Do Chemicals Impact our Hormones and our Health?
They are in the air we breathe, the food we eat, the products we apply to our skin, and the mattresses we sleep on—and mounting research indicates that they’re in our blood and urine as well.
As awareness of the potential impact of chemical exposure increases, concern over the issue and the need for accurate information and research is becoming more widespread. So, what do we need to know about how these pesky, toxic hitchhikers just might be affecting our health—and, most notably, our hormones?
For those of us who didn’t excel in chemistry, the mere mention of compounds like bisphenol A (BPA), phthalates, and tributyltin (TBT) can make our eyes glaze over. It’s tempting to tune out—ignorance is indeed bliss; however, it may be more important than ever to pay attention.
Women tend to accumulate higher levels of many toxins in their bodies compared with men.1 This can be particularly significant in pregnant and lactating women because the developing fetus and nursing infants are more vulnerable to the harmful effects of many chemicals. Some chemicals have been linked with a variety of conditions, such as asthma, cancer, and impaired brain development—but one of the most pressing concerns about chemicals is their impact on the endocrine, or hormonal, system. A 2009 scientific statement from the Endocrine Society identified a variety of endocrine-disrupting chemicals that affect male and female reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid, metabolism, obesity, and cardiovascular endocrinology.2
Why does it matter if our hormones are disrupted? Hormones affect just about every action in the body. Our cells release hormones, which are like messengers that communicate with the brain, organs, glands, muscles, and other tissues in the body. Hormones regulate important bodily functions such as growth, mood, digestion, respiration, sense of thirst and hunger, fat metabolism, and sexual function. In other words, hormones are a key component of the finely tuned processes under way in your body at all times—and when you upset one component of a system, it can have a domino effect. What’s more—hormones are particularly important during fetal and infant development because normal hormone function is necessary for normal development. Adults are much less sensitive than infants to changes in hormone function.
There is a growing body of data to show that some chemicals pose health risks—but it’s a tricky area of research. In the scientific community, randomized controlled clinical trials are the gold standard—meaning that one group is given some sort of intervention (such as exposure to a type of medication) and another is not and then the two groups are compared. But environmental exposure does not happen in a controlled environment like that.
“With regard to a lot of environmental exposures, we don’t have a natural control group because often everyone is exposed,” explains Connie Engel, science and education manager for the Breast Cancer Fund, a national nonprofit organization dedicated to preventing breast cancer by eliminating exposure to toxic chemicals and radiation linked to the disease. “We can’t control who is exposed, and we certainly can’t do a randomized study and randomly assign people to things that we think are hurting them.”
Ted Schettler, MD, MPH, science director of the Science and Environmental Health Network, explains that the exposure to chemicals is widespread. “The reality is that there are hundreds of industrial chemicals in the cord blood of babies born throughout the United States,” he says. “Pregnant women carry measurable levels of chemicals. These are known facts. The Centers for Disease Control (CDC) does those kinds of studies.”3
The challenge comes in proving beyond a shadow of a doubt that these measurable levels of chemicals in our bodies actually pose a risk. The data have to show a correlation between increased levels of chemicals and health issues—and it is beginning to. Correlation is not the same as causation—and what causes a lot of political debate is the extent of causal linkage that must be established before taking action against a specific chemical. Of course, human studies are the most credible, but Engel says that if you look at the full body of data—which includes both human and animal studies—there is biologically plausible concern regarding chemicals.
“One of the most contentious chemicals right now is BPA, which is present in the blood or urine of nearly everyone in the United States—93 percent, according to the CDC,” Dr. Schettler says. “If everyone is being exposed to this, we need to know if it’s safe. We know that early-life exposure to BPA can alter the development of breasts and prostate in animals; but we don’t have—and we are never going to have—human studies that tell us what early life BPA exposure does to the breast or prostate years later in humans. It just isn’t going to happen. So, the problem we’re facing is that we have to deal with the data we have.”
The Health Risks
The data we have—both human and animal studies—indicate that it might be time to start paying more attention to chemicals that are considered endocrine disruptors, as they have been linked to breast cancer, obesity, thyroid disorders, and more.
Researchers from Boston University found that teen girls with higher levels of phthalates in their urine had a higher body mass index than those with lower levels.4 Another study, at Brigham and Women’s Hospital in Boston, found a link between phthalates and diabetes.5 In fact, the link between some endocrine disruptors and weight is so strong that one researcher, Bruce Blumberg, PhD, coined the term obesogens to refer to them. Obesogens activate a receptor called PPAR-gamma, which is the master regulator of fat cell development. So far there are about 20 known obesogens, including BPA, phthalates, perfluorooctanoic acid, and TBT.6,7,8
How Exposure Happens
We are exposed to endocrine disruptors on a daily basis in a variety of ways—in food, cosmetics, cleaning products, dust, and more.
Some of the most ubiquitous endocrine disruptors are BPA and phthalates. BPA is widely used in food and beverage packaging and can be found in things like canned soup, plastics, and even cash register receipts. The United States has banned the use of BPA in baby bottles, while other countries have banned its use entirely. Phthalates are used in, among other things, building materials, cosmetics, detergents, surfactants, pharmaceuticals, and children’s toys.
We absorb endocrine disruptors in a variety of ways, such as by eating them, drinking them, breathing them, and even absorbing them through our skin—by using a product such as a lotion or through contact with something as innocuous as a cash register receipt.
“There is no question about it—many chemicals in personal care products can be easily absorbed through the skin,” Dr. Schettler explains. Anyone who doubts this has only to look at the variety of transdermal products, such as nicotine patches, on the market today.
But even if you aren’t a heavy consumer of manufactured products, you’ll likely face exposure. In fact, even pregnant women in the Old Order Mennonite community—a Christian group that avoids a modern lifestyle—have been found to have detectable levels of BPA and phthalate metabolites in their urine, albeit far less than those who fully participate in modern society.9 These women rely mostly on fresh, homegrown food; farm without pesticides; and rarely use personal care products. Yet 70 percent of them had detectable levels of BPA, and 100 percent had detectable levels of phthalates.
In the current system, most chemicals are deemed innocent until proven guilty—in other words, they are put into use until they are shown to be dangerous. The Toxic Substances Control Act of 1976 was intended to regulate industrial chemicals. It applied only to newly created chemicals, however, meaning that the 60,000 chemicals already in widespread use prior to the legislation were never evaluated for safety. In fact, less than 2 percent of the 80,000 chemicals in use in the United Sates have ever been safety-tested.10
Most of us assume that a product must be safe if it is on the shelves—but that isn’t necessarily the case. The US Food and Drug Administration (FDA) exercises strict regulatory control over things we ingest, such as food, medication, and supplements; however, the rules are different for cleaning and personal care products.
Under the Federal Food, Drug, and Cosmetic Act, cosmetic products and ingredients, with the exception of color additives, do not require FDA approval before they go on the market.11 In other words, that shampoo you lather and scrub into your scalp has not been evaluated and approved for safety. Cleaning products—such as things we wipe on the surfaces of our homes or spray into the air—fall into an entirely different category. The Consumer Product Safety Commission (CPSC) is a federal agency tasked with guaranteeing the safety of household cleaners—but because the Toxic Substances Control Act prevents the safety testing of many chemicals, the CPSC is limited in its oversight.
Many consumer products contain ingredients that have never been adequately tested for safety—but most consumers wouldn’t know this because cleaning products are not required to carry a label of ingredients. What’s more, the “organic” label may not provide an extra level of safety. “When something says ‘organic’ and ‘natural,’ that doesn’t necessarily have any regulated meaning,” Engel explains. “You can’t just grab ‘organic’ and walk away feeling reassured. You have to read labels anyway. Just because it has bamboo fibers in it, that doesn’t make it pure.”
“There is a limit to what an individual consumer can do in terms of shopping our way out of the problem, and at some point policy changes need to be made,” Dr. Schettler says. “When you’re buying a product, you shouldn’t have to be a toxicologist to understand everything in it. Somebody should have already done that for you.”
Take Responsibility but Don’t Panic
It would be easy to look at the facts and panic, but such alarm is futile. Trying to avoid chemical exposure is like a fish swimming around in a fishbowl, trying not to get wet. We are all exposed—so the trick is learning to limit harmful exposures and make wise choices.
“One of the challenges here is not to scare people unnecessarily or inappropriately,” Dr. Schettler insists. He suggests taking an inventory of your personal habits as well as your home, workplace, and children’s school and then taking basic precautions.
“There are certain things that parents just intuitively do to protect their children. They don’t know that their child is going to go outside and get hit by a car, but they take precautions so that it won’t happen,” Dr. Schettler explains. He says we can use the same kind of common-sense approach to protecting ourselves from chemicals. “We have a lot of intuitive intelligence about when to take precautions and when not to worry. When it comes to chemical exposure, instead of waiting for the data there are ways to take action and reduce exposure without disrupting your life.”
Here are some simple steps you can take to reduce your exposure to potentially harmful chemicals:
• Go organic. Choose organic, fresh food whenever possible to reduce exposure to pesticides.
• Ditch the cans. Most canned food contains BPA. Choose fresh or frozen whenever possible, or look for cans that are labeled “BPA-free.”
• Use caution with plastic. Some plastics contain BPA. Check the number on the bottom of plastic containers—avoid those marked 7 because they often contain BPA. Some plastics are softened with phthalates that can leach into food. Do not put plastic in the microwave or the dishwasher, as the heat can release chemicals and cause them to leach into food.
• Clean house. Remove shoes before entering the house; dust, vacuum, and mop frequently to cut down on chemicals that can accumulate in dust.
• Use natural or homemadecleaningproducts******.** Most cleaning products are loaded with chemicals, and manufacturers are not required to disclose ingredients on the label. Read labels carefully and buy products that disclose their ingredients.
• Go fragrance-free. Artificial fragrances contain phthalates, which are known to disrupt the endocrine system.
• Use preventive pest management. Take a proactive approach to prevent indoor pest problems and avoid the use of indoor pesticides. If you have to resort to chemical pesticides, use them in forms that aren’t broadcast throughout the entire house.
• Get informed. Learn to read labels and recognize patterns in ingredients. _
- 2008–2009 President’s Cancer Panel. Reducing Environmental Cancer Risk: What We Can Do Now. US Department of Health and Human Services, National Institutes of Health, National Cancer Institute. April 2010. Available at: . Accessed December 28, 2012.
- Diamanti-Kandarakis E, Bourguignon JP, Giudice LC, et al. Endocrine-disrupting chemicals: an Endocrine Society scientific statement. Endocrine Reviews. 2009;30(4):293-342. doi: 10.1210/er.2009-0002.
- Centers for Disease Control and Prevention. Fourth National Report on Human Exposure to Environmental Chemicals, 2009. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention. Available at: . Accessed December 28, 2012.
- Hatch EE, Nelson JW, Qureshi MM, et al. Association of urinary phthalate metabolite concentrations with body mass index and waist circumference: a cross-sectional study of NHANES data, 1999-2002. Environmental Health. 2008;7(27). doi: 10.1186/1476-069X-7-27.
- James-Todd T, Stahlhut R, Meeker JD, et al. Urinary phthalate metabolite concentrations and diabetes among women in the National Health and Nutrition Examination Survey (NHANES) 2001-2008. Environmental Health Perspectives. 2012;120(9):1307-13. doi: 10.1289/ehp.1104717.
- Rubin BS. Bisphenol A: an endocrine disruptor with widespread exposure and multiple effects. Journal of Steroid Biochemistry and Molecular Biology. 2011;127(1-2):27-34. doi: 10.1016/j.jsbmb.2011.05.002.
- Ruhlen RL, Howdeshell KL, Mao J, et al. Low phytoestrogen levels in feed increase fetal serum estradiol resulting in the “fetal estrogenization syndrome” and obesity in CD-1 mice. Environmental Health Perspectives. 2008;116(3):322-28. doi: 10.1289/ehp.10448.
- Chamorro-García R, Kirchner S, Li X, et al. Bisphenol A diglycidyl ether induces adipogenic differentiation of multipotent stromal stem cells through a peroxisome proliferator–activated receptor gamma-independent mechanism. Environmental Health Perspectives. 2012;120(7):984–89. doi: 10.1289/ehp.1205063.
- Martina CA, Weiss B, Swan SH. Lifestyle behaviors associated with exposures to endocrine disruptors. NeuroToxicology. 2012;33(6):1427-33. doi: 10.1016/j.neuro.2012.05.016.
- Denison R. Ten essential elements in TSCA reform. Environmental Law Review. 2009;39:10020-28.
- Is It a Cosmetic, a Drug, or Both? (Or Is It Soap?) US Food and Drug Administration website. Available at: . Accessed December 28, 2012.
- Yucel SI, Karapinar M. Effectiveness of household natural sanitizers in the elimination of Salmonella typhimurium on rocket (Eruca sativa Miller) and spring onion (Allium cepa L.). International Journal of Food Microbiology. 2005;98(3):319-23.
- Lukasik J, Bradley ML, Scott TM, et al. Reduction of poliovirus 1, bacteriophages, Salmonella montevideo, and Escherichia coli O157:H7 on strawberries by physical and disinfectant washes. Journal of Food Protection. 2003;66(2):188-93.
National Report on Human Exposure to Environmental Chemicals
This Updated Tables, March 2018, presents nationally representative and cumulative biomonitoring data gathered from 1999-2000 through 2015-2016. It also includes all the data from each previous National Report on Human Exposure to Environmental Chemicals and each of the previous Updated Tables. The Updated Tables are represented in two separate volumes: Volume One contains data tables for chemicals measured in the general U.S. population; Volume Two contains data tables for persistent organic pollutants and pesticides measured in pooled samples and adult cigarette smokers and nonsmokers. For additional details, see the Introduction section of the Updated Tables, Volume One, March 2018.
How Do Your Products Rate?
If you are curious about what you are really slathering on your skin—your largest organ—the Environmental Working Group has done your homework for you. The group has created two searchable databases that provide safety profiles for a variety of consumer products.
EWG’s Skin Deep Cosmetics Database, ewg.org/skindeep
The Skin Deep Cosmetics Database provides safety ratings for nearly 70,000 cosmetic products, including shampoos, soaps, lotions, makeup, and more. The database provides information about the risks associated with each ingredient in a product and gives the product a letter grade from A to F.
EWG’s Guide to Healthy Cleaning, ewg.org/guides/cleaners
The Guide to Healthy Cleaning contains information on more than 2,000 household products, such as cleaning solutions, air fresheners, detergents, and more. The database lists each ingredient in a product and its corresponding health risks and then gives the overall product a letter grade from A to F.
Chemicals to Avoid
While the data continue to roll in, it may be wise to avoid some of the chemicals that have been linked to hormone disruption. According to Engel, “You don’t have that much to lose by avoiding these chemicals, and you have everything to gain”:
Lead and other heavy metals
Check for Safety
Knowledge is power. Not sure if your personal exposure to chemicals puts you at risk? Check these resources to separate fact from fiction and discern your risk level.
Toxicant and Disease Database, healthandenvironment.org/tddb
The Collaborative on Health and the Environment provides this searchable database that summarizes links between chemical contaminants and approximately 180 human diseases or conditions. Users can search the database by chemical or by disease. The evidence for the link between diseases and chemicals is classified into three categories: strong, good, and inconsistent.
The US National Library of Medicine created the TOXLINE database, which provides information regarding the biochemical, pharmacological, physiological, and toxicological effects of drugs and other chemicals. TOXLINE draws references from a variety of sources and includes more than 4 million bibliographic citations, most with abstracts.
Make Your Own
Want products with only the purest and safest ingredients? Make your own. Homemade cleaning solutions are affordable, easy to make, and often more effective than commercial products. Most recipes call for a few common household staples, such as vinegar and baking soda. In fact, vinegar is a cleaning superstar with strong antibacterial properties. Women’s Voices for the Earth (womensvoices.org) provides several recipes for cleaning solutions. Invest in a few spray bottles, mix your ingredients, and make your house sparkle—safely.