The growing public interest in the materials that make up our everyday lives has brought the spotlight onto synthetic fibers like polyester. As a ubiquitous material, questions have emerged regarding its potential to act as an endocrine disruptor, substances that can interfere with the body’s delicate hormonal balance. Understanding this concern involves examining what these disruptors are, the composition of polyester, and how scientific research addresses these potential connections.
Understanding Endocrine Disruptors
Endocrine disruptors (EDCs) are chemicals that can interfere with the body’s intricate hormonal system. This system relies on hormones to regulate numerous bodily functions, including growth, metabolism, reproduction, and mood. EDCs can exert their effects in several ways, such as mimicking natural hormones, blocking hormone receptors on cells, or altering the production, transport, or breakdown of hormones.
Exposure to EDCs is a health concern because they can impact various physiological processes. These substances have been linked to a range of potential health issues, including developmental, reproductive, neurological, and immune system problems. Fetuses and breastfeeding infants are particularly vulnerable to EDC exposure due to their rapid development stages. EDCs can be found in a wide array of everyday products, from plastics and cosmetics to textiles and food sources, entering the body through ingestion, inhalation, or skin contact.
Polyester: Composition and Common Uses
Polyester is a synthetic fiber composed of polyethylene terephthalate (PET). This polymer forms through a chemical reaction involving ethylene glycol and terephthalic acid, creating long polymer chains. The process often utilizes a catalyst like antimony trioxide. The resulting PET is then processed into fibers, films, or molded products.
Polyester is widely used due to its durability, affordability, and versatility. It accounts for a significant portion of global fiber production, with over 60% of PET production dedicated to synthetic fibers. Beyond clothing, polyester is also used in various applications such as packaging, including plastic bottles, and industrial materials. Its properties, including resistance to wrinkles and shrinkage, contribute to its widespread adoption in many consumer goods.
Potential Mechanisms of Endocrine Disruption from Polyester
While the base PET polymer of polyester is generally considered inert, the manufacturing process and subsequent treatments can introduce chemicals with potential endocrine-disrupting properties. Chemical additives used during polyester production, finishing, and dyeing are a concern. These include plasticizers like phthalates, used to enhance flexibility and durability, and flame retardants added to meet safety standards. Bisphenol A (BPA), a known synthetic estrogen, has also been found in some polyester-spandex apparel.
Another mechanism involves residual monomers or catalysts from the manufacturing process. Antimony compounds, frequently used as catalysts in PET production, can be present in the final fabric and have shown estrogenic responses in laboratory studies. Dyes and colorants may also contain chemicals that could leach out. Furthermore, polyester clothing sheds tiny plastic fibers, known as microplastics, during washing and wearing. These microplastics can carry adsorbed EDCs from the environment or release chemicals embedded within them, potentially entering the body through skin contact, inhalation, or ingestion.
Scientific Research on Polyester and Endocrine Health
Research on polyester and endocrine health focuses on the leaching of chemical additives and the impact of microplastics. Studies identify various chemicals in polyester fabrics, such as BPA, phthalates, and antimony, which are known or suspected EDCs. Research indicates that these chemicals can migrate from the fabric to the skin, especially under conditions of sweat and friction, potentially leading to absorption. Some studies have detected BPA levels in polyester-spandex apparel exceeding safety limits, with concerns about skin absorption. Phthalates, commonly found in synthetic fabrics, have been linked to hormonal imbalances and reproductive issues.
The base PET polymer itself has not been shown to strongly activate estrogen or androgen receptors in laboratory tests. However, the presence of various additives within polyester and the shedding of microplastics raise ongoing questions. Microplastics can act as carriers for EDCs, and studies find them in human blood, semen, and placental tissue. While the direct impact of microplastics and their associated chemicals from textiles on human endocrine disruption is an evolving area of research, animal studies suggest potential effects on hormone systems and reproductive function. Some older studies have also explored a direct link between polyester and reproductive health, suggesting potential effects on reproductive function, though further comprehensive human studies are needed.
Consumer Considerations for Polyester Products
Given the ongoing research into polyester and its potential chemical exposures, consumers can consider several practices to minimize risks. Washing polyester garments less frequently reduces the shedding of microplastics into waterways. Using colder water temperatures and shorter cycles also decreases microfiber release, as hot water and vigorous agitation causes more fibers to break off. Air-drying clothes instead of using a dryer further reduces fiber breakdown and extends garment lifespan.
Using microfiber-catching laundry devices, such as specialized bags or balls, can help trap microfibers before they enter wastewater. Spot cleaning garments when possible, instead of full washes, also contributes to reducing chemical and microplastic release. Choosing natural fibers like cotton, wool, or linen for certain items may offer an alternative for those seeking to reduce exposure to synthetic materials and their associated additives.