Kale the silent killer?

Sorry, Foodies: We're About to Ruin Kale | Mother Jones:

Today's kale-fixated juice-heads may doing themselves a disservice.

That's a possibility raised by an article in Craftsmanship magazine by Todd Oppenheimer. The piece doesn't establish a definitive link between heavy kale consumption and any health problem, but it does raise the question of whether too much of even a highly nutritious food like kale can have unhappy side effects.

The article focuses on an alt-medicine researcher and molecular biologist named Ernie Hubbard, who began to notice an odd trend among some of his clinic's clients in California's Marin County, a place known for its organic farms, health-food stores, and yoga studios. Extremely health-conscious people were coming into to complain of "persistent but elusive problems": "Chronic fatigue. Skin and hair issues. Arrhythmias and other neurological disorders. Foggy thinking. Gluten sensitivity and other digestive troubles. Sometimes even the possibility of Lyme Disease."

Hubbard began to find detectable levels of a toxic heavy metal called thallium in patients' blood samples—at higher-than-normal leves—as well as in kale leaves from the region. Meanwhile, "over and over," he found that patients complaining ofsymptoms associated with low-level thallium poisoning—fatigue, brain fog, etc.—would also be heavy eaters of kale and related vegetables, like cabbage.

And he found, in the form of this 2006 peer-reviewed paper by Czech researchers, evidence that kale is really good at taking up thallium from soil. The paper concluded that kale's ability to accumulate soil-borne thallium is "very high and can be a serious danger for food chains." And here's a peer-reviewed 2013 paperfrom Chinese researchers finding similar results with green cabbage; a 2015Chinese study finding green cabbage is so good at extracting thallium from soil that it can be used for "phytoremediation"—i.e., purifying soil of a toxin—and a2001 one from a New Zealand team finding formidible thallium-scrounging powers in three other members of the brassica family: watercress, radishes, and turnips.'via Blog this'