The more and more I think and write about food, the more I put my pantry shelves to scrutiny. While the ultimate goal is to reduce any reliance on ‘processed food’, one food product that makes a regular appearance in my kitchen is canned tomatoes. They are an essential during the winter months when fresh tomatoes taste like cardboard and can transform winter stews and soups. Aside from canned foods coming with a hefty transportation induced carbon footprint, there is the effects of BPA on the environment (and our health) to consider. If you are not lucky enough to have jars of preserved tomatoes from your summer garden harvest, the BPA in the cans lining could be doing damage. But what is BPA? What are the healthy and environmental concerns?
What Is BPA?
Bisphenol A (BPA) is a synthetic compound used to make polycarbonate plastic food storage containers, water and baby bottles. It is prized for its ability to make hard, clear plastics. It is also found in epoxy resins that protect the metal linings of food and drink cans such as canned tomatoes, canned soup and sodas from degradation which can occur when metal contacts food. BPA is found all around us in our environment and both environmental and food sources contribute to our overall exposure to this chemical.
What Does BPA Exposure Mean For Our Health
In 2010 it was found that 91% of Canadians have BPA in their bodies. This number is similar to that of 95% of Americans aged 6 and up and 99% of Germans aged 3-14.
Health Canada has set a tolerable upper limit (TUL) of BPA consumption to 25ug/kg of bodyweight per day which has been criticised by many researchers. New evidence shows that even low doses of BPA can have endocrine disrupting effects, meaning BPA can imitate our body’s own hormones in a way that could be hazardous to health. Humans in a stage of rapid development such as childhood or in the womb tend to be especially sensitive to the endocrine disrupting effects of BPA.
Ethical constraints mean BPA cannot be tested in human trials. Some animal studies have demonstrated the effects of BPA at or below the upper limit of BPA set by Health Canada and have found disturbing results;
- Decreased plasma testosterone in males,
- Decreased sperm count and fertility in males,
- Stimulation of mammary gland development in female offspring,
- Altered immune function,
- Behavioural changes, including hyperactivity and increased hostility.
BPA Banned in Baby Bottles
In 2008 the Government of Canada banned BPA in baby bottles*. This was found to be the main source of BPA for this age group, especially when hot or boiling liquids were added to the bottles. The European Union followed suite and has also issued a ban on BPA in baby bottles. Not long after, the United States FDA also removed the use of BPA in baby bottles, sippy cups and infant formula packaging. Their choice to remove this chemical was more based on market abandonment rather than safety concerns.
Australia has been left behind in the abandonment of BPA baby bottles. Food Standards Australia New Zealand (FSANZ) states there are no health risk related to BPA baby bottles if the manufacturer’s instructions are followed. They suggests the use of glass baby bottles if parents have any concerns. The Australian Government has recently introduced a voluntary phase out of BPA use in polycarbonate baby bottles.
*The Canadian Government has still not removed BPA from infant formula. See here from more info.
BPA and The Environmental Consequences
BPA is a persistent compound that does not degrade in the environment. It can have seriously detrimental effects on aquatic life including the reproduction and development of fish, aquatic invertebrates, reptiles and amphibians. BPA is also a major soil pollutant which can interfere with nitrogen fixation at the roots of several types of plants.
In 2010, the Government of Canada announced that BPA was to be added to Schedule 1 of Canadian Environmental Protection Act indicating the chemical was potentially harmful to human health and the environment. Along with addressing the release of BPA through industrial effluent, ongoing research is going into releases of BPA that could occur during the disposal or recycling of products.
Update January 2014: EU Findings on BPA and Human Health
In January 2014 the European Food Safety Authority (EFSA) released a draft reviewing the effects of exposure to both food and environmental sources of BPA. They identified adverse effects on the liver and kidney and effects on the mammary gland linked to exposure to BPA. The EFSA has since lowered their current upper limit of 50ug per kg of bodyweight to 5ug per kg of bodyweight*.
What You Should Know About BPA
The more informed we are, the better equipped we will be to make the decisions that will influence our exposure to BPA in our day-to-day life. As ongoing research continues, I would prefer to play it on the safe side rather than expose myself to large amounts of potentially harmful substances. Here is some more information to help keep you well informed.
What is the BPA Content Of Some Common Foods
- 220 g canned baked beans in tomato sauce (3.1 µg BPA),
- 100 g canned ham (42.2 µg BPA),
- 250 mL canned tomato soup (2.5 µg BPA),
- 1 small can of tuna (120 g drained) (5.7 µg BPA)
- 125 mL canned fruit (4.8 µg BPA)
- 2 L of water (2 µg BPA)
- 1L canned soda or energy drink (0.1-4.5 µg BPA)
- 1L canned beer (0.08-0.54 µg)
Based on the EUs temporary upper limit a 70kg (154 lbs) person shouldn’t be exposed to any more than 350 µg BPA per day. Health Canada recommends a maximum of 1750 µg BPA per day.
A recent 2012 assessment of Canadians intake of food products exposed to BPA indicates Canadians consumption is within the acceptable range. See here for a full assessment, including the BPA content of other food products.
The Environmental Working Group has an excellent assessment of a variety of canned foods and their BPA content. See the full report here.
Factors That Effect the Leaching of BPA From Food Containers To Food
- Elevated temperatures (boiling over 100 degrees C),
- Caffeine content of the food; caffeine increases migration of BPA to the food,
- Fat content of the food; fat appears to decrease migration of BPA to food,
- Prolonged usage of the container;
- Reheating foods; only use containers labels as heat and microwave-safe, or non-BPA containers, such as glass for microwaving purposes.
Environmental Sources Contributing to Our BPA Exposure
Food is the main source of BPA for consumers but environmental sources are also a concern. Thermal paper accounts for 15% total human BPA exposure. BPA exposure can also come from a variety of other environmental sources:
- Epoxy resins used in food-processing applications, ie the coating applied to the interior surfaces of some vats used in wine making,
- Epoxy resins in epoxy resin-based paints, floorings, adhesives and protective coatings. Similar resins are also used in some dental composites and sealants,
- Epoxy resins in thermal paper used for sales receipts, movie tickets, airlines tickets,
- Epoxy resin lined water pipes,
- Water contamination from BPA leaching from landfills into the soil and the runoff from paper mills.
BPA All Around Us
BPA can be found all around us in our industrial world. These sources don’t necessary contribute to human exposure, but they sure do contribute to environmental contamination.
- Epoxy resins in surf boards,
- DVDs and CDs,
- Eyeglass lenses,
- Household electronics,
- Sports equipment,
- Sheets for roofing,
- Greenhouse glazing,
- Glazing for bus stop shelters,
- Safety goggles,
- Contact lens holders,
- Collapsible tubes (toothpaste, cream).
BPA-Free Alternatives and Living BPA Free
There continues to be a lot of uncertainty surrounding BPA-free alternatives with some speculation that BPS may have similar effects as BPA. Safer options will be to opt for glass in place of plastic, or chose fresh fruits and vegetables over canned. Oleoresins can be used in place of BPA in canned products and is a natural mixture of an oil and a resin extracted from plants such as pine or balsam fir. Eden Foods uses oleoresin for its canned bean products. More research is needed in the area. In the mean time I am switching my canned tomatoes to tomatoes in glass jars.
Limit hard plastic bottles (#7 plastic) which can leach BPA into water. Carry stainless steel or other BPA-free bottles. Don’t reuse bottled water bottles. The plastic can harbor bacteria and break down to release plastics chemicals.
David Suzuki: 12 Ways To Avoid BPA
Environmental Working Group: BPA in Canned Foods
Environment of Canada:Government of Canada Takes Further Action on BPA
European Foods Safety Authority: Bisphenol A
Health Canada: Updated Assessment of BPA Exposure From Food Sources
PEN Nutrition: Food Safety – Bisphenol A Practice Guidance Summary