The truth is, there’s no escaping plastics. We drink water from plastic bottles. We cook with plastics. We eat food from plastics. We’re even surrounded by people who are “plastic” — but that’s another story. Plastics have become an inevitable part of living — yes, like death and the Bureau of Internal Revenue.
We’ve been warned against false e-mail warnings re plastic bottles exposing us to cancer-causing dioxins. According to Rolf Halden, PhD, assistant professor in the Department of Environmental Health Sciences and the Center for Water and Health at the Johns Hopkins Bloomberg School of Public Health, one hoax e-mail has been attributed to Johns Hopkins University. To set the record straight, the Office of Communications and Public Affairs (Tim Parsons/Kenna Lowe) sat down with Halden and asked him some very absorbing questions, to which he gave equally absorbing answers. Here are excerpts from the Q & A:
What do you make of this e-mail warning that dioxins can be released by freezing water in plastic bottles?
ROLF HALDEN: No, this is an urban legend. There are no dioxins in plastics. In addition, freezing actually works against the release of chemicals. Chemicals do not diffuse as readily in cold temperatures, which would limit chemical release if there were dioxins in plastic, and we don’t think there are.
So, it’s okay for people to drink out of plastic water bottles?
First, people should be more concerned about the quality of water they are drinking rather than the container it’s coming from. Many people do not feel comfortable drinking tap water, so they buy bottled water instead. The truth is that city water is much more highly regulated and monitored for quality. Bottled water is not. It can legally contain many things we would not tolerate in municipal drinking water.
Having said this, there’s another group of chemicals, called phthalates that are sometimes added to plastics to make them flexible and less brittle. Phthalates are environmental contaminants that can exhibit hormone-like behavior by acting as endocrine disruptors in humans and animals. If you heat up plastics, you could increase the leaching of phthalates from the containers into water and food.
What about cooking with plastics?
In general, whenever you heat something, you increase the likelihood of pulling chemicals out. Chemicals can be released from plastic packaging materials like the kinds used in some microwave meals. Some drinking straws say on the label “not for hot beverages.” Most people think the warning is because someone might be burned. If you put that straw into a boiling cup of hot coffee, you basically have a hot water extraction going on, where the chemicals in the straw are being extracted into your nice cup of coffee. We use the same process in the lab to extract chemicals from materials we want to analyze.
What are dioxins?
Dioxins are organic environmental pollutants sometimes referred to as the most toxic compounds made by mankind ... Exposure to dioxins can cause chloracne, a severe form of skin disease, as well as reproductive and developmental effects and, more importantly, liver damage and cancer.
Where do dioxins come from?
We always thought dioxins were man-made compounds produced inadvertently during the bleaching of pulp and manufacturing of pesticides like Agent Orange and other chlorinated aromatics. But dioxins in sediments from lakes and oceans predate these human activities. It is now generally accepted that among the principal sources of dioxins are various combustion processes, including natural events such as wild fires and even volcanic eruptions.
Today, the critical issue is the incineration of waste, particularly hospital waste, which contains a great deal of polyvinyl chloride and aromatic compounds that can serve as dioxin precursors. One study examined the burning of household trash in drums in the backyard. It turns out that these small burnings of debris can put out as much or more dioxins as a full-sized incinerator burning hundreds of tons of refuse per day. The incinerators are equipped with state-of-the-art emission controls that limit dioxin formation and their release into the environment, but the backyard trash burning does not. You set it ablaze and chemistry takes over. What happens next is that the dioxins are sent into the atmosphere where they become attached to particles and fall back to earth. Then they bind to, or are taken up by, fish and other animals, where they get concentrated and stored in fat before eventually ending up on our lunch and dinner plates. People are exposed to them mostly from eating meat and fish rich in fat. (So, heed this burning warning: Never ever burn trash in your backyard.)
Is there anything else you want to add?
Don’t be afraid of drinking water. It is very important to drink adequate amounts of water and, by the way, that’s in addition to all the coffee, beer, and other diuretics we love to consume. Unless you are drinking really bad water, you are more likely to suffer from the adverse effects of dehydration than from the minuscule amounts of chemical contaminants present in your water supply. Relatively speaking, the risk from exposure to microbial contaminants is much greater than that from chemicals.
And here’s one more uncomfortable fact. Each of us already carries a certain body burden of dioxins regardless of how and what we eat. If you look hard enough, you’ll find traces of dioxins in pretty much every place on earth. Paracelsus, the famous medieval alchemist, put it straight and simple: “It’s the dose that makes the poison.”
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The long and short of vegetable shortening
We got e-mail inquiring about vegetable shortening and how trans fat differs from saturated fat.
Here’s nutritionist Dr. Angel Respicio’s reply: “Vegetable oil does not have saturated fat. A vegetable shortening is a partially hydrogenated vegetable oil. Manufacturers are allowed to put trans fat=zero if the trans fat level per serving is 500 mg. or below. So, if it is labeled zero, assume it is 499 mg. Consuming 2,000 mg. of trans fat will skyrocket your stroke risk by 93 percent, according to Dr. Stampfer of Harvard. The three names of trans fats that you should look for therefore in the list of ingredients are: partially hydrogenated oil, vegetable shortening, and margarine. Avoid products with any of these ingredients as much as you can.”
Expert consultant Mary Enig, PhD compares saturated fat and trans fat in terms of their biological effects:
• Saturated fatty acids raise HDL cholesterol, the so-called good cholesterol, whereas trans fatty acids lower HDL cholesterol.
• Saturated fatty acids lower the blood levels of the atherogenic lipoprotein, whereas trans fatty acids raise the blood levels of lipoprotein.
• Saturated fatty acids conserve the good omega-3 fatty acids, whereas trans fatty acids cause the tissues to lose these omega-3 fatty acids.
• Saturated fatty acids do not inhibit insulin binding, whereas trans fatty acids do inhibit insulin binding.
• Saturated fatty acids do not increase C-reactive protein, but trans fatty acids do increase C-reactive protein, causing arterial inflammation.
• Saturated fatty acids are the normal fatty acids made by the body, and they do not interfere with enzyme functions, whereas trans fatty acids are not made by the body and they interfere with many enzyme functions such as delta-6-desaturase.
• Some saturated fatty acids are used by the body to fight viruses, bacteria, and protozoa, and they support the immune system, whereas trans fatty acids interfere with the function of the immune system.
With that, we hope you will now be able to separate fat from fiction.
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