When April’s here and meadows wide
Once more with spring’s sweet growths are pied
I close each book, drop each pursuit,
And past the brook, no longer mute,
I joyous roam the countryside. (Jessie Redmon Fauset)
[Are there deformed frogs in the brook?]
Today’s roamed countryside was the Kiplinger Natural Area on Kanner Highway in Stuart, a bundle of habitat diversity tucked into a small package—weedy meadow, brook with baby gator, mangrove swamp, river bank, low pine woods, and marsh. The usually modest Gallberry was having its 15 minutes of fame with millions of white flowers abuzz with happy bees. White Pinebarren Aster (Oclemena reticulata) and Elliott’s Milkpea (Galactia elliottii) splashed more white into nature’s garden. Rabbit Bells (Crotalaria rotundifolia) were at their yellow best, and Smilax reached out with tender new tendrils and its yellow-green “lily” blossoms.
We’ll zoom in (again) on Smilax as an example of plants able to make compounds, phytoestrogens, that mimic or interfere with mammalian estrogen hormones and related functions. A lot of natural and unnatural chemicals do that. The “Silent Spring of the 90s,” increasing public awareness of environmental estrogens, was “Our Stolen Future,” 1997 by Theo Colborn and collaborators.
There are things to worry about in the estrogen endocrine-disrupting realm.
Thing 1: Natural botanical “phytoestrogens” can impact animals, including humans for better or worse, an observation not lost on diet- and herbal-conscious writers. When we talk of artificial estrogens, we’re not merely talking about potentially feminized males (although possible, as in the famous “teenie weenies” on Lake Apopka gators), but also fundamental developmental disruption and cancers, especially breast cancers. Hormonal activity and the altered gene control of cancers are no doubt intertwined. As two examples of dietary plant-derived phytoestrogenic booboos, A) multiple post-menopausal women have suffered uterine ailments apparently from high consumption of soy products (legumes can be high in phytoestrogens). And B) a man developed breast cancer after six years of herbal remedies rich in phytoestrogens.
Some observers suspect that traditional plant medicines for reproductive complaints often tend to involve phytoestrogens or similar endocrine-active compounds. After all, the first birth control pills came indirectly from yams. And that brings us back to Smilax.
Smilax is a popular trail nibble and as a genus serves worldwide in traditional medicines including several hormonally related problems, including menstrual complaints, perimenopausal symptoms (for which it is promoted), impotence, prostate enlargement, childbirth, and psoriasis, which has a hormonal connection. Smilax is a much-touted source of hormonally active compounds..
(Disclaimers: I am using the term “phytoestrogen” broadly to include compounds that mimic estrogens, or that impact directly or indirectly regulation of the mammalian estrogen-related system. Also, Smilax has traditional non-reproductive uses too, and of course human history is loaded with attempts to alleviate reproductive ailments.)
Moving on to additional worrisome things:
Thing 2. My colleague Maura Merkal last week shared a report on pesticides in South Florida waters: “Ambient Pesticide Monitoring Network: 1992-2007” (linked below). Here is a fun fact from the report: The chlorinated agricultural and lawn-grass herbicide Atrazine turned up at every sampling location. Did I mention, every sampling location in our general area. 1517 detections.
Crummy, but how does it tie to Smilax? We’re getting there. A recent issue of the New Yorker Magazine (Feb. 10 2014) recounted an epic battle between University of California researcher Dr. Tyrone Hayes and the manufacturer of Atrazine. The rub grew out of Dr. Haye’s research conclusions that a profitable herbicide is an estrogen-related source of developmental deformities in amphibians, or let’s call them canaries in the water.
To comfort ourselves we may say, sure there’s Atrazine in all the water, but optimists and vested interests claim the effects are not proven, and the concentrations are low. (It was not “proven” that cigarettes cause lung cancer.) There’s been a loud “Hayes is nuts” reaction to his research, including assertions that the results can’t be replicated and that his alarm is debunked. But there are also independent indications that Hayes is not nuts, and there is evidence of human damage from Atrazine in the water. It would be an understatement to call this dispute controversial. Interested persons can conduct their own Google research on this remarkable dustup. (Readers interested in a broad history of inconvenient research in relation to economic interests might enjoy David Michaels’s “Doubt is Their Product.”)
Thing 3. Now let’s worry that no matter how hormonally pernicious Atrazine may or may not be, there are a lot of additional estrogen-interfering chemicals in the air and water. Addiitonal estrogen-related compounds haunt the Ambient Pesticide study. And even if Atrazine is in “low” concentrations now, we’re adding more and more, and what about combined effects of mixed estrogen mimics? That brings us to worrisome thing #4.
Thing 4: According to Our Stolen Future and other sources, hormonally-related chemicals can work in astoundingly low concentrations exponentially below what we tend to talk about in terms of toxicity thresholds, such as killing water-fleas. (“Didn’t kill the fleas, so I guess we’re safe” does not comfort me.) Hormones and their mimics seem to have chronic effects at levels of parts per billion, or, yikes, even parts per trillion. But admittedly all very general and murky.
To return to native plants, why would a natural organic plant be so crass as to make hormonally -interfering compounds? Plants able to sabotage their herbivores’ baby-making don’t get gobbled. Human case in point: Cottonseed oil, containing phytoestrogens, is touted as a potential male oral contraceptive. Turns out couples in regions heavy on dietary cottonseed oil have trouble making babies.
Are Dr. Hayes and his supporters correct? As the detractors say, there is no “proof,” but the fear of Dollarweed in my lawn ranks below my fear of impaired aquatic ecosystems, deformed babies, and adolescent cancers.