{"id":4146,"date":"2015-01-26T15:47:40","date_gmt":"2015-01-26T20:47:40","guid":{"rendered":"http:\/\/blogs.edf.org\/health\/?p=4146"},"modified":"2015-01-26T15:47:56","modified_gmt":"2015-01-26T20:47:56","slug":"evidence-mounts-on-bpas-adverse-effects-on-human-health","status":"publish","type":"post","link":"https:\/\/blogs.edf.org\/health\/2015\/01\/26\/evidence-mounts-on-bpas-adverse-effects-on-human-health\/","title":{"rendered":"Evidence mounts on BPA\u2019s adverse effects on human health"},"content":{"rendered":"

Lindsay McCormick <\/em><\/a>is a Research Analyst.<\/em><\/p>\n

Bisphenol A (BPA) is a high production volume chemical that is used to make polycarbonate plastics<\/a> and epoxy resins<\/a>.\u00a0 It is commonly found in food and beverage packaging, such as plastic bottles and the lining of food cans, as well as thermal paper receipts (see our previous blog<\/a>).\u00a0 BPA is widely-recognized as an endocrine-disrupting chemical<\/a>, meaning that it can alter the normal functioning of the body\u2019s hormonal system.\u00a0 Hundreds<\/a> of studies have been published associating BPA exposure with health effects, ranging from cancer to obesity to attention-deficit hyperactivity disorder.\u00a0 Data from the Center for Disease and Control (CDC) show that nearly all people tested have BPA in their bodies<\/a>.<\/p>\n

Despite a plethora of data, numerous calls for action (for example, see here<\/a>, here<\/a> and here<\/a>), and comprehensive regulation in France<\/a>, it does not seem that national regulation of BPA in food packaging in the U.S. will be happening any time soon.\u00a0 The official position of the U.S. Food and Drug Administration (FDA) is that, while BPA exhibits endocrine-disrupting properties at high doses, it is safe at the current levels occurring in food<\/a>.\u00a0 Although the FDA banned the use of BPA-based materials in baby bottles, sippy cups, and infant formula packaging<\/a> in 2012, FDA said it based this action on changes in the market, rather than safety concerns.<\/p>\n

In the fall of 2014, FDA completed a four-year review<\/a> of the literature, including more than 300 scientific studies, and concluded that the information does not \u201cprompt a revision of FDA\u2019s safety assessment of BPA in food packaging at this time.\u201d<\/p>\n

The European Food Safety Authority (EFSA) recently followed suit with their announcement<\/a> that BPA does not pose a health risk to consumers, including children, at current exposure levels.\u00a0 (This is in contrast to the action of several EU member states<\/a>, which have banned BPA in food contact materials for children under 3 years of age over the past few years.)<\/p>\n

Meanwhile, scientists continue to churn out studies linking low-level BPA exposure to a variety of health effects.\u00a0 In this post, we discuss several new studies. \u00a0<\/p>\n

Metabolic health<\/em><\/strong><\/p>\n

Last week, researchers from the University of Michigan, New York State Department of Health, and North Carolina State University published a study<\/a> investigating the following hypothesis: Prenatal exposure to BPA, at levels representative of actual human exposure, affect metabolic risk factors for the development of diseases such as type 2 diabetes and cardiovascular disease later in life.<\/p>\n

In order to test this hypothesis, the researchers used a unique study design, where human research was conducted alongside animal studies in sheep, rats, and mice.\u00a0 For the human portion of the study, the researchers collected blood samples from 24 mothers during the first trimester of pregnancy as well as from the umbilical cord at delivery. \u00a0They analyzed the samples for BPA levels and known risk factors for type 2 diabetes and cardiovascular disease, specifically markers of oxidative stress<\/a> and imbalances in the levels of free fatty acids<\/a> (FFAs).\u00a0 Mothers with higher levels of BPA showed greater evidence of oxidative stress and increased palmitic acid, a common fatty acid.<\/p>\n

These results were supported by the experimental animal studies, where adult sheep, rats, and mice that had been prenatally exposed to BPA at levels similar to those to which humans are currently exposed showed evidence of increased oxidative stress (in sheep and rats) and altered FFA levels (in mice).\u00a0 These experimental studies indicate the potential for prenatal BPA exposure to have long-lasting effects on metabolic health, into adulthood.<\/p>\n

Cardiovascular effects<\/em><\/strong><\/p>\n

Earlier this month, researchers from the University of Cincinnati College of Medicine published a study<\/a> linking cardiovascular effects in mice to low levels of BPA exposure.\u00a0 The researchers administered BPA to mice in their food in a manner and at doses that mimic human exposure patterns and levels.\u00a0 Female mice were dosed so as to expose their offspring from conception.\u00a0 Researchers then continued to dose these offspring after birth through adulthood. \u00a0The low end of the dose range used was comparable to estimated current levels of human oral exposure, while the high end of the dose range was near FDA\u2019s current No Observed Adverse Effect Level (i.e., the highest dose that FDA maintains yields no health effects<\/a>).<\/p>\n

The study identified several effects on markers of heart health, including decreased systolic blood pressure, structural changes in the heart, and changes in the expression of genes related to metabolic function in heart tissue.\u00a0 The response was dose-dependent for many (although not all) outcomes, and the dose-response often differed between males and females.\u00a0 In female mice only, co-exposure to BPA and isoproterenol, a drug that mimics the effects of a heart attack, increased heart muscle damage and collagen formation \u2013 an indicator of scarring \u2013 over that seen with the drug alone. \u00a0Overall, female mice exposed to BPA demonstrated more pronounced stress-induced effects than male mice.\u00a0 The authors conclude that this study adds to a body of evidence suggesting that BPA exposure may adversely affect heart health, particularly in females.<\/p>\n

A study<\/a> published last month by researchers from Seoul National University in Korea found that acute increases in systolic blood pressure in humans were associated with BPA exposure from an everyday scenario: drinking beverages from cans.\u00a0 60 participants (>60 years old) consumed the same beverage either out of glass bottles or cans; researchers then measured urinary BPA concentration, blood pressure, and heart rate variability two hours later.<\/p>\n

The researchers used a crossover study design, in which each participant came to the study site three times and consumed the same beverage in three different combinations: two bottles, two cans, or one bottle and one can.\u00a0 Urinary BPA levels were 1,600% higher and systolic blood pressure significantly increased after beverage consumption out of two cans, compared to consumption out of two bottles. \u00a0A smaller, but still statistically significant, increase in urinary BPA levels was seen in the one-can\/one-bottle scenario, although there was no significant change in blood pressure. \u00a0No change in heart rate variability was observed among the three scenarios.<\/p>\n

Developmental neurotoxicity<\/em><\/strong><\/p>\n

The University of Cincinnati study comes on the heels of research<\/a> published by the University of Calgary in Canada, which found associations between BPA exposure at low doses (comparable to or lower than current human exposure levels) and altered neurodevelopment and hyperactive behavior in zebrafish.\u00a0 The authors note that the BPA concentration used was 2-3 orders of magnitude lower than typical BPA levels found in the human placenta, levels measured in human fetal serum, and levels determined to be safe by U.S., Canadian, and EU international regulatory agencies.\u00a0 Bisphenol S (BPS), a BPA analogue that is frequently used as a theoretically \u201csafer\u201d BPA replacement in products, was also studied.<\/p>\n

The study found that exposure to BPA and BPS was associated with 180% and 240% increases in the growth of new neurons (brain cells), respectively, in the hypothalamus — a region of the brain involved in hyperactivity in humans.\u00a0 In addition, exposing zebrafish to BPA or BPS during a developmental period analogous to human gestation was associated with hyperactive behavior at a later lifestage.<\/p>\n

Zebrafish are frequently used as an animal model for human development.\u00a0 Not only do they share approximately 70%<\/a> of their genes with humans, but their organ development and function is remarkably similar to that in humans<\/a>.\u00a0 Nonetheless, extrapolating findings from animal models to humans should always be done with caution.\u00a0 Although the relevance of these effects observed in zebrafish to humans remains to be seen, the study provides evidence that biologically relevant levels of BPA \u2013 and BPS \u2013 may alter neurodevelopment.<\/p>\n

Money talks<\/em><\/strong><\/p>\n

Dr. Leonardo Trasande, an associate professor in pediatrics, environmental medicine and health policy at NYU, published an intriguing economic argument<\/a> in early 2014 for substituting BPA in food packaging with a safer alternative.\u00a0 He calculates that BPA-associated childhood obesity and adult cardiovascular disease costs the U.S. an estimated $2.98 billion annually, and that removing BPA from food packaging uses would result in a potential annual economic benefit of $1.74 billion.\u00a0 He argues that these numbers underestimate the true cost of exposure to BPA, as they do not include the potential costs from the numerous other health effects associated with BPA (such as asthma, cancer, and fertility problems).<\/p>\n

Unfortunately, finding both a safe and an effective BPA alternative has proven difficult.\u00a0 Dr. Trasande discusses the potential, and limitations, of several proposed substitutes such as oleoresin, a plant-based mixture of oil and resin, which he suggests may not be associated with adverse health effects.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Lindsay McCormick is a Research Analyst. Bisphenol A (BPA) is a high production volume chemical that is used to make polycarbonate plastics and epoxy resins.\u00a0 It is commonly found in food and beverage packaging, such as plastic bottles and the lining of food cans, as well as thermal paper receipts (see our previous blog).\u00a0 BPA …<\/p>\n","protected":false},"author":50533,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[56100,5009],"tags":[39187,91633],"coauthors":[],"class_list":["post-4146","post","type-post","status-publish","format-standard","hentry","category-emerging-science","category-health-science","tag-bisphenol-a","tag-fda"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/4146","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/users\/50533"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/comments?post=4146"}],"version-history":[{"count":0,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/4146\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/media?parent=4146"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/categories?post=4146"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/tags?post=4146"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/coauthors?post=4146"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}