Scientists have demonstrated what they are calling a causal link between environmental phthalates (toxic chemicals found in everyday consumer products like personal care, food and home care products) and the increased growth of uterine fibroids, the most common tumors among women.
What are phthalates?
Phthalates are endocrine disrupting chemicals (EDC)* that are used in numerous industrial and consumer products, especially food packaging (where they migrate into the food), personal care products (like cosmetics, soaps and hair care products including shampoos), medical supplies and household products (like plastic shower curtains). Although they are known to be toxic, they are not banned in the U.S. Phthalate chemicals have been linked in scientific studies to a variety of very serious health outcomes.**
Phthalate Chemicals and Uterine Fibroid Tumors
Up to 80% of all women may develop a fibroid tumor during their lifetime. One-quarter of these women become symptomatic with excessive and uncontrolled uterine bleeding, anemia, miscarriages, infertility and large abdominal tumors necessitating technically difficult surgeries. Additionally, uterine leiomyoma (LM) is the most common tumor in women and causes severe morbidity in 15 to 30% of reproductive-age women. (More specifically, uterine leiomyoma (LM) is the most common gynecological benign smooth muscle tumor originating from the uterine myometrium.) The new scientific study has found that phthalate chemicals in personal care products, household products and food may trigger these uterine fibroid tumors in women.
Bottom Line: The new study found women with a high exposure to certain phthalates such as DEHP (used as a plasticizer to increase the durability of products such as shower curtains, car upholstery, lunchboxes, shoes and more) and its metabolites have a high risk for developing a symptomatic fibroid tumor.
While prior epidemiological studies have consistently indicated an association between phthalate chemical exposure and uterine fibroid growth, this study explains the mechanisms behind that link–especially with regard to the phthalate chemical known as “DEHP”. The scientists discovered exposure to DEHP may activate a hormonal pathway that activates an environmentally responsive receptor (AHR) to bind to DNA and cause increased growth of fibroid tumors.
More about DEHP Phthalate Chemicals
“DEHP has been the most widely used phthalate chemical. Although there has been increased concern in the public and some regulatory restrictions in European Union countries, it is still widely used for the packaging of food and health products in the U.S. and across the world. DEHP can be gradually released from consumer products into indoor environments such as homes, schools, daycare centers, offices and cars. It settles on floors and other surfaces and can accumulate in dust and air. During pregnancy, DEHP can pass from mother to baby.
“The general public can also be exposed to DEHP through ingestion of food, drink, or dust that has come in contact with materials containing DEHP, or through inhalation of contaminated air. Individuals treated with medical products containing DEHP are at risk for exposure to high levels of DEHP.” (source)
It was proposed that endocrine-disrupting chemical (EDC) of phthalate DEHP may affect LM (uterine tumor) growth by interfering with the action of estrogen and progesterone, two steroid hormones critical for LM growth. Researchers determined the composition of the chemical mixtures based on urinary metabolite concentrations of phthalates reported in the Midlife Women’s Health Study (MWHS), which assessed the association between urinary phthalate metabolite concentrations and women’s health conditions in a prospective cohort of pre- and perimenopausal women from Baltimore and its surrounding counties. Urinary concentrations of these metabolites are measured to evaluate the exposure to DEHP. Studies have shown that DEHP and its metabolites influence steroid hormone levels and reproductive organ development and function. Recently, an association between phthalate exposure and LM (uterine tumor) growth has been established. Epidemiological studies have shown that higher urinary concentrations of phthalates, especially DEHP and its metabolites, correlate with an increase in total LM burden (uterine volume and LM size), increased risk of LM, and increased microRNA expression associated with cellular processes favoring LM growth.
Overall, the phthalate metabolite mixture was positively associated with prior LMs diagnoses, such that 10% increases in urinary concentrations of all nine metabolites were associated with 6.0% higher risk of prior LMs diagnosis.” (source)
The findings indicated the phthalate chemical metabolite DEHP is a particularly high-risk factor for LM (uterine tumor) growth. The scientists demonstrated that exposure to mixtures of phthalate metabolites or the single compound–a major DEHP metabolite–can increase LM cell survival and risk of development of LMs (uterine tumors) or induction of their growth.
Read the ingredients labels of all personal care products (especially feminine care products) as well as home care products. Choose products that specifically say they are “Phthalate-Free” and avoid all products that list “DEHP” in the ingredients. Additionally, greatly minimize fast food and highly-processed foods sold in plastic containers–both of which have been found in laboratory studies to contain high levels of phthalate chemicals.
*“Endocrine-disrupting chemicals (EDCs) are defined as exogenous chemicals or a mixture of chemicals that interfere with the endocrine system and alter hormone activity. EDCs were once thought to function by manipulating nuclear hormone receptors, such as estrogen receptors, androgen receptors, progesterone receptors, thyroid receptors, and retinoid receptors; however, research has since revealed that the mechanisms of EDC effects are much broader than initially recognized. EDCs have been shown to affect the functions of nonsteroid receptors (e.g., neurotransmitter receptors) and other nuclear receptors (e.g., aryl hydrocarbon receptor [AHR]), and interfere with enzymatic pathways involved in steroid biosynthesis and metabolism in the endocrine and reproductive systems.” (source)
** See our previous posts of scientific studies findings on phthalates and serious health outcomes:
Journal Reference: Takashi Iizuka, et al. Mono-(2-ethyl-5-hydroxyhexyl) phthalate promotes uterine leiomyoma cell survival through tryptophan-kynurenine-AHR pathway activation, Proceedings of the National Academy of Sciences (PNAS), November 14, 2022, 119 (47) e2208886119. https://doi.org/10.1073/pnas.2208886119