, and it’s hard to get consistent evidence. There are certainly papers that show negative associations between various of these chemicals and cognition. But there are also papers that show positive associations. Some show positive associations for girls and negative for boys; others the opposite. If you read this whole review, most of the paragraphs sound like this one:
Exposure to BBzP during pregnancy affects cognition, psychomotor, and language development in children, but the studies are controversial. Gascon et al. (2015) showed a negative association between MBzP and psychomotor development; Doherty et al. (2017) found that MBzP was positively associated with cognitive development in boys and negatively associated with psychomotor development in girls; while Ipapo et al. (2017) and Olesen et al. (2018) respectively found that prenatal exposure to BBzP was not advantageous to girls’ visual recognition memory or boys’ language development. However, Tellez-Rojo et al. (2013) reported that MBzP was positively related to psychomotor development among boys. The other birth cohort studies found no association between BBzP and children’s neurodevelopment.
The combination of outcomes, genders, different chemicals — the picture is messy and inconsistent.
The exposure in utero is a primary concern, but there are papers that measure phthalates in child urine and correlate with behavioral issues. Again, we see associations for some chemicals and not others, sometimes for girls and other times for boys. Also worth noting: All of these studies (in utero and out) are subject to concerns about bias — none are randomized, and exposure to these chemicals may differ across demographic groups.
What to take from this? What I take is that any impacts are likely to be small. If there were large impacts from any of these chemicals on any outcomes, we would see them consistently showing up across studies. That we do not, and that the results are so varied, makes it hard to definitively rule out any relationship. But it also makes it unlikely there is anything substantial.
Is it possible to avoid phthalates? What can be done?
Phthalate exposure is ubiquitous. They’re everywhere. Nearly everyone has phthalate exposure to some extent. Even the people who are really, really good about using glass jars to store stuff in.
Most of the changes you might make as an individual are likely to be large sacrifices for small gains. Completely avoiding beauty products might lower your exposure to some extent but certainly not eliminate it. Even if you go full-on Ballerina Farm and make your own meatball subs with homemade meatballs, cheese, and sourdough bread, you’ve probably still got some phthalate exposure from the meat packaging.
There is a policy push toward the reduction and monitoring of these chemicals. The EPA has a proposal up for public discussion that aims to develop a framework to evaluate cumulative risk from these products. The FDA has found that companies are reducing their use of these chemicals in food production (although replacing them with other ones). This policy, rather than individual choices, is likely the primary way phthalates will decrease.
How concerned should you be about phthalates?
From a health standpoint, there is no smoking gun here. The idea that chemicals are in your urine and bloodstream freaks people out – I get it! – but the data doesn’t support the need for that level of panic. That isn’t to say that these chemicals are a plus. There is no reason to think they enhance human health, and thoughtful attempts to reduce human exposure seem reasonable.
However, there are two reasons I think individuals should not worry here. One is that the demonstrated health effects are small and inconsistent. The other is that there aren’t any productive actions you can take. You could stop using shampoo, but the impact of that choice on your level of exposure is vanishingly small. It might be a performative choice, but it would not be a productive one.
There is something hard about acceptance. To sit with the idea that these chemicals aren’t a plus, that they might have small negative effects, but that there is nothing significant you can do (at least not that makes sense with your life) … that’s just a challenge.
At the end of Cribsheet, I tell a story about bees. In brief, it is a story of the time I forced our lovely pediatrician to listen to my lengthy narrative panic attack about whether we needed to bring an EpiPen on vacation just in case Penelope was stung by a bee and it turned out (despite no reason to think this) that she was allergic. Dr. Li paused and then delivered what I still think was the best parenting advice I’ve gotten: “Yeah, I’d just try not to think about that.”
It wasn’t that bee allergies weren’t a real thing, just as it is not necessarily true that phthalate exposure is completely benign. But there really wasn’t anything to do about this, and in the space of all the other concerns one might have, this was small. So, maybe, just try not to think about it.
The bottom line
- Phthalates are a class of chemicals that are added to plastics to make them more flexible. They are ubiquitous in the products we use (the two areas where concerns are most often raised for human exposure are food and cosmetics).
- One of the main concerns about phthalate exposure is that it can negatively impact sperm counts. We do not really know if phthalates play a role here, and there are many other factors that matter.
- For children, the more commonly cited concern is whether exposure to phthalates, either in utero or in childhood, increases the risk of ADD/ADHD or other neurodevelopmental conditions. The data here is mixed, but ultimately conclude that any impacts are likely to be small.
- There is really no way to avoid phthalates completely. Most of the changes you might make as an individual are likely to be large sacrifices for small gains. The primary way phthalates will decrease is through policy changes, not individual choices.
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So maybe one way to put it is: the action one should consider taking is collectively advocating for better consumer protections from phthalates rather than trying to individually protect ourselves through purchasing choices.
I read this as someone who lives a couple miles from an unresolved Superfund site that just got new contamination from a forever chemical spill from a not-uncommon old firefighting foam. In this scenario, there *are* personal actions people have needed to do, in some circumstances: people with well water in the vicinity need ongoing testing. And nearby, some parents fed their children meat from a family farm found to have disastrously high levels of forever chemicals, and the children now have freakishly high cholesterol, which is attributed to their consumption of this meat. Our state, Maine, is a leader in testing for the chemicals, and shutting down farms that test too high. We also routinely test public drinking water. These are steps that other states could take and things people could push for.
I’m somewhat puzzled by the urine level thing, as what scientists have said is that the risk is from ingestion, not skin contact, so showering with PFAS water is fine. Is it that young children put a lot of stuff in their mouths? Or is skin contact actually a risk?
This comment is about PFAS (colloquially referred to as forever chemicals) but the article is about phthalates. Your questions about urine level make me wonder if you might have confused the two here? PFAS & phthalates are going to have different pathways for exposure.