The chemical in your baby’s bottle

The Chemical in Your Baby’s Bottle

 

…One chemical that has received a lot of attention lately is Bisphenol A, or BPA, an ingredient in plastics used to make reusable food and beverage containers (including baby bottles). It also coats the insides of food and beverage cans. Humans come in contact with it mainly through eating, but inhalation and absorption through the skin have not been ruled out. Regular exposure to BPA, including among infants and children, is shown by its presence in blood, amniotic fluid, umbilical cords, and breast milk. Additionally, the US Centers for Disease Control and Prevention detected BPA in the urine of 92.6 percent of the more than 2,500 Americans examined; levels were higher in children and adolescents than adults.

While BPA has its benefits, like preventing interactions between food items and metal cans, it has the biological actions of the female hormone estrogen. Why should we worry about that? Exposure to estrogenic chemicals during the time when our organs are developing, specifically during the fetal and neonatal periods and puberty, is a risk factor for breast and prostate cancers, malformations of reproductive organs, infertility, and alterations in brain development.

BPA was originally synthesized in 1891; in the 1930s it was considered for pharmaceutical use because of its estrogenic properties but was abandoned when diethylstilbestrol (DES) was found to be a more potent synthetic estrogen. DES was prescribed to at least 2 million women to prevent miscarriage under the assumption that during pregnancy “some estrogen is good, so more must be better.” By 1971, girls exposed to DES in the womb had developed an extremely rare vaginal cancer typically found in elderly women. This caused the Food and Drug Administration to ban its use by pregnant women.

 

…Since the chemical revolution when BPA and hundreds of other common chemicals containing hormonal agents were added to our lives, the incidence of many diseases and disorders has been on the rise, including early puberty, obesity, reduced sperm count, hyperactivity, genital malformations, breast cancer and prostate cancer. BPA has caused all of these in laboratory animals. Last year, a study of 1,455 adults, published in The Journal of the American Medical Association, showed a positive correlation between urinary BPA levels and diabetes and heart disease.

BPA is regulated by the US Environmental Protection Agency, which considers 50 parts per million of BPA per day to be a safe dose. However, over 100 animal studies have found effects well below this dose. In fact, scientists have yet to find a harmless dose of BPA.

Why hasn’t BPA been banned? Mostly because BPA exposure cannot be associated with a single disease; the effects can be subtle and complications may appear years later. Animal studies revealed that BPA exposure during gestation contributed to behavioral disorders, obesity, diabetes, early puberty, breast cancer, prostate cancer, and infertility. In 2007, 38 international specialists on BPA signed the Chapel Hill Consensus Statement at a meeting organized by the National Institutes of Environmental Health Sciences: Such a wide range of harmful effects, though found in laboratory animals, provided “great cause for concern” for “the potential for similar adverse effects in humans.” Experts at the National Toxicology Program agreed….

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FDA’s conclusion that chemical is safe is flawed

WASHINGTON – An independent panel of science advisers is taking issue with the FDA’s assessment that a controversial chemical is safe.

In a report to the agency, the panel concluded: “The margins of safety identified by FDA as ‘adequate’ are, in fact, inadequate.”

The chemical, known as bisphenolA, is used to make plastic baby bottles and sealants for cans that contain food. Environmental groups are seeking to have it banned in products for young children.

The advisers found that the FDA had not considered all the scientific evidence available in concluding that BPA is safe.

oct/2008

Baby Bottles, Cans, and Bisphenol-A

Plastic Baby Bottles and Bisphenol-A

http://www.nytimes.com/2008/09/06/opinion/06sat4.html

What do you do when one arm of the government says everything is O.K. and another tells you to watch out? That is what is happening with bisphenol-A — a chemical used in many plastics and epoxy resins now found in baby bottles and liners for canned goods. The answer is a truism in every family rulebook — when in doubt, especially when it comes to children, err on the side of caution. That means it is a good idea to keep the young away from bisphenol-A, or BPA.

The Food and Drug Administration said last month that the small amounts of BPA that leach out of containers and into food or milk are not dangerous. Then this week, the National Toxicology Program, the federal agency for toxicological research, reported that their research shows “some concern” about the effects of BPA on the brain development and behavior of fetuses and young children.

A new study by the Yale School of Medicine is cause for even more concern. In tests on primates, researchers found that BPA “causes the loss of connections between brain cells” that could cause memory or learning problems and depression.

Scientists from the toxicology offer this advice:

¶ Watch for the numeral 7 on the bottom of plastic containers. That often means they contain BPA.

¶ Don’t microwave plastic food containers made with BPA. Better to use glass or porcelain.

¶ Watch out for canned foods for children.

¶ Search for baby bottles and other baby products that are BPA-free.

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More Evidence That BPA Found in Clear Plastics Impairs Brain Function

Yale School of Medicine

New Haven, Conn. — Yale School of Medicine researchers reported today that the chemical bisphenol-A (BPA), a building block for polycarbonate plastics found in common household items, causes the loss of connections between brain cells. This synaptic loss may cause memory/learning impairments and depression, according to study results published in the Proceedings of the National Academy of Sciences (PNAS).

Unlike previous studies that looked at the effect of BPA on rodents, the team examined the effects in a primate model. They also used lower levels of the chemical than in past studies. “Our goal was to more closely mimic the slow and continuous conditions under which humans would normally be exposed to BPA,” said study author Csaba Leranth, M.D., professor in the Department of Obstetrics, Gynecology & Reproductive Sciences and in Neurobiology at Yale. “As a result, this study is more indicative than past research of how BPA may actually affect humans.”

Over a 28-day period, Leranth and his team gave each primate 50 micrograms/kg of BPA per day, adjusted for body weight, the amount considered safe for human consumption by the Environmental Protection Agency (EPA). The team also administered estradiol, the major form of hormonal estrogen that modulates nerve cell connections in the brain. Best known as one of the principal hormone products of the ovary, estrogen has also been shown in past studies to be synthesized in the brain, where it aids the development and function of the hippocampus and prefrontal cortex.

The team then used an electron microscope to count nerve cell connections in the brain. They found that BPA inhibits creation of the synaptic connections in the hippocampus and prefrontal cortex, areas of the brain involved with regulation of mood and formation of memory.

 “Our primate model indicates that BPA could negatively affect brain function in humans,” said study co-author Tibor Hajszan, M.D., associate research scientist in Yale Ob/Gyn. “Based on these new findings, we think the EPA may wish to consider lowering its ‘safe daily limit’ for human BPA consumption.”

Hajszan said that although daily exposure of an average person to BPA usually does not reach the level that was applied in this study, human exposure to BPA is not limited to a single month, but rather is continuous over a lifetime. “The negative effect of BPA may also be amplified when estradiol levels are naturally lower than in healthy adults. That is why exposure to BPA may particularly be risky in the case of babies and the elderly.”

Other authors on the study included Klara Szigeti-Buck, Jeremy Bober and Neil J. MacLusky.

The study was supported by the National Institutes of Health and by a National Alliance for Research on Schizophrenia and Depression Young Investigator Award.

Citation: PNAS Online Early Edition, 10.1073/pnas.0806139105 (September 2, 2008)