Choosing and Using a Water Bottle.
Although research has shown that drinking specialist sports drinks or dilute fruit juices can under some circumstances boost performance, drinking water is still best for many sports and particularly in team sports. But what should you put your water in? and does it make a difference?
Are some water bottles better than others ?
Over the last couple of years there have been a range of stories in the media and on the internet about the risks of drinking from and reusing plastic water bottles. It has been widely reported that known carcinogens or endocrine disrupters that can leach into water from the bottle over time and that this may be sped up if the bottle is frozen, heated, or left in the sun.
COMMERCIAL BOTTLED WATER
Bottled water is regulated as a packaged food product and so must meet global standards (1). PET (polyethylene terephthalate), the plastic that is most often used to manufacture bottled water containers and DEHA (diethylhexladipate) which is used to produce PET, are considered to be safe “for food contact applications” and are thought to pose no risk to health (1). PET / PETE bottles can be identified as they are generally marked with recycling code 01.
Freezing water in PET bottles does not appear to be a risk, in fact freezing is thought to work against the release of any chemicals into bottled water (2). Heating PET plastics may pose more of a health risk, as it is more likely for chemicals to be released from plastics with heat than cold (2).
Reuse of PET plastic bottles is not recommended by commercial bottled water manufacturers, as they acknowledge it may pose a health risk. Everyday wear and tear from repeated washing and reuse can lead to physical breakdown of the plastic, such as invisible thinning or cracks. This may not only contaminate the water (7) but bacteria can harbor in the cracks and around the bottle neck or sports cap which can be a potential health risk. Reuse of plastic water bottles has been found to lead to bacterial contamination unless washed regularly. If you wish to reuse a plastic water bottle, manufacturers recommend it should be washed after each use in mild detergent only and rinsed well (3). The plastic should not be subjected to extreme, hot temperatures or harsh detergents, and should be carefully inspected for physical breakdown prior to reuse.
The recommended plastic for making sports drink bottles is low-density polyethylene (LDPE), marked 04 for recycling. However a quick search through our cupboards found bottles marked 02, (High-density polyethylene), 03, (Polyvinyl Chloride PVC) and 07 (Polycarbonate). This is pretty worrying, as it is generally accepted that the plastics you want to avoid for food items are numbers 3, 6, and 7 as they have been shown in studies to release chemical hormone disruptors or carcinogens into stored food or drink (4,5,6).
Code 03 Polyvinyl Chloride (PVC) includes di-2-ehtylhexyl phthalate (DEHP) which may leach into water. DEHP is an endocrine disruptor and a likely human carcinogen.
Code 06 Polystyrene (PS) can leach styrene – which is another possible endocrine disruptor and probable human carcinogen.
Code 07 Polycarbonate contains bisphenol-A, a the hormone disruptor. This chemical can leach out when it is heated or exposed to acidic solutions. This type of plastic was very common in sports bottles but has been largely phased out due to the risks.
As with commercially bottled water, there is also a risk of microbial contamination when reusing refillable water bottles without washing them properly and checking for evidence of visible wear and tear. Bacteria has been found to settle in the cracks and scratches and damage also increases the risk of chemicals leaching from the plastic during use.
I recommend that everyone should have a look at their water bottles particularly if they are old. There is still debate as to whether there really is risk from drinking water out of plastic bottles but I think perhaps how ever small its a risk not worth taking. Sports bottles marked with the recycling code 04 are generally acknowledged to be safest but they should be kept clean and replaced reasonably regularly. These LDPE bottles rarely taste of plastic, which I would take as a good sign. Reusing commercial PET or PETE water bottles (marked 01) is not advised by the manufacturers but the risk of chemical leakage is low, unless the bottle is damaged. All bottles should be cleaned well after use but not put into the dishwasher. I have thrown out my bottles marked 03 and 07.
1. International Bottled Water Association. IBWA Position Sum- mary: PET Plastic Bottled Water Containers and DEHA. Sep- tember 14, 2004. Available at: http://www.bottledwater.org/ public/IBWA_Position_Summary_PET_Containers_and_DEHA. html.
2. Johns Hopkins Bloomberg School of Public Health: Public Health News Center. Researcher Dispels Myth of Dioxins and Plastic Water Bottles. 2006. Available at: http://www. jhsph.edu/publichealthnews/articles/halden_dioxins.html
3. Whittelsey FC. Hazards of Hydration. Sierra Magazine November/December 2003. Available at: http://sierraclub.org/sierra/ 200311/lol5_printable.asp
4. Bisphenol A. Are Polycarbonate Bottles Safe for Use? New Information on an Old Scare Story. May 5, 2006. Available at: http://www.bisphenol-a.org/whatsNew/20060505.html
5. Specialty NEWS: Sierra Magazine Story Causes Stir Over Lexan Safety. November 12, 2003.
6. vom Saal FS, Hughes C. An Extensive New Literature Concerning Low-Dose Effects of Bisphenol A Shows the Need for a New Risk Assessment. Environmental Health Perspective, 2005; 113(8): 926-933.
7. Barrett. ENDOCRINE DISRUPTORS: Estrogens in a bottle. Environ Health Perspect. Jun 2009; 117(6): A241.