Is plastic bad for your health?
In October 2008, the Canadian government took the first steps to ban products containing the chemical bisphenol A (BPA), a common compound found in plastics, because of its adverse effects on human health. The North American National Toxicology Program, after examining 400 recent studies on the effects of BPA, identified â€œsome concern for neural and behavioral effects in fetuses, infants, and childrenâ€ and â€œsome concern for exposure in these populations based on effects in the prostate gland, mammary gland, and an earlier age for puberty in femalesâ€.
On March 13 this year, the US Senate proposed a bill banning the use of BPA and, in a pre-emptive strike, a number of large chain department stores stopped stocking infant products containing BPA. Six of the major baby-bottle manufacturers in the US have now switched to BPA-free plastics. Even more significantly, one of the major international chemical producers has declared it will no longer supply BPA to manufacturers for use in products designed for children under three years of age.
In Australia, the issue of BPA has received less attention and many suppliers of plastic goods donâ€™t even know what BPA is, let alone whether or not their products contain it. Food Standards Australia and New Zealand (FSANZ) claims to have â€œa close eyeâ€ on research concerning the health risks of BPA and is monitoring the developments in Canada and the US. However, FSANZâ€™s stance on BPA at present is based on a European Food Safety Authority (EFSA) study that set a â€œsafeâ€ limit for exposure to BPA and concluded that the amount of BPA we consume via plastic containers and canned foods is below that threshold.
To date, the official word on BPA in Australia is that the use of BPA in food packaging and drink containers â€œdoes not pose a significant health riskâ€, despite a growing body of evidence to the contrary. Many Australians are still in the dark about BPA. So what is it? How does it affect health? Should we be avoiding products containing BPA and, if so, how do we identify them? These are all questions every parent should know the answers to.
What is BPA?
BPA is an industrial chemical that has been widely used for the past 50 or 60 years, mainly as a component of plastics. It is also a key ingredient in the manufacture of epoxy resins. Plastics containing BPA are common and the most widely used is polycarbonate. Polycarbonate plastic is a hard, clear, almost glass-like plastic widely used because of its strength and ability to withstand significant impact without shattering. Among its most common uses, the most concerning in terms of health risk is the production of infant feeding bottles and of re-useable food and drink containers. Aside from polycarbonate food containers, epoxy resins containing BPA are commonly used to line aluminium food and soft drink cans and it is sometimes used in the lining of baby formula containers.
What makes the use of BPA in food containers dangerous is its propensity to leach from the plastic containers into whatever food or drink is inside. The amount of BPA leached is significantly increased when the plastic is scratched or heated. Evidence of BPA leaching into foods is clear and not disputed by the plastics or chemical industries. In 2003â€“2004, the US Center for Disease Control conducted a study involving 2517 people aged six and over. BPA was found in the urine of 92.6 per cent of participants.
BPA as a health risk
While there is no doubt that BPA leaches from plastics and cans into food and drink, the ongoing dispute between scientists centres on how BPA affects human health and at what level of exposure these effects are seen. As is the case with many toxic substances, food and drug authorities have determined what they call a â€œsafeâ€ maximum daily limit of ingested BPA. The EFSA set this limit at 0.05 milligrams (50 micrograms) per kilo of body weight, despite some studies suggesting there are discernible health effects in rats exposed to levels of BPA as low as 0.025 micrograms per kilo of body weight. The Journal of the American Medical Association has criticised the â€œsafeâ€ levels that have been set by food and drug authorities around the world, suggesting they are based on old data and outdated testing methods. Other commentators express concern about the cumulative effects of ingested BPA.
BPA is an endocrine disruptor that mimics oestrogen in the body. In animal studies, consumption of BPA at levels lower than those deemed â€œsafeâ€ by food and drug authorities has been linked to increased risk of cancer, particularly breast and prostate, as well as early onset of puberty, reproductive dysfunction, birth defects and neuro-toxicity. Behavioural changes and reduced capacity to gender differentiate have also been observed.
While many studies have been done on the effects of BPA on animals, the data on the effects of BPA in humans are a little thinner on the ground. Conflicting studies have been criticised by both the chemical suppliers and plastics manufacturers on the one hand and anti-BPA lobby groups on the other. Not surprisingly, many of the studies refuting the health risks associated with exposure to BPA are industry-funded.
One of the first studies on the effects of BPA consumption in humans was released late last year. It found that high levels of BPA in urine were associated with increased risk of heart disease, higher risk of obesity and clinically abnormal concentrations of certain liver enzymes. The conclusion of the study, published in the Journal of the American Medical Association, was that â€œhigher BPA exposure, reflected in higher urinary concentrations of BPA, may be associated with avoidable morbidity in the community-dwelling adult populationâ€. While this conclusion is somewhat vague, it does suggest there is a real, identifiable health risk.
Other human studies, although limited in scope and sample size, have nonetheless pointed to concerns that high levels of BPA are linked to high levels of testosterone in both men and women, polycystic ovarian syndrome in women, recurrent miscarriage and chromosomal defects in foetuses. Despite the limitations of these studies, collectively they suggest that further and more widespread research is necessary.
The National Toxicity Program in the US closely examined all available data late last year and concluded: â€œThere is some concern for neural and behavioral effects in fetuses, infants, and children at current human exposures. The NTP also has some concern for bisphenol A exposure in these populations based on effects in the prostate gland, mammary gland, and an earlier age for puberty in females.â€
Who is most at risk?
Exposure to BPA is potentially dangerous to people of any age, but it is of particular concern in young babies and children. At most risk of excessive exposure to BPA are bottle-fed babies. According to the US Department of Health and Human Services, a formula-fed infant may consume up to 11 micrograms per day compared with an adult at 1.5 micrograms. BPA leaches from bottles when the surface of the plastic is scratched as a result of cleaning agents, when they are heated to high temperatures for sterilising and when they are filled with warm liquids or heated in microwave ovens.
Combined with the possibility of BPA leaching into formula from the lining of some cans, this leads to exposure well above that found in the general population. Given that the effects of BPA have been found to be most harmful at the early developmental stage of life, excessive exposure to BPA in infants is very worrying to say the least.
How to avoid BPA
There are several things you should consider when buying packaged foods and plastics if you wish to minimise yours and your familyâ€™s exposure to BPA. Itâ€™s not always easy to identify cans that are lined with resins containing BPA, so if possible avoid canned foods â€” glass jars are safer. Canned baby formula in Australia is generally safe. According to the manufacturers, Heinz, Karicare, S26, Novalac and Bellamy formulas are all packaged in BPA-free cans. Beware of liquid formulas, though, as these are more likely to contain BPA.
Sugary soft drinks are detrimental to health in other ways, including those with sugar substitutes, but if you must buy them, buy bottles rather than cans and keep them in the fridge. Most soft drink, juice and small water bottles are made from PET plastic, which does not contain BPA.
When buying plastics for food storage or baby bottles, there are two factors that will help to identify whether or not they contain BPA. Polycarbonate is the plastic most likely to contain BPA and can generally be identified by the way it looks and feels. Polycarbonate is a hard plastic, so when you press against it there is no give. It may be clear or coloured and will have a glass-like appearance. Plastics that feel a little flexible, such as those used for bottled water, or that have a milky appearance are not polycarbonate. Some baby-bottle manufacturers use a hard plastic similar in appearance to polycarbonate, but with a honey-coloured tinge. This plastic is BPA-free.
Choose stainless steel or aluminium flasks for kidsâ€™ drink bottles. Not only can you be sure they are BPA free, but they also wonâ€™t harbour bacteria that can make your kids sick. Wrap sandwiches in brown paper rather than clingwrap or plastic sandwich bags as these may contain BPA (they are also bad for the environment). Most lunchbox-style containers are BPA-free but there are many food storage containers that are made from polycarbonate. These should be fairly easy to identify by their appearance.
Aside from the look of the plastic, the recycling symbol is a good indicator of whether or not the plastic is likely to contain BPA. Plastics are separated into seven categories that are identified by the recycling symbol (three arrows forming a triangle) and the number inside. The symbol is often found on the bottom of the container. Types 1, 2, 4, 5 and 6 are BPA-free. Type 3 plastics are PVC and may contain BPA. Type 7 represents all â€œotherâ€ plastics, including polycarbonate, so while not all plastics categorised as type 7 contain BPA, itâ€™s best to avoid them unless they are labelled â€œBPA freeâ€.
The best policy to avoid BPA is to buy only what you know to be BPA-free, so if in doubt itâ€™s better to give it a miss and look for an alternative. Twelve months ago, it was much harder to find baby bottles that were BPA-free, but the actions in the US and Canada have led to a large number of baby-bottle manufacturers switching to BPA-free plastics, so there is no reason to use polycarbonate bottles any more. BPA-free baby products are widely available.
The bottom line
While there is still raging debate within the scientific community over whether or not BPA presents a health risk at low-level exposure, what most manufacturers will concede is that BPA does leach. Unfortunately for consumers, food authorities have a tendency to decide on our behalf what levels of exposure to toxic chemicals are â€œsafeâ€. Despite denials from chemical suppliers and plastics manufacturers, there is an increasing number of independent studies that suggest there is no â€œsafeâ€ level of BPA for humans, in particular for babies and children.
With that in mind, itâ€™s up to parents to choose whether or not they are prepared to take the chance on the health effects and vote with their wallets. Given the number of BPA-free products that are now available, itâ€™s easy to avoid unnecessary risk. The sweeping changes already seen in the baby products industry have been the result of consumer pressure rather than government regulation. If consumers continue to exert pressure on manufacturers, BPA in any kind of food containers will become a thing of the past.
The following baby bottles and sipper cups are readily available and BPA-free:
Beware of water purifiers. Many of the jug-type, benchtop water purifiers are made with polycarbonate plastic and contain BPA. If you want to use a purifier, choose ceramic under-sink units or benchtop purifier/chillers that have stainless-steel bowls.