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    Both BPA and BPA-Free Alternative, Bisphenol S, Negatively Affect Fetal Brain Development

    BPA-free Water BottleIf you are concerned about the effects of chemicals such as BPA in plastics, you may want to avoid BPA-free products that contain BPS as well. A new study from researchers at the University of Calgary in Alberta, Canada have found that both BPA and BPS can cause alterations in brain development that can lead to hyperactivity.

    Bisphenol A, or BPA, is a synthetic compound used to make certain plastics and epoxy resins. The addition of BPA results in plastic that is clear and durable. The chemical is found in common consumer goods such as baby and water bottles, sports equipment, and CDs and DVDs. Bisphenol A is also used as a coating inside many food and beverage cans, inside water pipes, and on thermal print receipts.

    After public concerns about the negative health effects of BPA, many manufacturers replaced the chemical with an alternative called BPS. Bisphenol S, or BPS, is an organic compound that functions similarly to BPA. Touted as a safer alternative, BPS gained greater use as a plasticizing agent following the widespread bans on the use of BPA.

    Explains lead author Deborah Kurrasch of the Cumming School of Medicine at the University of Calgary, “A lot of the alternative chemicals have not been adequately tested because they don’t have to be. A compound is considered safe (by the Food and Drug Administration) until proven otherwise.”

    However, the present study concludes that BPS may cause more health problems than BPA. BPA is a known endocrine disrupter. BPS exhibits similar endocrine-disruptive activity. Exposure to endocrine disrupters during prenatal development may increase the risk of obesity, cancer, and negative behavior such as aggression and hyperactivity.

    Using an animal model involving zebrafish, the researchers exposed embryonic zebrafish to very low-dose BPA and bisphenol S. The researchers used zebrafish because approximately 80 percent of the genes found in human have a counterpart in the fish, which have very similar developmental processes as humans. The doses used were comparable to concentrations found in Alberta’s Oldman River, a waterway affecting two urban centers. The fish were exposed to the chemicals during a developmental period comparable to that of the second trimester in humans.

    Explains Kurrasch, “We wanted to use a dose that was found in a natural waterway and that people would get in their drinking water. Waste-water treatment plants do not filter out BPA so this is presumably what is coming into people’s houses.”

    The researchers found that exposure to BPA and BPS altered the timing and rate of new neurons developing in the hypothalamus, a brain region involved in regulating hunger, mood, hormones, body temperature, heart rate, and other key physiological functions. Embryos exposed to BPA experienced a180 percent increase in the number of new brain cells produced compared with control embryos, and embryos exposed to BPS experienced a 240 percent increase. Exposed fish also created too many neurons too soon and too few later, which can disrupt the formation of connections in neural circuitry and induce adverse behaviors such as hyperactivity.

    Comments Kurrasch, “I was actually very surprised at our results. This was a very, very, very low dose, so I didn’t think using a dose this low could have any effect,” adding, “We used a dose that is lower than what developing babies have naturally and we found that brain development is perturbed [in the fish].”

    Despite exposure to extremely low doses of BPA and BPS, exposed fish in the study demonstrated greater hyperactivity later in life.

    In other words, both BPA and the alternative BPS may negatively affect fetal brain development.

    Says Hamid Habibi, a professor of environmental toxicology and comparative endocrinology in the Faculty of Science, “Finding the mechanism linking low doses of BPA to adverse brain development and hyperactivity is almost like finding a smoking gun.”

    Adds George Bittner, a professor of neurobiology and pharmacology at the University of Texas at Austin, “I think this is a very important paper that gives evidence that compounds like BPA and BPS have very detectable effects at low dosages on developing vertebrates.”

    The current study adds to the growing evidence linking bisphenols to negative health effects including the recommendation that women avoid exposure to chemicals like BPA and BPS during pregnancy. However, additional research such as the effects of exposure to BPA and BPS on mice is needed to draw appropriate conclusions about human health.

    References

    Bisphenol A: http://en.wikipedia.org/wiki/Bisphenol_A
    Bisphenol S: http://en.wikipedia.org/wiki/Bisphenol_S
    BPA alternative disrupts normal brain-cell growth, is tied to hyperactivity, study says: http://www.washingtonpost.com/national/health-science/bpa-alternative-disrupts-normal-brain-cell-growth-is-tied-to-hyperactivity-study-says/2015/01/12/a9ecc37e-9a7e-11e4-a7ee-526210d665b4_story.html
    BPA and BPA-free alternative, bisphenol S, linked to disruptions in brain development in zebrafish study: http://www.oregonlive.com/pacific-northwest-news/index.ssf/2015/01/bpa_alternative_bisphenol_s.html
    BPA and BPS both lead to hyperactivity in zebrafish, study finds: http://www.cbc.ca/news/canada/calgary/bpa-and-bps-both-lead-to-hyperactivity-in-zebrafish-study-finds-1.2898738
    Low-dose exposure to bisphenol A and replacement bisphenol S induces precocious hypothalamic neurogenesis in embryonic zebrafish: http://www.pnas.org/content/early/2015/01/07/1417731112

    Image Credits

    BPA-free Water Bottle © 2012 Heather Johnson

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