Biochemical Effects of Endocrine Disrupting Molecules
Increased education and awareness of the public about the dangers of the exposure to certain synthetic or man-made substances has led to a high rise in the consumer demand for organic and non-toxic goods.
The Endocrine Society first reported in 2009 that Endocrine Disruptors (EDs) pose a serious threat to public health. A survey conducted by the Environmental Working Group in 2004 found that the average adult is exposed to 126 individual chemicals and uses an average of nine personal care products per day. Yikes!
In cosmetics, most companies utilize EDs to function as, enhancers for deeper penetration of the molecules into the skin, preservatives to prevent microbial and fungal growth, stabilizers to prevent oxidation, and man-made fragrances to cover up the smell of the above chemicals. Some companies even use color additives to make the product visually appealing.
Biochemical Effects of EDs
EDs are defined as chemicals that disrupt the body’s hormonal metabolism, action, and homeostasis, and stem from a broad range of chemicals. The commonly investigated types of EDs in the literature include synthetic solvents and lubricants, pesticides, preservatives, fragrances, and plasticizers. Long-term and daily exposure to EDs may promote mutagenic developmental effects on systems of the endocrine, reproductive, neurological, and immune, to name a few.
The long shelf-life of some of these compounds is unfavorable in nature; bioaccumulation of these chemicals could cause long-term irreversible damage to the internal organs since your body may be chemically incapable of degrading or excreting the ED in a timely manner. In other cases, chemical breakdown of the ED yields a metabolite that is more toxic than the parent compound.
Studies conducted in both animal models and human clinical trials reveal that exposure to EDs results in misregulation in the metabolism of hormones of the reproductive system like estrogen and testosterone, for example, and leads to increased ovarian, breast, prostate, and testicular cancer, premature birth, and reproductive issues in men (low sperm count) and women (endometriosis) and developmental deficiencies in the reproductive organs of children. In the nervous system, chronic exposure to EDs attribute to autism, attention deficit disorders, and other neurobehavioral and learning disorders.
Exposure Through the Skin
The kinds of exposure to EDs are widespread and one mode of entry into the body includes absorption through the skin when using cosmetics or beauty products that contain these unfriendly synthetic chemicals. This method of entry into the body is noteworthy because the skin is the largest organ in the human body; including the hair and nails, and accounts for about fifteen percent of your body’s total weight.
The skin protects us from infectious microbes, helps regulate the temperature of the body, and allows for the sensation of touch and nociception. This organ is a multi-layered system and comprised of specialized cells and glands and each layer contains a large amount of lipid-containing tissue. This chemical feature is ideal for the absorption of small organic based compounds into the body and, unfortunately, lipid solubility is often a characteristic feature of industrial EDs.
In cosmetics, parabens are the most common class of preservatives found in moisturizers, shampoos, and soaps and function as antibacterial and antifungal agents. Chemically, parabens are substituted esters of p-hydroxybenzoic acid; in particular, butyl and benzyl paraben derivatives are more toxic than the lower hydrocarbon chain derivatives.
Parabens are repeatedly demonstrated in the literature to function as estrogen mimics and thereby disrupt the natural pathways that regulate the metabolism of estrogen or bind to the molecule. These compounds exert negative actions in the body by disrupting the biosynthesis and intracellular signaling pathways of estrogen in the body and competes with the binding of estrogen to native receptors altering the expression levels of estrogen proteins. Increased rates of breast, cervicall, ovarian, and even melanoma in women are linked to the exposure of parabens.
In addition to causing reproductive issues in women, parabens are also known to interfere with reproduction in males and lead to lower levels of testosterone production and cause damage to spermatogenesis. Findings from animal model studies indicate this issue is extended further in the unborn offspring and fetal exposure to butylparaben led to a reduction in the size of the testis, seminal vesicles, and prostate glands.
Phthalates are found in polymer-based materials, like plastics, and serve a chemical role to increase the flexibility of the plastic and prevent breakage. As is the case with the parabens, the higher carbon-containing compounds ester derivatives are more toxic and disruptive than the smaller carbon-based molecules.
These compounds are cited across the literature as disruptors of the male and female reproductive systems of. In male animal models, the exposure to phthalates leads to abnormal testicular development and function and reduced number and quality of sperm. On the other end of the spectrum, phthalates attribute to premature breast growth in girls and endometriosis in older women.
Polychlorinated (PCBs) and brominated (PBBs) substituted aromatic chemicals that accumulate in adipose tissue and generally found in industrial solvents and lubricants. These compounds are long-lasting organic pollutants with high lipid solubility and are particularly nasty because they can function as alkylating agents. Alkylating agents may act as mutagenic substances and alter the biochemical properties of DNA, proteins, and lipids.
Halogens are established radical initiating and propagating molecules and inducers of oxidative stress and in the present as endocrine disruptors. In the case of unsaturated lipids and in the presence of oxygen, for example, free radicals may initiate homolytic cleavage of a C-H bond resulting in a hydrogen atom and a single electron abstraction and subsequent oxidation or peroxidation of the parent molecule.
The disruptive effects of PCBs and PPBs in males are reduced sperm production and delayed onset of puberty and are linked to reduced levels of testosterone, infertility, and increased risk of testicular cancer. For developing females, these compounds produce just as many problems in the reproductive system and studies report early puberty, stimulation of the endometrium, and notably even a reduction in the weight of the vagina.
Chemically, phenols consist of a benzyl group bonded to a hydroxyl group and this moiety is redox active. Phenols like the essential amino acid tyrosine function, for instance, as important co-factors at the active sites of transition metal enzymes and facilitate redox, acid-base, and metal-binding reactions that are critical to life. The importance of these compounds in maintaining homeostasis and in particular redox homeostasis cannot be stressed enough.
EDs often contain phenolic substituents and this structural feature allows for the interaction of the ED with various steroid receptor hormones. Bisphenol A (BPA) is an example of a phenol-containing endocrine disrupting compound found in plastics, cosmetic packages, cans, and resins.
Studies in both animal and human models show BPA acts as an estrogen mimic and effects the development of male and females in the womb. Malformation of the breasts, mammary glands, and uterine lining are reported in females and prostate, urethra, and testis of males.
Given the prevalence of EDs in cosmetic formulas, food, and the environment, consumers must be aware of what chemicals go on or in their body since the exposure and accumulation of EDs and can be detrimental to the health of themselves and, more importantly, their children. In an ever-increasing world of industrialization and man-made substances, consumers are constantly exposed to new and existing EDs.
Understanding the physical source of where EDs come from and the various methods of exposure are critical to protecting your hormonal health, especially when given the chance to consume products that are free of these toxic contaminants.