What is BPA and Why is it Bad for You?
BPA is an industrial chemical that may find its way into people's food.
Some experts claim that it is toxic, and that people should make an effort to avoid it.
But is BPA really that bad, and should you avoid it at all costs? This is a detailed review of BPA and its health effects.
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 polycarbonate plastics.
These days, BPA-containing plastics are commonly used in food containers, baby bottles and other things.
BPA is also used to make epoxy resins, which are put on the inner lining of canned food containers to keep the metal from corroding and breaking.
Bottom Line: BPA is a synthetic compound found in many plastics, as well as in the lining of canned food containers.
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It's worth noting that many manufacturers have now switched to BPA-free products, in which BPA has been replaced by bisphenol-S (BPS) or bisphenol-F (BPF).
However, recent research reports that 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 the solution ().
Plastic items labeled with the recycling numbers 3 and 7 or the letters "PC" likely contain BPA, BPS or BPF.
Bottom Line: BPA and its alternatives — BPS and BPF — may be found in many commonly used products, which are often labeled with recycling codes 3, 7 or the letters "PC."
The main source of BPA exposure is through your diet ().
That's because when BPA containers are made, not all the BPA gets sealed into the product. This allows part of it to break free and mix with the container's contents once food or fluids are added (, ).
For instance, a recent study found that BPA levels in urine decreased by 66% following 3 days of avoiding packaged foods ().
Another study had participants eat one serving of either fresh or canned soup daily for 5 days. Urine levels of BPA were 1,221% higher in those who consumed the canned soup ().
Additionally, the World Health Organization (WHO) reported that BPA levels in breastfed babies were up to 8 times lower than those measured in babies fed liquid formula from BPA-containing bottles ().
Bottom Line: The diet is by far the biggest source of BPA for humans, particularly packaged foods and canned foods. Babies fed formula from BPA-containing bottles also have high levels in their bodies.
Many experts claim that BPA is harmful, but others disagree.
This section explains what BPA does in the body, and why its health effects remain controversial.
BPA's Biological Mechanisms
BPA is said to mimic the structure and function of the hormone estrogen ().
Due to its estrogen-like shape, BPA can bind to estrogen receptors and influence bodily processes, such as growth, cell repair, fetal development, energy levels and reproduction.
In addition, BPA may also have the ability to interact with other hormone receptors, such as thyroid hormone receptors, thus altering their function ().
Your body is sensitive to changes in hormone levels, which is the reason why BPA's ability to mimic estrogen is believed to affect your health.
The BPA Controversy
Given the information above, many people wonder whether BPA should be banned.
Its use has already been restricted in the EU, Canada, China and Malaysia, particularly in products for babies and young children.
Some US states have followed suit, but no federal regulations have been instituted.
In 2014, the released its latest report, which confirmed the original 1980s daily exposure limit of 50 mcg/kg (about 23 mcg/lb) daily and concluded that BPA is probably safe at the levels currently allowed ().
However, research in rodents shows negative effects of BPA at much lower levels, as little as 10 mcg/kg daily. Also, research in monkeys shows that levels equivalent to those currently measured in humans have negative effects on reproduction (, ).
A review from 2006 may help explain the discrepancies. It revealed that all the industry-funded studies found no effects of BPA exposure, while 92% of the studies not funded by industry found significant negative effects ().
Bottom Line: BPA has a similar structure as the hormone estrogen. It may bind to estrogen receptors and affect the function of your body.
BPA may affect several aspects of fertility.
One study observed that women with frequent miscarriages had about 3 times as much BPA in their blood as women with successful pregnancies ().
What's more, studies of women undergoing fertility treatments showed those with higher levels of BPA to have proportionally lower egg production and be up to 2 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 sex-life satisfaction than other men ().
However, although the effects above are notable, several recent reviews agree that more studies are needed to strengthen the body of evidence (, , , ).
Bottom Line: Several studies have shown that BPA can negatively affect many aspects of both male and female fertility.
Most studies — but not all — have observed that children born to mothers exposed to BPA at work weigh up to 0.5 lbs (or 0.2 kg) less at birth than children of unexposed mothers (, , ).
Children born to BPA-exposed parents also tended to have a shorter anogenital distance, 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 the risk of cancer.
However, while there are ample animal studies to support this, human studies are less conclusive (, , , , , ).
Bottom Line: BPA exposure during early life may influence birth weight, hormonal development, behavior and cancer risk in later life.
Human studies have examined the link between BPA levels and blood pressure.
They reported a 27–135% greater risk of high blood pressure in people with high BPA levels (, ).
Moreover, a survey of 1,455 Americans linked higher BPA levels to an 18-63% greater risk of heart disease, and a 21-60% greater risk of diabetes ().
In a later study, higher BPA levels were linked to a 68-130% higher risk of developing type 2 diabetes ().
Finally, participants with the highest BPA levels were 37% more likely to have insulin resistance, a key driver of the metabolic syndrome and type 2 diabetes ().
However, some studies found no links between BPA and these diseases (, , ).
Bottom Line: Higher BPA levels seem to be linked to an increased risk of type 2 diabetes, high blood pressure and heart disease.
Obese women were observed to have 47% higher BPA levels than their normal-weight counterparts ().
Several studies also report participants with the highest BPA levels to be 50–85% more likely to be obese and 59% more likely to have a large waist circumference. Not all studies confirm these findings though (, , , , , ).
Interestingly, similar patterns were observed in children and adolescents (, ).
However, although prenatal exposure to BPA was linked to increased weight gain in animal models, this has not been strongly confirmed in humans (, ).
Bottom Line: BPA exposure is linked to an increased risk of obesity and increased waist circumference. However, more research is needed.
BPA exposure may also be linked to the following health issues:
- Polycystic ovary syndrome (PCOS): BPA levels were observed to be 46% higher in women with PCOS, compared to their healthy counterparts ().
- Premature delivery: Women with higher BPA levels during pregnancy were 91% more likely to deliver before 37 weeks ().
- Asthma: Higher prenatal exposure to BPA, especially at week 16, was linked to a 130% higher risk of wheezing in infants under 6 months. Early childhood exposure to BPA was also linked to wheezing in later childhood (, ).
- Liver function: Higher BPA levels were linked to a 29% higher risk of abnormal liver enzyme levels ().
- Immune function: BPA levels may be linked to worse immune function ().
- Thyroid function: Higher BPA levels were linked to abnormal levels of thyroid hormones, indicating impaired thyroid function (, , ).
- Brain function: African green monkeys exposed to BPA levels judged safe by the showed loss of connections between brain cells ().
Bottom Line: BPA exposure has also been linked to several other health problems. More research is needed to confirm these findings.
Chances are that you want to try to avoid BPA, given the negative effects in so many studies.
Although avoiding it completely may be impossible, there are some ways to get rid of most of it.
Here are a few effective ways to minimize your exposure to BPA:
- Avoid packaged foods: Eat mostly fresh, whole foods. Stay away from canned foods or foods packaged in plastic containers labeled with recycling numbers 3, 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.
- Be selective with toys: Make sure that plastic toys you buy for your child 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 recommend powders over liquids from BPA containers, as liquid is likely to absorb more BPA from the container.
Bottom Line: There are several simple ways to significantly reduce your exposure to BPA from the diet and environment.
In light of the evidence, taking steps to limit your BPA exposure is probably a good idea.
In particular, pregnant women may benefit from making an effort to avoid BPA as much as possible, especially during the early stages of pregnancy.
As for others, occasionally drinking from a "PC" plastic bottle or eating from a can is probably not a reason to panic.
That being said, swapping plastic containers for BPA-free ones requires very little effort for a potentially big impact.
Plus, when it comes to your diet, the fresh whole foods linked to optimal health rarely come packaged in containers with BPA.