What’s the sense in drinking purified water or eating organic food if you use the wrong kind of plastic bottle or container?
When I was studying to be a dietitian, I and my fellow students used to pack leftovers for lunch in little plastic containers so that we didn’t have to eat fast food on campus. We also carted around plastic bottles of water so we had access to clean drinking water all day. We took these actions because preventive health and food safety were important to us, which is probably why we all went into this field to begin with!
Fast-forward to 2009 and all the recent media reports and controversy surrounding the safety of plastic bottles and containers. If nutritionists are confused about the legitimacy of these reports, what exactly is a health-conscious consumer supposed to do?
Here’s the real scoop on plastic product safety so you and your clients can make informed decisions.
In April 2008, the federal National Toxicology Program (NTP) issued a brief addressing the safety of bisphenol A (BPA), the main chemical found in polycarbonate plastic. In their conclusion, the NTP reported that “there is some concern for neural and behavioral effects in fetuses, infants, and children at current human exposures, [and there is] some concern for bisphenol A exposure in these populations based on effects in the prostate gland, mammary gland, and an earlier age for puberty in females” (NTP 2008). Environmental and consumer safety groups have raised similar concerns, because BPA has been linked to the production of the hormone estrogen in humans and shown to be harmful in animal studies.
All this talk led to a national media frenzy that has raised awareness and fueled mounting concern about the safety of plastics and our food and beverage supply. Moving beyond food, there is additional concern about the role of plastic additives, such as phthalates, in the manufacture of toys, drug capsules, cosmetics and hundreds of other everyday products.
The ubiquitous use of plastic makes it hard to imagine a day without exposure. Plastics are used in the automotive, building and construction, electrical, packaging, medical and consumer products industries. There’s no question that the discovery and widespread utilization of plastics has made our lives easier. Can you imagine toting a water bottle to the gym if glass containers were your only option? Yet one must question whether our lives have been made safer, particularly from a preventive health and disease perspective.
BPA is a chemical employed primarily in the production of epoxy resins and certain hard plastics collectively called polycarbonates. Polycarbonate plastics are used to make a multitude of products, including (but certainly not limited to) water and infant bottles, tableware, food containers, compact disks, impact-resistant safety equipment and medical devices. Epoxy resins are used as lacquers to coat metal products like food cans, bottle tops and water supply pipes, as well as being used in dental sealants or composites (NTP 2008). Polycarbonate is popular with manufacturers of water bottles and other plastic food and beverage containers because of its extraordinary durability, glass-like clarity, and resistance to stains and odors (U.S. Food and Drug Administration [FDA] 2008a; Nalgene 2008).
Even though BPA is broadly used, for most people the primary source of exposure to the chemical is through diet. BPA can migrate into food from polycarbonate food and beverage containers or from food and beverage containers that contain or are lined with epoxy resin.
According to the NTP brief, the migration of BPA from a plastic container into food depends more on the temperature of the food or liquid in question (e.g., if it is reheated in a microwave in a BPA-laced container) than on the age of the container itself (NTP 2008). However, at least one study disputes that finding (Howdeshell et al. 2003). Researchers tested samples of room temperature water that had been incubated in both new and used polycarbonate animal cages. Although estrogenic activity was detected in both new and used samples, the highest exposure levels were found in the older cages (Howdeshell et al. 2003). This result differs from the body of research on BPA leaching.
Human exposure to bisphenol A is generally detected and measured using blood, urine, breast milk and other fluid or tissue samples. The 2003–2004 National Health and Nutrition Examination Survey (NHANES) identified detectable levels of BPA in more than 90% of 2,517 urine samples from people 6 years and older (CDC 2008).
BPA Health Risks
In general, infants and children have the highest estimated daily intake of environmental chemicals because on a pound-for-pound basis they eat, drink and breathe more than adults. Young children are also more likely to ingest dirt and other particles as they crawl and play on the floor; chewing on plastic cups or other items potentially increases their exposure as well (NTP 2008).
A host of medical conditions are linked to BPA exposure, primarily because of the chemical’s estrogenic effects. One study showed changes in cellular function when even minimal concentrations of BPA were detected in bodily fluids (Welshons, Nagel & vom Saal 2006).
Additionally, BPA works on the biological system as an endocrine disruptor, a naturally occurring or man-made substance that interferes with natural hormone balance and function. Endocrine disruptors turn on, shut off or modify signals that hormones carry, which in turn affects the normal functions of tissues and organs throughout the body.
BPA can cause profound changes in the body, especially in unborn fetuses, infants and children. Examples of these effects include
- neural and behavioral changes;
- early puberty in both males and females;
- altered prostate and urinary development in infant males;
- a variety of cancers; and
- increased waist circumference and body mass index (BMI) (NTP 2008; Hatch et al. 2008).
Phthalates are a group of chemicals used to make hundreds of products, including toys, vinyl flooring and wall covering, shower curtains, detergents, lubricating oils, food packaging (e.g., some plastic wraps), pharmaceuticals and medical supplies, and personal care products such as nail polish, hair spray, soap and shampoo. Phthalates make vinyl and other plastics soft and pliable; make nail polish chip resistant; and slow the evaporation of perfume fragrances, allowing the scent to linger longer (FDA 2008b).
The FDA and the American Chemistry Council have stated that phthalates are safe for humans and/or that the data is unclear (FDA 2008b). However, many readily accessible studies support an opposite view. Animal and human studies show that phthalates, like BPA, act as endocrine disruptors (Stahlhut et al. 2007).
It is essential to note that Europe has banned phthalates from use in certain toys and personal care products. New European chemical legislation was created in 2007 to significantly improve protection of human health and the environment.
Phthalate Health Risks
Despite reassurances from the FDA and the U.S. chemical industry, there are findings that show a link between phthalates and health risks. One study concluded that concentrations of several prevalent phthalate metabolites showed statistically significant correlations with abdominal obesity and insulin resistance (Stahlhut et al. 2007).
A recent cross-sectional study analyzed the associations between six phthalate metabolites and BMI and waist circumference (WC) in participants aged 6–80 (Hatch et al. 2008). The researchers found increases in BMI and WC in some males when exposed to one particular phthalate, with similar associations identified in girls and women (Hatch et al. 2008).
Despite the findings in the NTP brief, and amid ongoing health safety concerns from the nation’s top scientists, consumer groups and politicians, last August FDA scientists concluded that the trace amounts of BPA that leach out of food containers are not a threat to infants or adults (FDA 2008c).
As of this writing, the FDA defends its ruling on BPA, insisting that the chemical does not pose a risk to the general population, young children included. However, many medical experts and scientific researchers dispute the FDA findings. For example, a recent study in the esteemed Journal of the American Medical Association found that high urinary concentrations of BPA were associated with increased risk of cardiovascular disease, diabetes and liver problems (Lang et al. 2008).
While the jury is still out on plastic-product health risks, you and your clients can remain safe by following the simple tips outlined in the sidebar “What Should a Consumer Do to Stay Safe?” n