Cotton tampons, dioxins, and endometriosis
If we had a magic bullet to cut the chances of endometriosis by one-third wouldn’t it be great? We do--decrease your dioxin intake. Men, hit the back buttons on your browsers quick ... this is about women’s hygiene products.
An email about potential hazards of toxic substances in tampons seems to be making the rounds again. The email recommends all-cotton tampons. Cotton is one of the most pesticide intensive agricultural products. This month’s National Wildlife magazine has an expose’ by Doreen Cubie on the aerial application of herbicides to cotton fields prior to harvest. Whether or not conventional tampons are a health hazard to women, my own conclusion is that conventionally farmed cotton is bad for our Mother Earth. Many herbicides are endocrine disruptors in mammals, reptiles, and birds. Aerial application of insecticides is a hazard to birds and other “nontarget” animals (that is, living things that aren’t insect pests, including us). I’ve been buying socks made of unbleached organically grown cotton for a few years. You probably won’t find them at the shopping mall or Walmart, but here in Madison the Willy Street Grocery Coop carries them.
But what about the health hazards of dioxin in tampons? A look around the web shows that allegations of dioxins and asbestos in tampons surfaced as early as 1998. The FDA claims that dioxins are “below the limits of detection” (about 1 part per trillion, or ppt). The FDA’s assumptions look shaky to me--is a 1 ppt limit of detection fine enough, and should the FDA should be comparing the dioxin in tampons to the concentrations of dioxin in the typical American, as if you can’t absorb more of it just because you already have quite a bit of it inside you. But let’s look deeper.
Research with rhesus monkeys conducted at UW-Madison found that female monkeys who ate food tainted with dioxin at either 5 or 25 ppt (yes, the “t” is for trillion) for 4 years early in life had about double the rate of endometriosis 10 years later compared to the control group. Let me emphasize the main point -- 10 years after the monkeys stopped eating contaminated feed a difference in endometriosis was seen. Higher dioxin earlier in life led to higher endometriosis later in life. (See Rier et al., 1993 in Fundamental and Applied Toxicology; or Rier et al., 1995, Environmental Health Perspectives Supplements--available free online). A recent epidemiological study in women confirms the monkey work of over a decade ago (see Helier et al., 2005, in Fertility & Sterility). An increase of 10 picograms of dioxin per gram of blood lipids almost tripled the chance of endometriosis in women.
Now let’s think about the difference between exposure to dioxin in tampons and consuming dioxin-contaminated food. Little is known about skin absorption of dioxin, but painting dioxin-laden compounds on the skin of mice induces skin cancer. What about applying dioxin-contaminated tampons directly to mucous membranes close to the reproductive organs? No one knows how much of the dioxins will be absorbed under these circumstances or whether it will directly target the nearby reproductive organs.
Dioxins can also be absorbed out of the air, but the most likely source for most of us is food. Dioxins are lipophilic and so they bio-magnify up the food chain. People who eat a lot of meat are eating more dioxins (and related contaminants such as furans and PCBs) than those who eat less meat. The dioxins are carried in the fat in meat. So eat less meat, or eat organically raised meat. Organically raised meat should have lower contamination with dioxins because organic standards prohibit feeding animal products to the animals. In 2003 a panel of the Institute of Medicine of the National Academy of Sciences concluded that one way to reduce dioxins in meat was to stop feeding animal products to the animals.
Ladies, if you have endometriosis, maybe you should blame contaminated meat rather than your tampons. But we need research on the extent to which dioxins can be absorbed from tampons, and also probably better monitoring or tampons using assays with a lower limit of detection. In the meantime, we don’t need a cancer body count in order for a pollutant like dioxin to be regulated. Women know that endometriosis creates sheer misery.
Bird Sightings: An osprey was perched in a tree on East Dayton St. today. A couple of weeks ago a bald eagle was soaring near the Yahara River between East Washington and East Johnson. I thought it was looking for fish, but maybe it was after roadkill on these major arteries in Madison.
Friday, February 24, 2006
