My readers and listeners pose all sorts of interesting questions. Like whether or not it is true that water bottlers are putting a risky hormone called diethylhydroxylamine (DEHA) into the plastic used to make the bottles so that people will feel younger and buy more of their product. When I heard this question, I knew that it was nonsense, but it took a fair bit of detective work to uncover how this remarkable query arose. Let me share it with you.
I’m quite sure the starting point is a scare circulating on the Internet about the migration of a chemical commonly referred to as DEHA into water from plastic water bottles. 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 warned that such water bottles should not be refilled but instead be discarded after a single use.
Right off the bat, there are several issues here. First of all, DEHA, it is not an “element.” It is a compound. And it certainly is not a hormone. And in any case, the writer 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. But neither of the “DEHAS” is classified as a carcinogen. Then there is 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 the alarm? As with many other such Internet scares, there is a kernel of truth that has been blown completely out of proportion. In this case, that kernel is found in an abstract of a talk given by a master’s student from the University of Idaho at a scientific conference. Such abstracts are not subject to any 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 review by experts in that field of research. As far as I can tell, that 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? Actually, there is. 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 plastic bottles are simply not an issue here. At least they’re 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? I puzzled over that one for a while. I think that someone’s fingers dancing on the keyboard while they were “researching” the DEHA–water bottle connection made a little slip and typed DHEA instead of DEHA. All of a sudden, claims of the potential rejuvenating properties of dehydroepiandrosterone (DHEA) 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 twenties, and then declines so that by the eighth decade of a person’s life, the amount of circulating DHEA is only 20 percent of that found during the vigor of youth. (Now don’t go jumping to the conclusion that popping cholesterol will increase DHEA in the blood and thereby make you live longer.)
Reasonably, though, 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 milligrams of DHEA for three months resulted in an improved feeling of well-being. But there is another side to this coin. Researchers worry that DHEA, 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 seem to uncritically jump on the DHEA bandwagon.
Now, to get back to answering our original question: DHEA is not the same as DEHA, and neither substance is present in the polyester used to make water bottles. And I really don’t think that manufacturers are sneaking rejuvenating hormones into the plastic in order to increase sales. Such silly, unreliable “they say” stories do, however, cause me to grow a few gray hairs. Hmmm . . . maybe I should try drinking more bottled water.