In August 2018, a provocative study published in Environmental Research suggested that hair products commonly used by African American women and children may contain multiple chemicals associated with endocrine disruption and asthma.1 A team of researchers used gas chromatography/mass spectrometry to test 18 hair products, including hot oil treatment, anti-frizz polish, leave-in conditioner, root stimulator, hair lotion, and relaxer. The products tested contained 45 endocrine-disrupting or asthma-associated chemicals, including cyclosiloxanes, parabens, and the fragrance marker diethyl phthalate (DEP). Hair relaxers for children contained five chemicals regulated by California’s Proposition 65 or prohibited by European Union cosmetics regulation, and the chemicals studied were generally not listed on the product label. Root stimulators, hair lotions, and relaxers frequently contained nonylphenols, parabens, and fragrances; anti-frizz products contained cyclosiloxanes.1
These are unfortunately only a few in a long list of synthetic chemicals we may encounter, sometimes daily, over the course of our lives. The US Centers for Disease Control and Prevention began measuring human exposure to chemicals in 1976. These “biomonitoring” studies are ongoing and continue to find a range of toxins in subjects’ blood and urine—substances like dichlorodiphenyltrichloroethane (DDT) and glyphosate from pesticides, bisphenol-A (BPA) from food containers, plastics, and cash register receipts,2 and phthalates in toys and shampoos3 …. the list goes on.
Scientists have only just begun to understand the complex nature of volatile organic compounds (VOCs), and the EPA has regulated only a few despite their associated health effects, which may include headache, damage to the liver, kidneys, and nervous system, visual disorders, memory impairment, and cancer.4
In the following video, IFM educator Robert Rountree, MD, explains how he advises parents on toxic exposures in children:
Carpets & Home Furnishings
A wide variety of endocrine-disrupting chemicals have been known to gather into indoor dust and accumulate on carpets, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), phthalates, pyrethroids, DDT, and chlordanes.5,6 A 2010 study analyzed indoor dust samples from household cleaner bags provided by 10 apartments and one community hall in Davis, California, and all samples contained several toxins.7 Di-(2-ethylhexyl)phthalate was the most abundant chemical, but PBDEs were also found at high concentrations. Some samples even showed concentrations of PCBs at levels considered to be of concern for health, in spite of the fact that PCB use has been banned since 1979.7
Small children may even be at greater risk than adults to the adverse health effects linked to indoor contaminants because of their small body mass, limited ability to detoxify and excrete xenobiotic toxic chemicals, rapid growth, activities close to the floor, tendency for inadvertent ingestion of non-food items, and hand-to-mouth behavior.6 Children also spend much of their time sleeping, and studies suggest that they may be exposed to elevated concentrations of chemicals released from some crib mattresses.8 A 2014 study examined the emission rates of VOCs in a collection of 20 new and used crib mattresses, and found that all mattresses emitted VOCs, but that values of total VOCs were higher in new mattresses compared to used. A variety of VOCs were identified, with polyurethane foam releasing a greater diversity of VOCs compared to polyester foam.8
Some children and their families may also have been exposed to chemical flame retardants in synthetic materials like furniture and/or rugs or carpet padding, which have been linked to cancer, hormone disruption, and other health effects.9 A 2018 study suggests that these chemicals, called PBDEs, have been shown to disrupt thyroid hormone (TH) homeostasis through multiple mechanisms, including inhibition of enzymes that regulate intracellular levels of TH such as sulfotransferases.9 A 2017 systemic review and meta-analysis found that there was sufficient evidence to support an association between developmental PBDE exposure and reduced IQ.10 In 2006, a case study published by Fischer et al found that in a California family of four, levels of PBDEs in the children’s blood were two- to five-fold higher than those of their parents.11
Personal Care Products
The human risk of exposure to xenobiotic toxic substances in personal care products has been acknowledged and studied for quite some time, and some are composed of endocrine-disrupting and asthma-associated chemicals.1 A 2018 study of 2,106 healthy pregnant women from the US, followed through delivery, found that reductions in umbilical circumference and bone lengths may be a sensitive marker of intrauterine endocrine-disrupting chemical exposure, particularly for poly-and-perfluorinated alkyl substances.12
Certain phthalates, ubiquitous xenobiotics found in many plastic products, cosmetics, and personal care products, have shown endocrine-disrupting and anti-androgenic properties in human studies.13 According to the Center for Disease Control, 2015 biomonitoring surveys of the United States population consistently detect phthalate metabolites in greater than 90% of those surveyed. Vulnerable populations, such as women of reproductive age, infants, and young children, as well as racial and ethnic minorities, may be more exposed to phthalates than persons of other demographic strata.12 Several studies have suggested potential neurodevelopmental outcomes in children related to cognitive and behavioral development.13
In a 2017 study of a diverse population of urban mother-child pairs, maternal exposure to phthalates in late pregnancy was associated with the female child’s mental and psychomotor development.13 Girls of mothers with higher urinary concentrations of metabolites of dibutyl phthalates (MCPP) had lower mental development index, MDI, and scores on the Bayley Scales of Infant Development II.13 Similarly, a 2010 study examined a multiethnic prenatal population in New York City between 1998 and 2002; third-trimester maternal urine was analyzed for phthalate metabolites, and the children were assessed for cognitive and behavioral development between the ages of four and nine years old.14 Behavioral domains adversely associated with exposure to low-molecular-weight phthalates were commonly found to be affected in children clinically diagnosed with conduct or attention deficit hyperactivity disorders (ADHD).14
It’s important to note that not all products labeled “natural” are harmless to the human body. In 2015, a study in Environmental Sciences Europe identified over 1,000 natural substances—mainly of herbal origin—that appear in the International Nomenclature of Cosmetics Ingredients (INCI), out of which 38% are classified as hazardous to human health.15 Fifty-three natural substances in the INCI list are classified as carcinogens, mutagens, and substances toxic to reproduction. Examples of chemicals that pose a risk to human health are cyanogenic glucosides, different toxic alkaloids (such as strychnine, atropine, and aconitine), phytoestrogens such as sterols and isoflavones, terpenes and terpenoids (as in many oils and fats), quinones, and peroxides.16
It’s clear that humans are exposed to literally hundreds of chemicals, even prior to birth, many of which have the potential to negatively affect health. As a Functional Medicine practitioner, how do you recognize toxicity in your patients?
Understanding toxicity and taking practical steps to improve biotransformation are essential and critical pieces in any integrative approach to a patient’s health and well-being. Learn more in IFM’s Biotransformation ( Formerly Detox) Advanced Practice Module (APM), where expert faculty will review the foundational biochemistry and genetics of biotransformation pathways, connect organ system dysfunctions to potential toxic exposures, and detail the available laboratory evaluations useful in working up a toxin-exposed patient. Once these important clinical connections are made, the team will detail specific treatment approaches. This program uses a case-based, integrated approach to deliver the tools necessary for clinicians to diagnose and treat the toxic component of their patients’ total health pictures.
- Helm JS, Nishioka M, Brody JG, Rudel RA, Dodson RE. Measurement of endocrine disrupting and asthma-associated chemicals in hair products used by Black women. Environ Res. 2018;165:448-458. doi:10.1016/j.envres.2018.03.030.
- Lee C, Kim CH, Kim S, Cho SH. Simultaneous determination of bisphenol A and estrogens in hair samples by liquid chromatography-electrospray tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci. 2017;1058:8-13. doi:10.1016/j.jchromb.2017.05.007.
- US Food & Drug Administration. Phthalates. https://www.fda.gov/cosmetics/productsingredients/ingredients/ucm128250.htm Updated December 5, 2013. Accessed August 12, 2018.
- US Environmental Protection Agency. Volatile organic compounds’ impact on indoor air quality. https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality. Updated November 6, 2017. Accessed August 12, 2018.
- Paustenbach DJ, Finley BL, Long TF. The critical role of house dust in understanding the hazards posed by contaminated soils. Int J Toxicol. 1997;16(4-5):339-362. doi:10.1080/109158197227008.
- Roberts JW, Ott WR. Exposure to pollutants from house dust. In: Ott WR, Steinemann AC, Wallace LA, eds. Exposure Analysis. Boca Raton, FL: CRC Press; 2006:319-346. doi:10.1201/9781420012637.pt5.
- Hwang HM, Park EK, Young TM, Hammock BD. Occurrence of endocrine-disrupting chemicals in indoor dust. Sci Total Environ. 2008;404(1):26-35. doi:10.1016/j.scitotenv.2008.05.031.
- Boor BE, Järnström H, Novoselac A, Xu Y. Infant exposure to emissions of volatile organic compounds from crib mattresses. Environ Sci Technol. 2014;48(6):3541-3549. doi:10.1021/es405625q.
- Leonetti CP, Butt CM, Stapleton HM. Disruption of thyroid hormone sulfotransferase activity by brominated flame retardant chemicals in the human choricocarcinoma placenta cell line, BeWo. Chemosphere. 2018;197:81-88. doi:10.1016/j.chemosphere.2017.12.172.
- Lam J, Lanphear BP, Bellinger D, et al. Developmental PBDE exposure and IQ/ADHD in childhood: a systematic review and meta-analysis. Environ Health Perspect. 2017;125(8):086001. doi:10.1289/EHP1632.
- Fischer D, Hooper K, Athanasiadou M, Athanassiadis I, Bergman A. Children show highest levels of polybrominated diphenyl ethers in a California family of four: a case study. Environ Health Perspect. 2006;114(10):1581-1584. doi:10.1289/ehp.8554.
- Buck Louis GM, Zhai S, Smarr MM, et al. Endocrine disruptors and neonatal anthropometry, NICHD Fetal Growth Studies – Singletons. Environ Int. 2018;119:515-526. doi:10.1016/j.envint.2018.07.024.
- Doherty BT, Engel SM, Buckley JP, Silva MJ, Calafat AM, Wolff MS. Prenatal phthalate biomarker concentrations and performance on the Bayley Scales of Infant Development-II in a population of young urban children. Environ Res. 2017;152:51-58. doi:10.1016/j.envres.2016.09.021.
- Engel SM, Miodovnik A, Canfield RL, et al. Prenatal phthalate exposure is associated with childhood behavior and executive functioning. Environ Health Perspect. 2010;118(4):565-571. doi:10.1289/ehp.0901470.
- Klaschka U. Naturally toxic: natural substances used in personal care products. Environ Sci Eur. 2015;27:1. doi:10.1186/s12302-014-0033-2.
- Bucheli TD, Strobel BW, Hansen HCB. Personal care products are only one of many exposure routes of natural toxic substances to humans and the environment. Cosmetics. 2018;5(1):10. doi:10.3390/cosmetics5010010.