Kale might not be as healthy as you think it is

Could kale actually be dangerous?

Could kale actually be dangerous?  (AP Photo/The Pantagraph, Steve Smedley)

McDonald's might want to rethink its latest venture with kale. An article in Craftmanship magazine says everyone's favorite health food might produce some rather unwelcome side effects, including chronic fatigue, digestive issues, arrhythmias, and more.

According to Mother Jones, the article "doesn't establish a definitive link between heavy kale consumption and any health problem," but it does raise suspicion. It describes how, after hearing health-food fans complain of symptoms similar to those of low-level thallium poisoning, molecular biologist Ernie Hubbard identified the toxic heavy metal in patients’ urine and in kale.

He then reviewed studies published over a 15-year period and found kale, cabbage, watercress, radishes, and turnips, are particularly good at pulling thallium from soil. One patient who called herself the "cabbage queen" had thallium levels seven times higher than the threshold safety limit and claimed her hair was falling out "in clumps." No, that doesn’t mean the veggies at your local supermarket are going to make you go bald.

Thallium is typically only found at concerning levels in "nearby cement plants, oil drilling, smelting, and, most of all, in the ash that results from coal burning," Craftmanship reports.

Though Hubbard couldn't pin down the source of the thallium in his kale, he suspects it might be related to coal ash spread as fertilizer, or perhaps wastewater from fracking operations—but it's all speculative for now.

Don't trust kale? Scientists have developed a new strain of seaweed, known as dulse, that contains twice the nutritional value of kale and, amazingly, tastes like bacon, reports the AP.

(Or you could go with regular old kelp.)

This article originally appeared on Newser: Your Favorite Health Food Has a Dark Side

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