What is BPA?
Bisphenol-A (BPA) is an industry chemical used to make polycarbonate plastic resins, epoxy resins and other products since 1957. It is used primarily to harden plastics (e.g., baby and water bottles) and line the inside of food and beverage cans, including infant formula cans. On the inside of a tin, it’s role is to protect the food or drink from coming in contact with the metal of the can and to extend its shelf life. It is also found in plastic tableware.
It is detectable at biologically active levels in the urine of an estimated 93% of Americans and can leach into the food when the plastic containers are heated in a microwave or washed in a dishwasher.
Importantly, BPA can leach from plastic bottles into the water itself. Storing or carrying water in stainless steel, glass or BPA and phthalate free containers will reduce exposure to endocrine-disrupting chemicals.
Since public awareness of the concern of BPA has increased, manufacturers have switched to other chemicals to harden plastics. Consumers should be aware that the safety of these substitutes is unknown and people should refrain from any exposure where possible.
What are the health impact of BPA?
Much remains to be learnt about the effects of environmental exposures on cancer risk, however, there is strong correlating evidence to associate BPA as an endocrine (hormone) disruptor and has been known to disrupt oestrogen receptors since the 1930’s. As a group, endocrine disrupting chemicals (EDCs), BPA has received the most public attention, however, other inclusions should also be avoided.
BPA disrupts the endocrine system because it acts as a weak oestrogen. Over the past decade, there have been more than 130 studies linking BPA to breast cancer, obesity and other serious medical problems and disorders. In 2007 a group of independent NIH (national institute of health) funded investigators concluded that there was a strong cause for concern that exposure could result in cancer and early puberty. The Center for the Evaluation of Risks to Human Reproduction concluded in 2008 that there is “…some concern for effects on the brain, behaviour, and prostate gland in foetuses, infants, and children at current human exposures to bisphenol A.”
Additionally in 2008, there was a study that found that adults with a higher urinary BPA level had levels of heart disease, diabetes, and liver abnormalities. Other studies also suggest that BPA may interfere with cancer treatments.
What about phthalates?
Like BPA, phthalates disrupt normal hormone function by mimicking estrogen. This group of chemicals is used to make plastics soft and pliable. They are found in a wide array of consumer products, including plastic bottles, IV tubing, toys (including soft teething toys for babies), cosmetics, hair conditioners, and fragrances. Phthalates inhibit normal binding to estrogen receptors and suppress male androgens. In girls, phthalates may cause early puberty and higher breast cancer risk later in life. Male foetuses in the first trimester of pregnancy appear to be particularly vulnerable to damage by phthalates, which may cause undescended testicles, hypospadias, and possibly higher testicular cancer risk. In humans, phthalates have been linked to problems with sperm count and sperm quality, and like other EDCs, phthalates are a suspected breast carcinogen. The biggest researchers in this area are a group of Danish researchers who in 2001 reviewed 15,000 men from 21 countries, and discovered an alarming plunge of nearly 50% in average sperm counts over the past half-century. The book ‘our stolen future’ discusses these concerning risks and correlates these declining fertility statistics specifically in males with the emergence of increased environmental exposures to EDCs including phthalates and BPA.
Why are BPA products in Australia not banned?
European, Canadian, American, Australian and New Zealand (FSANZ) authorities have established a safe level (tolerable daily uptake) as 0.05 mg per kg bodyweight per day.
As of July 2010, Australian authorities have initiated a voluntary phase out of the use of BPA in polycarbonate baby feeding bottles whilst Canada, Denmark, France and several states in the USA have banned BPA from baby feeding bottles. Canada has banned since 2008.
FSANZ commissioned a survey to assess BPA content in Australian foods and concluded that there were no detectable levels found in infant formula, tap water, infant feeding bottles and sip cups in Australia, however, there were levels in canned foods predominantly. Some of the highest readings were found in canned infant dessert and canned tuna in oil. Also note that BPA levels regarding infant feeding bottles is not listed in their published data and breast milk in bottles was not assessed – important difference as breast milk contains a high percentage of fat. However, a recent CHOICE survey did detect levels in all of the recently outlined substances. FSANZ admits, though that data in Australian foods is limited and evidence needs to be enhanced.
People should be alerted that whilst Australia and New Zealand are in a ‘voluntary phase out’ due to concerns with BPA that the phase out does not adequately protect the public from the risk. People should avoid all exposure.
If BPA was banned in Australia, how long would it take for the risk from prior BPA exposure to start to diminish?
Endocrine disruptors – especially oestrogen disruptors love to reside in our adipose (fatty) tissue and love the fat portion of food substances (hence why tinned tuna showed some of the highest levels). BPA resides both in food substances but is also biologically available in our water supply. As such, a specific time would be difficult to ascertain due to a number of considerations required. Calculating the half-life of a substance is highly individual and reflects each person’s metabolism. One paper tried to assess if fasting influenced the clearance of BPA to determine accurate clearance time. These researchers found that the overall half life for the population for the 0- to 24-hr interval was 43 hr, however, BPA levels did not decline rapidly with fasting time. This suggested that other variables influenced including substantial nonfood exposure, accumulation in body tissues such as fat, or both.
Until we know more about any human health risks, avoid plastics containing BPA and generally avoid plastic products as much as possible. Never wash plastics in the dishwasher and avoid heating them in microwaves if you have to use them. Reduce your consumption of foods stored in cans and avoid food storage solutions such as cling wrap and other plastic containers. Finally, go and buy a stainless steel bottle and reduce how much water you drink from plastic bottles. Above all, never let your water bottle heat (i.e. leaving it in the car) as the plastics will leach the BPA into the water…