Bisphenol A (BPA) and Bisphenol S (BPS) are chemicals found in many consumer products. This article explores their nature, how they interact with the human body, and the potential health effects linked to their exposure. Understanding these compounds can help in making informed choices about everyday products and overall well-being.
Understanding BPA and BPS
Bisphenol A (BPA) is an industrial chemical widely used since the 1960s, primarily in the production of polycarbonate plastics and epoxy resins. Polycarbonate plastics are hard and clear, appearing in items such as water bottles, eyewear, and food storage containers. Epoxy resins are used to coat the inside of metal food cans, bottle tops, and water supply pipes to prevent corrosion and extend food freshness.
Bisphenol S (BPS) is a related chemical, part of the broader bisphenol family, and shares a similar molecular structure to BPA. It has increasingly been used as a substitute for BPA, particularly in thermal paper receipts and some can linings. Human exposure to both BPA and BPS primarily occurs through diet, as these chemicals can leach from product linings and containers into food and beverages. Skin contact, such as handling thermal paper receipts, and exposure to indoor dust are also recognized routes of exposure.
How BPA and BPS Interact with the Body
BPA and BPS are endocrine-disrupting chemicals (EDCs). They can interfere with the body’s natural hormone system, particularly by mimicking or interfering with estrogen. Estrogen receptors play a central role in various physiological processes, especially in the female reproductive system.
These chemicals can bind to estrogen receptors, potentially altering gene transcription and disrupting normal hormonal signaling. This interference can occur even at very low levels of exposure, often detected in human blood and urine. Most individuals have detectable levels of these chemicals in their bodies, including fetuses and infants through placental transfer and breast milk.
Documented Health Effects
Research into the health effects of BPA and BPS has linked exposure to a range of potential impacts on various bodily systems. These compounds are suspected to affect reproductive health, developmental processes, metabolic regulation, neurological function, and may even be associated with hormone-sensitive cancers.
Reproductive Health
Studies indicate that bisphenols can alter reproductive development and function. Animal studies have shown that BPA exposure can impair folliculogenesis and affect the release of hormones like FSH and LH. In male animals, developmental exposure to bisphenols has been linked to changes in prostate development and altered reproductive success.
Developmental Effects
Developmental effects are a significant area of concern, especially given that fetuses and young children may be more vulnerable to chemical exposures. Prenatal exposure to BPA has been associated with potential neurological delays and changes in brain structure and function in animal models. Some human studies also suggest a link between prenatal BPA exposure and behavioral issues in childhood, such as wheezing and aggressive behavior.
Metabolic Disorders
Metabolic disorders like obesity, diabetes, and cardiovascular issues have also been linked to bisphenol exposure. BPA has been shown to disrupt cardiovascular physiology and is associated with increased body mass index. Studies in animals indicate that BPA exposure can lead to insulin resistance.
Neurological Effects
Neurological effects extend beyond developmental impacts, with research suggesting potential influences on brain development, behavior, and cognitive function. Both BPA and BPS have been shown to influence hypothalamic development, a brain region involved in many bodily functions. Animal studies suggest that exposure to these chemicals can lead to altered maternal care behavior and enhanced anxiety-like and depressive states in offspring.
Hormone-Sensitive Cancers
The potential link between bisphenols and hormone-sensitive cancers, such as breast and prostate cancers, is an ongoing area of research. Low doses of BPA, comparable to those found in human tissues, have been observed to stimulate the proliferation of both estrogen receptor-positive and negative breast cancer cells in laboratory settings. While more research is needed to fully understand these associations in humans, the ability of bisphenols to interfere with hormone signaling raises concerns about their potential role in cancer development.
Reducing Your Exposure
Minimizing exposure to BPA and BPS involves making conscious choices about consumer products and food handling practices. Since dietary intake is a primary route of exposure, opting for fresh or frozen foods over canned alternatives can help reduce chemical leaching from can linings. If canned foods are consumed, rinsing them thoroughly may help lower the levels of bisphenols.
Using alternative materials for food and beverage storage is another strategy. Choosing containers made of glass, stainless steel, or ceramic for food and drinks, especially when heating, can limit exposure. Avoiding microwaving plastics is also recommended, as heat can increase the leaching of bisphenols into food.
Being mindful of thermal paper receipts is also beneficial, as they often contain BPA or BPS. Some suggest refusing receipts or wearing gloves if handling them frequently, as the chemicals can transfer to skin. When purchasing products, looking for “BPA-free” labels can be a start, although some “BPA-free” products may use other bisphenols like BPS, which also raise health concerns.