The latest study on BPA health effects
ScienceDaily (June 6, 2011) reported on a study being presented at The Endocrine Society’s 93rd Annual Meeting in Boston about how daily exposure to Bisphenol A (BPA) – a compound prevalent in our modern society – causes lowered fertility in male mice.
Continued exposure to BPA affects male fertility by lowering sperm count and levels of testosterone. Surya Singh, PhD (and the study’s principal author) states “We are being exposed to BPA in our daily lives at a level much higher than the safe recommended exposure”.
The effects of BPA have been questioned for a while, with an increasing number of studies showing that BPA, an endocrine (hormone) disrupter, has been linked to breast cancer, infertility and early puberty, so this is not simply a male fertility issue.
Science Daily states that common sources of BPA exposure are epoxy resin-lined food cans and hard polycarbonate plastics, which leach the chemical, especially when heated to high temperatures.
How to minimize BPA Exposure
This article got me thinking, so I had a look for other sources of BPA. A 2008 study by Lang et al* reveals that most BPA exposure is through diet, but can also occur through inhalation and skin absorption.
The EPA considers exposures up to 50 µg per kg per day to be safe, but sensitive animals may show effects at lower doses. Another interesting bit of information is that, according to Stahlhut**, BPA can be stored in the body, for example in the fat cells.
SO, how can you minimise your exposure to this toxic compound?
- Eat fresh foods wherever possible
- Look out for BPA free plastics and avoid plastic with the recycling category 7 (This is the ‘other’ category, so some will have BPA, and some won’t).
- Don’t wash plastic in the dishwasher, or put it in the microwave.
- If you use plastic containers to store food, wait until your food has cooled completely before putting it in the container.
- Avoid contact with till slips, where the BPA is ‘free’ (it’s used in the coating, and much more likely to be absorbed through contact). Don’t keep these in your wallets & bags, either, as the BPA powder rubs off onto whatever it touches – in most cases, money. (which means that the money you handle is likely contaminated as well).
- Check your pipes (the household kind) – some of the older water pipes have epoxy resin coating, which contains BPA.
Sources of BPA
It is important to make a note here that, although it is easy enough to find the ‘safe’ limit of BPA (according to the EPA), it is a lot more difficult to get a definitive idea of what sources expose us to what amounts of BPA. I included quantities where possible, but have used conservative figures – the quantity of BPA to which you’re exposed is affected by many factors, such as length of time of exposure (i.e. holding a till slip vs touching & disposing), washing methods, heat, age of item, wear & tear, etc.
- Tins & Cans (food & soda) – the process of canning involves high heats (and sometimes acidic foods), which causes the plastic lining of the tins to leach BPA. (Note – Eden Foods (Michigan) uses enamel lining in their cans, which is BPA free).
- Plastic containers – Avoid polycarbonate (hard plastic) packaging , especially that with the recycling number 7 (which is non-recyclable, anyway), although some plastic with numbers 1,2 & 5 have shown levels of BPA as well.
- Check your water bottles to make sure that they’re BPA free. Even though you might not heat these, harsh detergents and prolonged use can also cause BPA to be released. Drinking from polycarbonate bottles almost doubles the BPA urine level (i.e. what is absorbed and released) from 1.2 μg to 2 μg per gram creatinine. (The Wikipedia reference does not state how much you have to drink to achieve this, nor whether this is increased as the bottle ages (and the plastic wears down).
- Thermal paper & carbonless copy paper (this includes most receipts & tickets) – touching these releases roughly 1 μg BPA (0.2 – 6 μg) was transferred to the forefinger and the middle finger, and 10x more if your fingers are sticky or greasy!!
- BPA is also used to form epoxy resin coating of water pipes. In older buildings, such resin coatings are used to avoid replacement of deteriorating hot and cold water pipes
With the ‘safe limit’ of BPA being listed at 50 micrograms per kilogram, how do we know how much we are ingesting without an easily accessible and reliable resource for quantified exposure? How do we know what levels of BPA are being stored in our bodies, according to our exposure? Without cutting out the main culprits and putting pressure on the suppliers to find suitable alternatives to BPA-contaminated containers and receipts, or at least to quantify exposure so that we are more aware, we are gambling with our health.
* Lang IA Galloway TS, Scarlett A, Henley WE, Depledge M, Wallace, Robert B, Melzer, D (2008). “Association of Urinary Bisphenol A Concentration With Medical Disorders and Laboratory Abnormalities in Adults”. JAMA 300 (11): 1303–10. doi:10.1001/jama.300.11.1303. PMID 18799442.
**Stahlhut RW, Welshons WV, Swan SH 2009. Bisphenol A Data in NHANES Suggest Longer than Expected Half-Life, Substantial Nonfood Exposure, or Both. Environ Health Perspect 117:784-789. doi:10.1289/ehp.0800376