Monday, June 11, 2012

What is Bisphenol-A (BPA)?

Everywhere I look there are labels on baby bottles and other plastic bottles saying that it is "BPA free."  What exactly is BPA and why should we care?  I had mentioned BPA in an earlier blog post about the numbers on the bottom of plastic containers.  I have decided to expand upon this topic with this latest post.

The Food and Drug Administration (FDA) states that BPA "is an industrial chemical that has been present in many hard plastic bottles and metal-based food and beverage cans since the 1960s.  BPA is also found in epoxy resins, which act as a protective lining on the inside of metal-based food and beverage cans."

The National Toxicology Program (which is part of the National Institutes of Health) acknowledges in a brief that BPA is most "commonly described as being 'weakly' estrogenic; however, an emerging body of molecular and cellular studies indicate the potential for a number of additional biological.activities.  These range from interactions with cellular receptors that have unknown biological function to demonstrated effects on receptor signaling systems known to be involved in development."

The scary thing about BPA is that "The highest estimated daily intakes of bisphenol A in the general population occur in infants and children.  Bisphenol A can also be found in breast milk and in the blood of pregnant women, amniotic fluid, placental tissue, and umbilical cord blood indicating some degree of fetal exposure."

"The degree to which bisphenol A migrates from polycarbonate containers into liquid appears to depend more on the temperature of the liquid than the age of the container, i.e., more migration with higher temperatures.   Short-term exposure can occur following application of certain dental sealants or composites made with bisphenol A-derived material such as bisphenol A dimethacrylate (bis-DMA). In addition, bisphenol A is used in the processing of polyvinyl chloride plastic and in the recycling of thermal paper, the type of paper used in some purchase receipts, self-adhesive labels, and fax paper.  Bisphenol A can also be found as a residue in paper and cardboard food packaging materials."

It is alarming the amount of exposure Americans have to BPA.  According to the NTP, "human exposure to BPA is widespread. The 2003-2004 National Health and Nutrition Examination Survey (NHANES III) conducted by the Centers for Disease Control and Prevention (CDC) found detectable levels of BPA in 93% of 2517 urine samples from people six years and older. The CDC NHANES data are considered representative of exposures in the United States. Another reason for concern, especially for parents, may be because some animal studies report effects in fetuses and newborns exposed to BPA."

According to the National Institute of Environmental Health Sciences, "in animal studies, there is some evidence linking BPA exposure with infertility, weight gain, behavioral changes, early onset puberty, prostate and mammary gland cancer and diabetes."  They are funding two-year studies which "will focus on either developmental exposure or adult chronic exposures to low doses of BPA. Researchers will be looking at a number of health effects including behavior, obesity, diabetes, reproductive disorders, development of prostate, breast and uterine cancer, asthma, cardiovascular diseases and transgenerational or epigenetic effects."

Until the research is published:
"The NTP has some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A.
 The NTP has minimal concern for effects on the mammary gland and an earlier age for puberty for females in fetuses, infants, and children at current human exposures to bisphenol A.
 The NTP has negligible concern that exposure of pregnant women to bisphenol A will result in fetal or neonatal mortality, birth defects, or reduced birth weight and growth in their offspring.
 The NTP has negligible concern that exposure to bisphenol A will cause reproductive effects in non-occupationally exposed adults and minimal concern for workers exposed to higher levels in occupational settings."
This view is also supported by the FDA.  However, until the research is presented, the FDA is "supporting reasonable steps to reduce human exposure to BPA, including actions by industry and recommendations to consumers on food preparation."

Since there is much which isn't known about the long-term effects of BPA exposure and given its widespread use, the NTP recommends the following to reduce exposure to BPA:
"Some animal studies suggest that infants and children may be the most vulnerable to the effects of BPA. Parents and caregivers, can make the personal choice to reduce exposures of their infants and children to BPA:

  •  Don’t microwave polycarbonate plastic food containers. Polycarbonate is strong and durable, but over time it may break down from over use at high temperatures.
  • Plastic containers have recycle codes on the bottom. Some, but not all, plastics that are marked with recycle codes 3 or 7 may be made with BPA.
  • Reduce your use of canned foods.
  • When possible, opt for glass, porcelain or stainless steel containers, particularly for hot food or liquids.
  • Use baby bottles that are BPA free."

The Department of Health and Human Services also recommends the following to reduce your exposure to BPA:
HHS supports the American Academy of Pediatrics’ recommendations for infant feeding and supports breastfeeding for at least 12 months whenever possible, as breast milk is the optimal source of nutrition for infants.  
If breastfeeding is not an option, iron-fortified infant formula is the safest and most nutritious alternative.  The benefit of a stable source of good nutrition from infant formula and food outweighs the potential risk of BPA exposure.
Parents should discuss any significant changes to your baby’s diet with your baby’s doctor or nurse. 

Worn baby bottles and cups are likely to have scratches that harbor germs and - if they contain BPA - may release small amounts of the chemical.

Be careful how you heat up your child’s breast milk or formula.  Studies have found there is a very small amount of BPA in plastics and other packaging materials that can transfer to food and liquids.  Additional traces of BPA levels are transferred when hot or boiling liquids or foods come in contact with packaging made of BPA.
Do not put boiling or very hot water, infant formula, or other liquids into BPA-containing bottles while preparing them for your child.
Before mixing water with powdered infant formula, the water should be boiled in a BPA-free container and allowed to cool to lukewarm. 
Ready-to-feed liquid formula can be served at room temperature or gently warmed up by running warm water over the outside of the bottle. 
Always remember:  Do not heat baby bottles of any kind in the microwave – the liquid may heat unevenly and burn your infant
Sterilize and clean bottles according to instructions on infant formula labels.  They should be left to cool to room temperature before adding infant formula.

As a good household practice, only use containers marked “dishwasher safe” in the dishwasher and only use “microwave safe” marked containers in the microwave.
As a good household practice, discard all food containers with scratches, as they may harbor germs and may lead to greater release of BPA."

With all of the "BPA free" alternatives available today, despite the uncertainty over the long-term effects, I think it is important to use alternatives when possible.  There are many places where we cannot control our BPA exposure (like on receipts) that I think we should eliminate exposure in things we can control (plastic containers, etc).  I think it is scary how widespread the use of BPA has become without studies showing its long-term effects.

In case you are bored and want to read more about the subject, the FDA has published several Memorandums regarding a review of low dose studies and exposure to BPA for infants, toddlers and adults from the consumption of infant formula, toddler food and adult (canned) food.  If you're looking for companies that do not use BPA in their cans, the following website has a great list of products which do not use BPA lined cans.

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