Bisphenol A: Exposure in the
Environment as it Relates to
Health
Candace Waynick, RD LD
October 24, 2011
NUTN 507: Seminar
Objectives
 Discuss the synthetic and legal history of
Bisphenol A (BPA)
 Describe uses of BPA and BPA containing
products
 Discuss harmful effects of exposure to BPA
and controversial methods of testing
 Describe the role of dietitians to minimize
public health risks associated with BPA
Synthetic History
 2 phenol compounds and 1 acetone
 Recognized for estrogenic properties in
1930’s by Edward Charles Dodd searching for
the “mother substance” (synthetic estrogen)
 In the 1950’s, BPA is used to synthesize epoxy
resins and polycarbonate plastics
 Superiority to glass and steel
Vogel 2009
Braun et al 2011
Biello 2008
Image: Wikipedia
Epoxy Resins
 BPA is a monomer in synthesis
 Products:
Protective coatings of medical equipment,
piping, steel drums, and interior of
food/beverage/liquid infant formula cans
Vogel 2009
Groff 2010
US FDA Update 2010
Taylor 2011
Image: http://news.consumerreports.org/a/6a00d83451e0d569e20120a69fcb0e970c-800wi
Polycarbonate (PC) plastics
 Hard plastic formed when BPA is
polymerized
 Products:
Electronics, safety equipment,
automobiles, food containers, plastics
with recycling code # 7, intravenous
tubing, dental sealant, reusable water and
baby bottles
Vogel 2009
Groff 2010
US FDA Update 2010
Image: http://www.pacebutler.com/images/recycle/plastic-recycling-symbols-7.jpg
Thermal (Carbonless) Paper
 Also contains BPA causing transdermal
exposure
 Products:
Sales receipts, cigarette filters, lottery
tickets, fax paper, children’s books, and
recycled paper products
Groff 2010
US EPA DRAFT 2011
Braun 2011
Taylor 2011
Image: http://www.bikudo.com/preview/292638.jpg
Leaching BPA
 Monomers of BPA can hydrolyze and leach into
foods or liquids
 Accelerated by:
 High temperatures
 Acidic or basic conditions
 Damaged surfaces
 Le et al study
。
 Exposure to 100 C (new and used PC water bottles)
allowing 24 hrs to cool to room temperature
 Results: 15-55 fold increase in those exposed to
Groff 2010 heat versus room temperature water only
Braun et al 2011
Biello 2008
Le 2008
Federal Regulation
 1958- FDA approves BPA as indirect food
additive
 Safety determined by toxicity, not
carcinogenicity
 1977- National Cancer Institute (NCI)
initiated 1st carcinogenesis study of BPA due
to increased production
 Responsibility of program passed to the National
Toxicology Program (NTP) during 2 year study
 1988- Environmental Protection Agency (EPA)
defines safe exposure levels to BPA as 50
micrograms/kg body weight
Vogel 2009
Shaw 2008
Health Implications
 Endocrine system
 Cardiovascular Disease
disruption
 Cancer
 Obesity
 Cognitive and
behavior impairment
(CVD)
 Type 2 Diabetes (DM2)
 Asthma
 Liver enzyme
abnormalities
Shaw 2008
Ballard 2010
Image: http://bpafreewaterbottlespro.com/wp-content/uploads/2011/08/bpa-health-risks.jpg
Endocrine System Disruption
 BPA is an endocrine-disrupting compound
(EDC)
 An exogenous agent that interferes with
synthesis, secretion, transport, metabolism,
binding, action, or elimination of natural bloodborne hormones that are present in the body and
are responsible for homeostasis, reproduction,
and developmental processes.
Bourguignon et al 2010
Studies showing BPA as EDC
 Moriyama et al (2002) show BPA inhibiting
thyroid hormone receptor (T3)-mediated
transcription by acting as an antagonist
 Ramos et al (2003) exposed rats to BPA in
utero indicating prenatal exposure induces
transient and permanent age-dependent
alterations in the male reproductive axis at
different levels
Moriyama et al 2002
Ramos 2003
Image: http://electiondebates.com/images/stimulus-pix/rats.png
Studies showing BPA as EDC
 Song et al (2002) demonstrate BPA inducing
NR4A1 gene expression (responsible for
activating steroidogenesis) in mouse
testicular cells
 Akingbemi et al (2004) actually show the
opposite with low doses of BPA showing an
inhibitory effect on testicular
steroidogenesis
Song et al 2002
Akingbemi et al 2004
Metabolic disturbances
 Lang et al use NHANES data to show
higher BPA urine levels associated with
increased prevalence of CVD, DM2, and
liver-enzyme abnormalities
Lang et al 2008
US EPA DRAFT 2011
Image: http://www.online-diabetes-information.com/wp-content/uploads/2011/03/diabetes-heart-disease2.jpg
Young children, infants, and
fetuses at higher risk
 Higher BPA concentrations reflective of
higher food intake per pound of body mass
 Predominant sources:
 Fetus- shown to cross the placenta
 Infants- breast milk, canned infant formula, and
baby bottles
 NICU infants exposed to higher levels due to intensive
medical interventions
 Children- canned food and beverages and school
lunches
Groff 2010
Lang et al 2008
Bourguignon et al 2010
US EPA DRAFT 2011
Image: http://www.sequoiapediatricgroup.com/images/nicu_baby.gif
Exposure outcomes during
development
 Prenatal exposure associated with
aggression and hyperactivity in 2 year
old children
 Delayed breast development with
higher BPA concentrations
 More sensitive to adverse outcomes
due to exposure during development of
neurological and endocrine systems
US EPA DRAFT 2011
Bourguignon et al 2010
US FDA Update 2010
Braun et al 2011
National Children’s Study
 Started 2009
 Examining fetal environment, including
BPA exposure
 Following pregnant women and
offspring until 21 years of age
 Goal of 100,000 children participants
 Largest, most comprehensive study of
its kind in US
Groff 2010
Image: http://www.mrothery.co.uk/images/growth.gif
Metabolism
 Oral ingestion of BPA is metabolized in the
intestines and liver to yield metabolite, BPA
monoglucuronide, and is excreted in the
urine (in humans)
 Acute exposure studies show:
 rapid metabolism of BPA with urinary elimination
to be within 24 hours of exposure based on 4-6
hour half-life
Stahlhut 2009
Lang et al 2008
Image: http://image3.examiner.com/images/blog/wysiwyg/image/water_bottle1(1).jpg
Metabolism Controversy
 BPA monoglucuronide elimination:
 humans/primates- from the blood via
kidneys into urine
Rodents- bile excretion into feces
 Current safety measured on belief that
higher doses result in greater effects
If higher doses cause no harm, lower doses
are deemed safe?
Groff 2010
Lang et al 2008
Taylor et al 2011
Studies Addressing
Controversy
 Stahlhut et al suggest a longer than
expected half life attributed to either
environmental exposure or
accumulation in adipose tissue
 Taylor et al compare bioactive BPA
(unconjugated) levels in primates and
rodents reporting clearance rates are
the same
Stahlhut et al 2009
Taylor et al 2011
Groff 2010
Image: http://maxcdn.fooyoh.com/files/attach/images/3004/141/953/004/Monkey_facepalm.jpg
Exposure
 Over 90% of U.S. individuals have
measurable concentrations of BPA in
their urine
Significantly higher levels of BPA in
younger children, women, and incomes <
$45,000/year
 1997-2005- 115 studies in US, Japan,
and Europe show some effects at or
below the reference dose
Braun et al 2011
Lang et al 2008
Groff 2010
Taylor 2011
Vogel 2009
Image: http://3.bp.blogspot.com/_xo0o9nT5MLI/TOq_bZElPYI/AAAAAAAAAB8/nQspiA_mtwY/s1600/MP900431826.JPG
Back to Federal Regulation
 2007- Chapel Hill Consensus Statement
 BPA, at concentrations found in the human body, is
associated with “organizational changes in prostate,
breast, testes, mammary glands, body size, brain structure
and chemistry, and behavior of laboratory animals.”
 2008- The Center for Evaluation of Risks to Human
Reproduction (CERHR) within the NTP released two
statements regarding BPA at current exposure:
 “some concern for effects on the brain, behavior, and
prostate gland in fetuses, infants, and children”
 “minimal concern for the effects on the mammary gland
and an earlier age for puberty for females in fetuses,
infants, and children”
Vogel 2009
US FDA Update 2010
Image: http://www.knowabouthealth.com/wp-content/uploads/2010/07/BPA.jpg
Current Regulation of BPA
 January 2010- Food and Drug Administration
announces it had some concern about BPA
 November 2010- World Health Organization
recommend holding off on regulations that
limit or ban use of BPA
 Several local and state governments in US
have limited or banned use of BPA
 Oregon Senate Bill:
http://gov.oregonlive.com/bill/2011/SB695/
 October 2011- American Chemistry Council
asks to phase out allowance of BPA in baby
products
US EPA 2010
Brown 2010
USA Today 2011
BPA-free Manufacturers
 By March 2009, major baby bottle companies
removed BPA from products
 Sunoco requires written confirmation of BPA
plastic not sold to children ≤ 3 years
 2010- General Mills announced next tomato
harvest, all Muir Glen tomatoes canned BPAfree
 Eden Foods beans have been BPA free since
Vogel 2009 1999
Szabo 2008
USA Today 2011
Image: http://www.kidsbabydesign.com/wp-content/uploads/2009/06/bpa-free-baby-bottles.jpg
Image: http://www.greenbiz.com/sites/default/files/imagecache/wide_large/0410Muir.jpg
Minimizing Health Risks
 Rudel et al conducted a study
following participants measuring BPA at
baseline and 3 days post intervention
(eliminating canned/packaged foods)
50-70% decrease in urinary BPA
Rudel et al 2011
Image: http://3.bp.blogspot.com/_4J97xRX7uok/TG4Bj2OHSII/AAAAAAAAAAk/DOb-TqhLJh0/s1600/Fresh+foods+vs+Canned+foods.png
Role of the Dietitian
 Counsel public to:
 Avoid canned foods
 Replace recycling #s 3, 6, & 7 with other
recycling #s (1, 2, 4, or 5), stainless steel, or
glassware
 Switch from liquid formula to powdered
 Avoid heating BPA plastic
 Replace canned foods with fresh or frozen foods
 Discard scratched baby bottles/cups
 Only use dishwasher safe and microwave safe
plastics in appliances
Braun 2011
Groff 2010
Bourguignon 2010
US DHHS
Summary
 BPA found in plastics (code # 7) and canned
foods/beverages
 Health implications include endocrine
system disruption, risk of CVD, neurological
impairments, obesity, DM2, and liver enzyme
abnormalities
 No federal limits or bans on uses
 Dietitian can reduce public exposure by
suggesting replacements
Discussion
Image: http://www.sneakerfiles.com/wp-content/uploads/2011/09/Discussion-The-Discussion.jpg
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Bisphenol A: Exposure in the Environment as it Relates to Health