For scientists and physicians, the Internet has been both a blessing and a curse. Journal articles are at our fingertips and information about virtually any subject is just a few keystrokes away. But not all of the available information is reliable. A frightening amount of pseudo-scientific drivel permeates the web and spreads like wildfire when attached to emails. Either we are warned about some nasty chemical that is unraveling the very fabric of society, or we are alerted to the discovery of some miraculous natural healing agent that can cure virtually any disease.
The warnings often begin with the phrase “this is no joke,” and then continue with some ghastly revelation about the dangers of some substance in our daily life. Like plastic water bottles that leach a dangerous hormone called diethylhydroxylamine (DEHA) into their contents to make people feel younger and stimulate them to buy more bottled water. Where does the idea that bottled water is laced with hormones come from? The essence of the message is as follows: “the plastic used to make these bottles contains a potentially carcinogenic element (something called diethylhydroxylamine or DEHA)” which leaches out of the plastic on repeated washing and rinsing.” Consumers are then warned that such water bottles should not be refilled but be discarded after a single use.
The seed from which this story germinated can be traced to a scare circulating on the Internet about the migration of a chemical commonly referred to as DEHA into water from plastic water bottles. Of course, DEHA is not an “element,” it is a compound. And in any case, the author of this epic epistle has the wrong compound. Diethylhydroxylamine is indeed sometimes abbreviated as DEHA, but it has nothing to do with plastic water bottles. The chemical in question is diethylhexyladipate, commonly and perhaps confusingly, also abbreviated as DEHA. This is an approved plasticizer, a substance added to certain plastics to make them soft and pliable. Furthermore, neither of the “DEHAs” is classified as a carcinogen. But there is yet a further problem with the scare. While diethylhexyladipate is commonly used as an additive in certain plastics, it is not an ingredient in the polyester used to make water bottles! Polyester is innately flexible and does not require plasticizers.
So how did a compound that isn’t even present in plastic bottles trigger an alarm? The scare seems to have been spawned by an abstract of a talk given by a Master’s student from the University of Idaho at a scientific conference. Such abstracts are not subjected to peer review and are not considered to be a form of scientific publication. The intent is that the information presented will eventually be submitted as a paper to a journal where it will undergo appropriate peer review by experts in that field of research. This never happened in this case, probably because the study performed did not have the scientific rigor required for publication. The student investigated contaminants in bottled water and found a number of organic compounds, including diethylhexyladipate. Apparently unaware that this is not used in polyester bottles, the author assumed it was leaching out of the plastic. Stimulated by this, the Idaho student examined a variety of other plastic bottles and found DEHA in the water they contained leading to the conclusion that “migration of DEHA was not limited to polyester bottles alone and other bottles may also pose a health hazard.”
But a critical control experiment was never performed. Was there any DEHA in water stored in glass bottles or in water that came from the tap water? The answer is yes. Because DEHA is a ubiquitous plasticizer used in the manufacture of items ranging from toys to shower curtains, it shows up in trace amounts everywhere. You can find it in food, clothing and water. We know this because the Swiss Federal Laboratories for Materials Testing and Research studied this issue extensively. All sorts of water samples that had never been in contact with any plastic bottle showed traces of DEHA! Whether the samples came from plastic bottles or glass bottles they contained the inconsequential amount of about 0.01 to 0.05 parts per billion. The World Health Organization has set a maximum of 80 ppb for DEHA in drinking water so there is simply no issue here with plastic bottles. At least not as far as DEHA goes. There may be reasons not to refill water bottles, but that has to do with possible bacterial contamination, not with the leaching of diethylhexyladipate.
So far, so good. But what about the business of DEHA making people feel younger? That’s a puzzler. But it can probably be traced to someone’s fingers dancing on the keyboard while they were “researching” the DEHA-water bottle connection. A little slip and they typed DHEA instead of DEHA. All of a sudden, claims of the potential rejuvenating properties of dehydroepiandrosterone began to frolic on the screen. A “fountain of youth,” many websites claim, a “superhormone!” And what is this miracle? DHEA is a naturally occurring compound synthesized from cholesterol in the adrenal glands. Production peaks in the 20s and then declines so that by the eight decade the amount of circulating DHEA is only 20% of that found during the vigor of youth.
Reasonably, researchers began to explore the possibility that maintaining the DHEA in the blood at levels found in young people may help avert some of the problems of aging. Animal studies showed some intriguing results in terms of delaying cancer and the hardening of arteries. A widely reported study in humans showed that taking 50 mgs of DHEA for three months resulted in an improved feeling of well-being. And then there is the other side of the coin. Researchers worry that DHEA being a relative of testosterone may increase the risk of prostate cancer in men and cause facial hair growth in women. DHEA is illegal in Canada but can be freely sold as a “dietary supplement” in the US. Curiously, people who would not consider taking prescription hormone replacement therapy, uncritically jump on the DHEA bandwagon.
Obviously, DHEA is not the same as DEHA, but neither substance is present in the polyester used to make water bottles. Manufacturers are certainly not sneaking DHEA into the plastic in order to increase sales by making people feel young. But it is interesting to explore how a collection of scientific smidgens can be blended together into meaningless hodge-podge.