Sour Weeds and Kidney Stones
Wild weedy greens
Several species of Rumex are roadside and ditch weeds that originated in Europe, but have now been transported around the globe, joining weedy communities whose main differences seem to relate only to latitude rather than continent. The docks, including curly dock, are rosette-forming plants, that is, they first produce a ground-level cluster of leaves by inhibiting the lengthening of the stem internodes, then quickly shoot up a flowering stalk as the season warms. When dock leaves are young and tender, they make a nice addition to a salad, or you can munch on them as you walk down a country lane. The taste is a pleasant sourness on account of the high content of oxalic acid.
But, should you make a habit of curly dock salads or cooked greens, you run the risk of developing kidney stones, because being a dicarboxylic acid, oxalic acid grips calcium in a claw-like molecular structure, and the insoluble calcium oxalate crystallizes somewhere in your urinary tract. If the crystal tumbles down your ureter, it may block the flow of urine from the kidney to the bladder, causing you to gasp with pain. I had my first episode in the middle of the Namib Desert of southern Africa, many miles from the nearest human habitation. I think I can safely say that it had little to do with curly dock, but it did mean a painful, seemingly endless, roadless return to the Namibian coast to a 6-bed hospital in Lüderitz Bay where I was the only patient for three days. As I was under the care of three nurses with lots of time on their hands, I was sorry when my companions came back to pick me up. This cute little hospital has since been superceded by a modern medical center. I’m sure they have more than six beds and three nurses.
So back to weeds. In common usage, we tend to think of weeds as undesirable plants, so it is easy to lose sight of the fact that most of our crops originated as weeds--- all the cereals, kohls and mustards are just fancy weeds, as are corn, beans, quinoa and squash. Through selection, these weeds induced us humans to cater to their needs while serving our own needs and desires. Wheat was first domesticated over 9000 years ago. It’s not clear who was selecting who during domestication, but pleasing people was certainly very good for the reproductive success of these humble weeds. Buckwheat, a rosette-forming relative of curly dock has been associated with humans for over 6000 years, producing a crop even under cold or short-season conditions. When selected to the extreme, rosette-forming gave us the lettuce and cabbage.
Oddly, among ecologists, studying weedy communities seems to be déclassé. The high status goes to studying undisturbed ecosystems that are painfully difficult to get to, and painfully in danger of destruction. Most weeds depend upon habitats disturbed by humans, such as pastures, roadsides, yards and city streets. It is perhaps because weeds appear to have such low personal standards that ecologists look down upon them. But stop to think for a moment--- what does it take to survive and reproduce in a crack in a New York City sidewalk, or in the 10 inches of polluted soil between the sidewalk and the street, dosed every day with burger wrappers, cigarette butts and dog urine? Few plants can meet this challenge, so when I look at these weeds, I am overcome with admiration.
Humans mess up just about every ecosystem they enter, and then get mad when weeds take up the messed-up space. Perhaps it would help to remember that many of the plant crops we now relish started out as camp followers of our destruction. No doubt, as our destruction continues unabated, there are more weeds waiting to join the ranks, and perhaps one day, curly dock will be the special greens o' the day in a high-tone New York City restaurant.
I love these essays.
Good essay, as usual. You had my attention at "kidney stones", one of my medical boogeymen. The uro docs were on target with recommending potassium citrate to break the chemical hold you described. For the millions similarly affected, the real salvation is water, lots of water.