The plastic monomer bisphenol A is often used in materials with food contact and is suspected of being an endocrine disruptor. But it can be replaced by less hazardous substances.
By Susanne Bruun Jakobsen and Vibeke Ærø Hansen, The Ecological Council
Bispenol A (BPA) is a chemical substance often integrated in impact-resistant plastics and surface coatings in canned foods as well as screw-on caps and cashier receipts. The compound has a widespread use in materials with food contact, which leaves consumers at great risk for exposure and consumption of the substance without their knowledge, and without much opportunity to avoid such exposure. BPA has known endocrine disrupting effects and is suspected to be a contributing factor in disorders such as overweight, diabetes, cardiovascular diseases, behavioral changes in children, etc.
The European Food Safety Authority EFSA has set a limit of 50 μg/kg body weight per day for a tolerable daily intake of BPA. There has been much discussion about whether, and to what extent, BPA has a harmful effect, when consumed in quantities below that limit. The conclusions about BPA’s health effects seem to depend on how the underlying studies are structured. Several hundred studies conducted at different independent research institutions mostly indicate that exposure to BPA is problematic. Conversely, a few large industrially funded studies, concludes that there is no significant risk.
In March 2010 Denmark chose to employ the EU’s precautionary principle in relation to BPA in early childhood products. The precautionary principle can be put into use in situations where preliminary studies show dangers to human health, but where the evidence available does not allow a full risk assessment, for example because of discrepancies between existing data. This is precisely the case with BPA, and the reason why Denmark for the time being has prohibited BPA in all packaging materials used in food products intended for children aged 0-3 years.
EU ban on BPA in baby bottles
EFSA completed another assessment of BPA in September 2010. Once again the authority decided to retain the existing limit of tolerable daily intake, because the data available did not provide evidence enough to change the limit. It was noted however, that further investigation is needed since not all studies acquit BPA. Despite this, the Danish Minister for Food at the time, Henrik Høegh maintained the Danish temporary national ban on BPA. In October 2010, the EU Health Commissioner spoke for reducing children’s exposure to BPA due to uncertainties in new studies, and in November the EU decided to ban the use of BPA in baby bottles for infants below 12 months. The proposal had strong support among member states and prohibits the production of BPA-containing baby bottles from March 2011 and bans import and sale in the EU from June 2011.
Canada was first with BPA-free baby bottles
Uncertainty and disagreement about BPA’s adverse affect on human health has made many consumers worried. Especially parents of babies and young children are vigilant towards BPA in baby bottles and packaging for baby food.
Already in the middle of 2008 the Canadian government announced that it would ban the import, sale and advertising of BPA-containing baby bottles, thus forcing Canadian manufacturers to find and use alternative materials for baby bottles. As a result there are virtually no polycarbonate baby bottles in Canada today. In the USA concern and pressure from consumers caused Wal-Mart and Toys “R” Us to follow the Whole Foods Market (the first Canadian retailer to ban BPA-containing polycarbonate baby bottles and child cups in January 2006) example and announced that they would stop selling baby bottles containing BPA. In March 2009 the six major American baby bottle manufacturers proclaimed that they would phase out use of BPA in bottles sold in the USA, but they still have no ban. (1)
Finding alternatives to BPA – hard but important
Developing alternatives to BPA is very important. Not just for baby bottles, but also for drinking bottles, food cans and screw-cap coatings. Several manufacturers outside of Denmark have shown that it is possible to find alternatives to BPA even before any legislation has forced them to substitute BPA in their products. These companies have been driven by their idealism, by corporate social responsibility (CSR) or by pressure from consumers. With time the producers and distributors that take the consumers’ concern for BPA seriously, before everyone else, may eventually benefit because no time is wasted in finding replacements and market shares are kept.
Because BPA is used in so many different contexts, it is not realistic to find just one alternative. Manufacturers of plastic bottles have been quicker at finding alternatives than other users of BPA. Some clear hard plastic bottles are now substituted with polyamide, for example baby bottles from Born Free, or with Tritan copolyester as in drinking bottles from Nalgene (1). In 2008 Nalgene announced that they voluntarily would phase out the use of polycarbonate containing BPA. They manufacture consumer bottles and containers in HDPE, PP, LDPE, PET, and Eastman Tritan copolyester and Stainless Steel (by Guyot Design). Each of these materials is manufactured without BPA.
Conversely, it has proved harder to find replacements for the coating used inside of beer, soda and food cans as well as metal lids. One reason the coating is needed is to prevent metal leaking into the food or drink in the can. Danish companies have shown interest in developing BPA-free alternatives, but have not succeeded yet. It can take up to 10 years to develop and test a new coating, a report from the Danish Environmental Protection Agency estimated in 2004. They found that the alternative polyester-based coatings were less durable and less usable and thus more costly (2).
Alternative coatings for cans
Outside of Denmark however, alternative materials replacing BPA in soda cans and other canned products are used in numerous places. For example in Japan where manufacturers in the 1990’s voluntarily began to apply a polyester coating and only use BPA when it was necessary as underlying adhesive. This decision reduced the content of BPA in food and beverages significantly (1). In the U.S., the manufacturer of Eden Organic Beans have utilized cans with a coating made from a mixture of plant-based oil and resin since 1999. This voluntary praxis has resulted in an additional cost of 14% for the cans. Tomatoes are not put in the BPA-free cans, as it is not yet approved for this purpose (3).
Some years ago Green Century Capital Management, which advises on environmentally friendly investments, made inquiries among 20 major food producers in the U.S about their use of BPA in food product packaging. Hereof 14 chose to answer and four expressed interest in making an effort to find replacements. One of the four companies, Hain Celestial, launched a BPA-free container for breast milk substitute in March 2009 and continuously develops and test new coatings, because the company is very focused on finding BPA-free packaging for baby food. Likewise, Heinz no longer uses BPA in cans containing baby food and wish to remove the substance from lids on glass containers used for baby food in England. The company has also been involved in research and hope to remove BPA-containing paint from all other cans as well. Finally Nestlé has launched several projects to find alternatives to BPA (1, 4).
An alternative to BPA based on isosorbide produced from cornstarch has been developed by collaboration between Michael Jaffe, from New Jersey’s Science & Technology University (NJIT) and the Iowa Corn Promotion Board (ICPB). In the form of isosorbide-containing epoxy resin, this alternative product can replace BPA in the coating on the inside of canned foods. Cornstarch is used because corn is both cheap and readily available in the U.S., but other sugar-containing materials can also function as raw material. The further development of this BPA alternative will be carried out in collaboration with food packaging manufacturers, and possibly reach the market within a few years. (5, 6, 7)
Plastic containers may be marked with recycling labels indicating what material they are made of. Containers marked with a Seven may contain BPA, but not necessarily. The labeling scheme is voluntary.
BPA in non-food products
In addition to the food industry, BPA is used in completely different types of products such as thermal paper for till receipts, sports equipment, medical equipment, CDs, and electronics. The Danish Environmental Protection Agency has launched a survey of till receipts on the Danish market to assess whether they may pose a risk to consumers. Uptake from sources other than oral intake or for example through the skin is not the EFSA’s area. But these issues may prove relevant in relation to cash register receipts and many other products containing BPA. In those cases it is the European Unions chemical legislation called REACH that should be employed. If Member States are concerned about BPA’s effects in nonfood products, they may propose to add the BPA on the candidate list of particularly hazardous substances.
Until the law is tightened in respect to BPA, or manufacturers and retailers respond to consumer demands, the individual consumer must find his own way around BPA. The best way is to avoid cans, bottles and containers for food storage made of polycarbonate plastic. However, it can be difficult to completely avoid canned foods, but you can minimize the use.
Can the alternatives be just as dangerous?
When alternatives are developed they also have to be tested for any possible health and environmental risks. Despite this, it cannot be ruled out that future problems might occur with these materials too. But as in the case with the cornstarch alternative mentioned above, it seems highly unlikely that the alternative has properties as dangerous as BPA does. Nevertheless, any alternative substances must always be thoroughly tested, before they are put into use, regardless of whether they are produced from naturally occurring materials or industrially.
Applications of BPA
BPA is a monomer, which forms the basis for the production of polycarbonate, better known as shockproof plastic. Polycarbonate is used in a wide range of products such as skylights, cabinets for electrical appliances, CDs, eyeglass lenses, medical equipment, baby bottles and containers for food storage.
In addition, BPA is a component in epoxy lacquer used for protective coatings inside metal cans (canned) and screw caps, in order to avoid leakage of metal from the can into the food and beverages. BPA can also be found in different types of thermal paper such as till receipts and fax paper.
• BPA is believed to be absorbed primarily through food items and has an estrogenic-like effect.
• In population surveys BPA was found in large percentages of the population.
• BPA has been detected in various types of tissues and fluids in the human body, including urine, blood, adipose tissue, placenta, umbilical cord, amniotic fluid and breast milk.
• Based on animal and cell studies, as well as more recent population studies, BPA has been linked to a number of adverse health effects, such as reproductive problems, cancer, obesity, type 2 diabetes, cardiovascular diseases and behavioral and learning difficulties in children.
1) Ruoff L. & Stone E. (2009). Seeking safer packaging. Ranking packaged food companies on BPA. Green Century Capital Management & As You Sow.http://www.greencentury.com/pdf/globaldocuments/Seeking_Safer_Packaging.pdf
2) Møller L., Helweg C., Pratt C.H., Worup A. & Skak C. (2004). Evaluation of Alternatives for Compounds under Risk Assessment in the EU, Bisphenol A. Environmental Project No. 901, Miljøstyrelsen.
3) Eden Foods (2010) http://www.edenfoods.com/articles/view.php?articles_id=178
4) Hain Celestian on BPA. Sacramento Natural Foods Coop, 2010
5) Ariel Schwartz: Coming Soon: A Corn-Based BPA Replacement, Mon Aug 16, 2010 http://www.fastcompany.com/1682423/coming-soon-a-corn-based-bpa-replacement
6) Rory Harrington: Suger-derived epoxy lining could replace bisphenol A, Foodproductiondaily.com 04-Mar-2010http://www.foodproductiondaily.com/Packaging/Sugar-derived-epoxy-lining-could-replace-bisphenol-A
7) Press Release NEWARK, Feb 24 2010: NJIT Patent May Be Able To Replace BPA; Make Consumer Products Safer http://www.njit.edu/news/2010/2010-053.php
Literature – Health effects from BPA
Sattler B., Afzal B. & Baier-Anderson C. (2010). Report on public health concerns – phthalates and bisphenol A.
To Public Health Subcommittee, Health and Government Operations Committee of the Maryland General Assembly.
Reduced sperm production/fertility in male rats.
Sugiura-Ogasawara et al. (2005). Exposure to bisphenol A is associated with recurrent miscarriage.
Human Reproduction vol. 20 p. 2325-2329.
Recurrent spontaneous abortions in women (smaller study, 45 women + control group).
Newbold R.R., Jefferson W.N. & Padilla-Banks E. (2009). Prenatal exposure to bisphenol A at environmental relevant doses adversely affects the murine female reproductive tract later in life. Environmental Health Perspectives vol. 117 p. 879-895.
Abnormal conditions of the ovaries, fallopian tubes and adenoids in the uterus of female mice, conditions, which can be precursors to cancer.
Sattler B., Afzal B. & Baier-Anderson C. (2010). Like fertility reference 1.
Stimulation of breast tissue development in mature female offspring of rats can result in increased susceptibility towards estrogen and cancerous chemicals. Among male offspring of rats enlarged prostate and increased probability of prostate cancer later in life is seen.
3. Behavior and learning abilities
Braun J.M., Yolton K., Dietrich K.N., Hornung R., Ye X. Calafat A.M. & Lanphear B.P. (2009). Prenatal bisphenol A exposure and early childhood behavior.
Environmental Health Perspectives vol. 117 p. 1945-1952.
Study including 249 pregnant women. BPA content in urine linked to more aggressive and outward-rushing behavior especially amongst girls at the age of two.
4. Diabetes, overweight and cardiovascular disease
Lang I.A., Galloway T.S., Scarlett A., Henley W.E., Depledge M., Wallace R.B. & Melzer D. (2008). Association of Urinary Bisphenol A Concentration With Medical Disorders and Laboratory Abnormalities in Adults.
JAMA vol. 300 p. 1303-1310.
Higher concentration of BPA in urine of 1.455 Americans was associated with an increased occurrence of diagnosed type 2- diabetes and cardiovascular disease, such as reduced blood supply to the heart, heart attacks and cardio spasm.
Alonso-Magdalena P., Vieira E., Soriano S., Menes L., Burks D., Quesada I. et al. (2010).
Bisphenol-A Exposure during Pregnancy Disrupts Glucose Homeostasis in Mothers and Adult Male Offspring.
Environmental Health Perspectives vol. 118 p. 1243-1250.
In pregnant mice, BPA can contribute to the development of diabetes and overweight during pregnancy and dispose for diabetes later in life. Male offspring showed a reduced glucose tolerance and increased insulin resistance that may predispose for diabetes later in life also in humans