(Continued from Part 1)
The endocrine system is a series of glands that produce and secrete hormones that the body uses for a wide range of functions. This system involves the brain, thyroid, kidneys, pancreas and gonads.
Endocrine disruption is a phenomenon that occurs when a man-made or natural compound interferes with normal hormone function in humans or animals, and changes the way the body communicates and responds to its environment.
Around 1000 chemicals in use worldwide (in many types of products) are classified as endocrine-disrupting chemicals (EDCs) due to their ability to mimic or block the action of natural hormones and interfere with development and function.
EDCs have been linked to adverse impacts on both the endocrine and nervous systems (which are intimately intertwined), and have been known to alter important animal behaviours by modulating serotonin and dopamine in the body (neurotransmitters which regulate many functions including mood, sleep and cognition), as well as other neurotransmitter pathways.
The brain is highly vulnerable to EDCs.
Recently, public concern has been focused on the effects of EDCs on brain function, driven by an increase in neuropsychiatric disorders, including autism, ADHD, as well as learning disabilities and aggressiveness, with several lines of evidence also suggesting that exposure to EDCs is associated with depression.
Increasing evidence indicates that EDCs may also affect our mental health by their influence on cortisol (stress hormone) in the body. An imbalance of cortisol can lead to many health problems, including depression, anxiety, irritability and mental confusion.
The World Health Organization, the United Nations, and the US National Toxicology Program are just a few of the leading agencies concluding that EDCs may cause a variety of neuroendocrine dysfunction that negatively affect the brain and behaviour.
Phthalates are a group of chemicals that act as binding agents and plasticizers. No doubt you’ve heard of them - they are everywhere, used in everything from household cleaners to food and food packaging, fragrance, cosmetics and personal care products.
The potential dangers of phthalates have been highlighted publicly since 2003, when the USA CDC (Centre for Disease Control) warned against their potential danger to human health, and recommended phthalates be studied more closely to scrutinise their health effects.
Phthalates are anti-androgenic (they displace testosterone). Research suggests that the anti-androgenic action of phthalates could be one possible mechanism underlying anxiety-like like behaviour after phthalate exposure seen in animal studies. In humans, typical symptoms of low testosterone in both men and women include depression and/or anxiety.
Data from these studies have shown that HPG and HPA axis activity in the endocrine system, as well as anxiety and stress responses, are changed by exposure to phthalates. Symptoms of HPG/HPA axis dysfunction typically include difficulty handling or managing stress, dysregulated emotions, exhaustion and anxiety.
Several studies have demonstrated that phthalate exposure during all major developmental stages of life significantly disrupts the function of the brain’s hippocampal region and structural plasticity following exposure to phthalates. Perinatal exposure to phthalates (which can readily cross the placenta) has been demonstrated in lab studies to have a marked effect on the cortical regions of the developing brain (involved in executive function and the pathology of many neuropsychiatric disorders), suggesting that perinatal exposure could have serious impact for the development of mental health disorders.
Research suggests that babies exposed to phthalates in utero to phthalates have a greater chance of adverse cognitive and behavioural outcomes, including lower IQ, and problems with attention, hyperactivity, and poorer social communication.
In our final post on this topic, we will continue the discussion by looking at the body system most impacted by exposure to these fragrance chemicals.