Bisphenol-A (BPA) And Why Is Bpa Bad?
BPA is a structural component in polycarbonate beverage bottles. It is also a component in metal can coatings, which protect the food from directly contacting metal surfaces. BPA has been used in food packaging since the 1960s.
As is the case when foods are in direct contact with any packaging material, small, measurable amounts of the packaging materials may migrate into food and can be consumed with it. As part of its premarket review of food packaging materials, FDA’s food contact regulations and food contact notification program assesses the likely migration from the packaging material to assure that any migration to food occurs at safe levels.
Heightened interest in the safe use of BPA in food packaging has resulted in increased public awareness as well as scientific interest. As a result, many exploratory scientific studies have appeared in the public literature. Some of these studies have raised questions about the safety of ingesting the low levels of BPA that can migrate into food from food contact materials.
To address these questions the National Toxicology Program, partnering with FDA’s National Center for Toxicological Research is carrying out in-depth studies to answer key questions and clarify uncertainties about BPA.
On the regulatory front, FDA’s regulations authorize FDA to amend its food additive regulations to reflect when certain uses of an additive have been abandoned. FDA can take this action on its own initiative or in response to a food additive petition that demonstrates that a use of a food additive has been permanently and completely abandoned.
Recently, FDA granted two petitions requesting that FDA amend its food additive regulations to no longer provide for the use of certain BPA-based materials in baby bottles, sippy cups, and infant formula packaging because these uses have been abandoned. As a result, FDA amended its food additive regulations to no longer provide for these uses of BPA.
Bisphenol A (BPA) is an organic synthetic compound with the chemical formula (CH3)2C(C6H4OH)2 belonging to the group of diphenyln methane derivatives and bisphenols, with two hydroxyphenyl groups. It is a colorless solid that is soluble in organic solvents, but poorly soluble in water (0.344 wt % at 83 °C).
Bisphenol A (BPA) is a chemical produced in large quantities for use primarily in the production of polycarbonate plastics and epoxy resins.
BPA is a starting material for the synthesis of plastics, primarily certain polycarbonates and epoxy resins, as well as some polysulfones and certain niche materials. BPA-based plastic is clear and tough, and is made into a variety of common consumer goods, such as plastic bottles including water bottles, sports equipment, CDs, and DVDs.
Epoxy resins containing BPA are used to line water pipes, as coatings on the inside of many food and beverage cans and in making thermal paper such as that used in sales receipts. In 2015, an estimated 4 million tonnes of BPA chemical were produced for manufacturing polycarbonate plastic, making it one of the highest volume of chemicals produced worldwide.
BPA is a xenoestrogen, exhibiting estrogen-mimicking, hormone-like properties that raise concern about its suitability in some consumer products and food containers. Since 2008, several governments have investigated its safety, which prompted some retailers to withdraw polycarbonate products.
The U.S. Food and Drug Administration (FDA) has ended its authorization of the use of BPA in baby bottles and infant formula packaging, based on market abandonment, not safety.The European Union and Canada have banned BPA use in baby bottles.
What Is BPA?
BPA (bisphenol A) is a chemical that is added to many commercial products, including food containers and hygiene products.
It was first discovered in the 1890s, but chemists in the 1950s realized that it could be mixed with other compounds to produce strong and resilient plastics.
These days, BPA-containing plastics are commonly used in food containers, baby bottles, and other items.
BPA is also used to make epoxy resins, which are spread on the inner lining of canned food containers to keep the metal from corroding and breaking.
Which Products Contain It?
Common products that may contain BPA include:
- Items packaged in plastic containers
- Canned foods
- Feminine hygiene products
- Thermal printer receipts
- CDs and DVDs
- Household electronics
- Eyeglass lenses
- Sports equipment
- Dental filling sealants
It’s worth noting that many BPA-free products have merely replaced BPA with bisphenol-S (BPS) or bisphenol-F (BPF).
However, even small concentrations of BPS and BPF may disrupt the function of your cells in a way similar to BPA. Thus, BPA-free bottles may not be an adequate solution.
Plastic items labeled with the recycling numbers 3 and 7 or the letters “PC” likely contain BPA, BPS, or BPF.
Where is BPA found?
Polycarbonate plastics have many applications including use in some food and drink packaging, e.g., water and infant bottles, compact discs, impact-resistant safety equipment, and medical devices. Epoxy resins are used as lacquers to coat metal products such as food cans, bottle tops, and water supply pipes. Some dental sealants and composites may also contribute to BPA exposure.
How does BPA get into the body?
The primary source of exposure to BPA for most people is through the diet. While air, dust, and water are other possible sources of exposure, BPA in food and beverages accounts for the majority of daily human exposure.
Bisphenol A can leach into food from the protective internal epoxy resin coatings of canned foods and from consumer products such as polycarbonate tableware, food storage containers, water bottles, and baby bottles. The degree to which BPA leaches from polycarbonate bottles into liquid may depend more on the temperature of the liquid or bottle, than the age of the container. BPA can also be found in breast milk.
Why are people concerned about BPA?
One reason people may be concerned about BPA is because 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.
If I am concerned, what can I do to prevent 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.
May Cause Infertility in Men and Women
BPA may affect several aspects of your fertility.
One study observed that women with frequent miscarriages had about three times as much BPA in their blood as women with successful pregnancies.
What’s more, studies of women undergoing fertility treatments showed that those with higher levels of BPA have proportionally lower egg production and are up to two times less likely to become pregnant.
Among couples undergoing in vitro fertilization (IVF), men with the highest BPA levels were 30–46% more likely to produce lower-quality embryos.
A separate study found that men with higher BPA levels were 3–4 times more likely to have a low sperm concentration and low sperm count.
Additionally, men working in BPA manufacturing companies in China reported 4.5 times more erectile difficulty and less overall sexual satisfaction than other men.
Although such effects are notable, several recent reviews agree that more studies are needed to strengthen the body of evidence.
Negative Effects on Babies
Most studies — but not all — have observed that children born to mothers exposed to BPA at work weigh up to 0.5 pounds (0.2 kg) less at birth, on average, than children of unexposed mothers.
Children born to parents exposed to BPA also tended to have a shorter distance from the anus to the genitalia, which further points to BPA’s hormonal effects during development.
In addition, children born to mothers with higher BPA levels were more hyperactive, anxious, and depressed. They also showed 1.5 times more emotional reactivity and 1.1 times more aggressiveness.
Finally, BPA exposure during early life is also thought to influence prostate and breast tissue development in ways that increase cancer risk.
However, while there are ample animal studies to support this, human studies are less conclusive.
Use BPA-free products.
Manufacturers are creating more and more BPA-free products. Look for products labeled as BPA-free. If a product isn’t labeled, keep in mind that some, but not all, plastics marked with recycle codes 3 or 7 may be made with BPA.
Cut back on cans.
Reduce your use of canned foods since most cans are lined with BPA-containing resin.
The National Institute of Environmental Health Sciences, part of the National Institutes of Health, advises against microwaving polycarbonate plastics or putting them in the dishwasher, because the plastic may break down over time and allow BPA to leach into foods.
Use glass, porcelain or stainless steel containers for hot foods and liquids instead of plastic containers.
Fast Risk facts on bisphenol A, or BPA
Here are some key points about BPA. More detail is in the main article.
- BPA is present all around us in the environment and in manufactured products.
- Research has linked exposure to fertility problems, male impotence, heart disease and other conditions.
- Some reports say that current levels of BPA are low and not a danger to humans.
- Tips for avoiding exposure include breastfeeding infants and not buying food in plastic packaging.
BPA is an endocrine disruptor.
It can imitate the body’s hormones, and it can interfere with the production, secretion, transport, action, function, and elimination of natural hormones.
BPA can behave in a similar way to estrogen and other hormones in the human body.
Infants and young children are said to be especially sensitive to the effects of BPA.
Research suggests it can impact human health in various ways.
In 2013, scientists from Brigham and Women’s Hospital published findings showing that BPA exposure can affect egg maturation in humans.
A review of previous studies, published in 2015, found evidence that BPA can interfere with endocrine function involving the hypothalamus and the pituitary gland.
The researchers suggested that this type of action can affect puberty and ovulation, and that it may lead to infertility.
The authors add: “The detrimental effects on reproduction may be lifelong and transgenerational.”
Male impotence may be affected, according to a study that looked at the effect of men’s exposure to BPA at work. Findings indicated that high-level exposure may increase the risk of erectile dysfunction and problems with sexual desire and ejaculation
Research has linked even low-dose BPA exposure to cardiovascular problems, including coronary artery heart disease, angina, heart attack, hypertension, and peripheral artery disease.
Findings suggest that this type of exposure could trigger arrhythmias, atherosclerosis, and blood pressure changes.
Type 2 diabetes and body weight
There is evidence that low-level exposure to BPA could contribute to insulin resistance and therefore diabetes type 2. Less reliable evidence indicates that it may also impact body weight.
Fetal brain development
Environmental exposure to BPA has the potential to affect the developing brain during gestation, according to research.
The impact includes changes in structural development, interference with estrogen regulation, DNA modifications. This could have effects on social behavior and anxiety after birth.
Breast and prostate cancer
Scientists believe BPA, with its estrogen-like behavior, could increase the risk of breast, prostate, and other cancers in people who were exposed to it in the womb.
In 2015, a group of researchers concluded that “Fetal exposure to BPA could lead to “long-lasting” effects on the carcinogenesis of certain organs,” potentially leading to the development of hormone-related cancers.
Scientists have also found that BPA could interfere with the effectiveness of chemotherapy in breast cancer treatment.
A systematic review published in 2016 found that exposure to BPA before birth increased the risk of wheezing and asthma, especially if it occurred during the second trimester.
Higher BPA levels are linked to a 29% higher risk of abnormal liver enzyme levels.
BPA levels may contribute to worse immune function.
Higher BPA levels are linked to abnormal levels of thyroid hormones, indicating impaired thyroid function.
African green monkeys exposed to BPA levels judged safe by the Environmental Protection Agency (EPA) showed loss of connections between brain cells.
Public authorities set BPA safety levels, but concerns remain about degrees of exposure.
One study by the Centers for Disease Control and Prevention (CDC) found BPA in nearly all human urine samples, suggesting that exposure is widespread across the United States (U.S.).
The CDC note that people are commonly exposed to low levels of BPA when they consume food or water that has been stored in containers made with the chemical.
Children may also be exposed by touching items that are made with BPA and then putting their hands in their mouth, or by putting their mouth on the item.
Other means of exposure include:
- having dental sealants that contain BPA
- working in places that manufacture products with BPA in them
- using harsh detergents, high-temperature liquids, or products that contain acidic liquids to clean containers
Thermal paper and carbonless paper may also contain varying levels of BPA, which gets onto the hands and fingers. Thermal paper is commonly used in movie theater tickets and labels.
BPA probably enters the system when the fingers are placed in the mouth, rather than through the skin.
A study of 77 Harvard College students found one week of drinking water from polycarbonate bottles increased the levels of BPA in by two-thirds. This suggests that regular consumption of water from such bottles significantly increases exposure to BPA.
BPA is used in infant’s feeding bottles, so breast-feeding an infant is likely to reduce levels of BPA exposure.
How serious is the risk?
In August 2010, a report by the National Toxicology Program concluded that current levels of BPA raise:
- some concern about the effect on the brain, on behavior, and on the prostate gland in fetuses, infants, and children
- minimal concern about the effect on the mammary gland and early puberty
- negligible concern that BPA exposure will lead to fetal abnormalities, low birth weight, and reproductive problems
While these sources of potential exposure are recognized, a report about the hazards of BPA for the World Health Organization (WHO), points out that exposure rates in investigations tend to be higher than those estimated to exist in most environments.
The United States (U.S.) Food and Drug Administration (FDA) continues to support the use of BPA in current food packaging, because the amount that leaches into food is small.
It is difficult to avoid BPA because it is so prevalent in the environment, but some tips can help to minimize exposure:
- check for a BPA-free label on foods and packaging
- buy and store foods in glass jars, not plastic
- use fresh, frozen, or dried products, not canned
- avoid microwaving foods in plastic containers
- do not wash plastic containers in the dishwasher or use harsh detergents on them
- choose wooden toys instead of plastic
- breast feed infants as far as possible, instead of bottle feeding
One study has suggested that, after just 3 days of eating a fresh food diet with no products taken from a can or plastic packaging, the levels of BPA in participants’ bodies fell significantly.
How to Minimize Your Exposure
Given all of the potential negative effects, you may wish to avoid BPA.
Although eradicating it completely may be impossible, there are some effective ways to reduce your exposure:
- Avoid packaged foods: Eat mostly fresh, whole foods. Stay away from canned foods or foods packaged in plastic containers labeled with recycling numbers 3 or 7 or the letters “PC.”
- Drink from glass bottles: Buy liquids that come in glass bottles instead of plastic bottles or cans, and use glass baby bottles instead of plastic ones.
- Stay away from BPA products: As much as possible, limit your contact with receipts, as these contain high levels of BPA.
- Be selective with toys: Make sure that plastic toys you buy for your children are made from BPA-free material — especially for toys your little ones are likely to chew or suck on.
- Don’t microwave plastic: Microwave and store food in glass rather than plastic.
- Buy powdered infant formula: Some experts recommend powders over liquids from BPA containers, as liquid is likely to absorb more BPA from the container.