Humans are exposed to plastic every day through the use of plastic packaging. These types of exposure are not without risks, as plastics can come with dangerous chemicals. BPA, short for Bisphenol A, is a chemical used to make plastic containers with the recycling code 3 or 7 or the letter PC (polycarbonate) (Azoulay et. Al., 2019, p. 32). It is also an endocrine disruptor, which means it can disrupt hormone function. When BPA is used to make plastic containers, not all of the BPA stays on the product. Some of the BPA may leach and mix with the container’s content, especially when exposed to excess heat, affecting human health when ingested (Azoulay et. Al., 2019).
BPA first enters the human body through ingestion of contaminated food and drink in an unconjugated form (the active form of BPA). They then enter the liver and conjugates rapidly with a half-life of approximately 5.3 hours. Then, BPA is excreted through bile, urine, and sweat (Genuis et al., 2010). However, the presence of a specific enzyme in human tissues interferes with this process and cause BPA to be active again.
The β-glucuronidase enzyme is present in high concentration within many tissues, including the lung, liver, kidney, and placenta (Ginsberg & Rice, 2009). This enzyme can deconjugate BPA and thus release its active form again. Because of that, BPA can then circulate through the body and affect other organs and may result in the accumulation of BPA after exposure. BPA also has lipophilic affinity with fat, and therefore when it accumulates, it can affect ongoing metabolism (Csanady et. al., 2002).
Furthermore, when BPA are circulating through the body, it can cause endocrine disruption. BPA has estrogenic properties; it mimics the structure and function of the hormone estrogen. Because of that, it can alter the synthesis of estradiol and testosterone and interfere with receptor binding (Galloway et. al., 2010), thus causing abnormalities in reproductive organ function and even neurological impairment. BPAs in the placenta can also cause placental dysfunction, increased risk of miscarriage, and neonatal mortality (Tachibana et. al., 2007). Additionally, exposure to BPA abolishes synapse’s response to estrogen and androgen in the brain’s prefrontal cortex and hippocampus (Leranth et. al., 2008). BPA can also alter and change genetics in human. When BPA is exposed to epithelial breast or prostate cell, it alters gene expression of 170 genes and increases their vulnerability to other carcinogens, resulting in an increased risk of cancer, particularly breast and prostate cancer (Weng et. al., 2010).
BPA has adverse effects on human health. Therefore, the use of plastic containing BPA are to be avoided and the use of alternatives are recommended.
Bibliography
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