By Mike Pomranz
Updated July 16, 2015
Credit: © Jeff Wasserman / Alamy

Kale might still be the darling vegetable of the health conscious set, but this week it’s come under fire thanks to a recently published article. In it a biologist claims that kale (and related vegetables), eaten in high quantities, might actually be poisoning people.

The potential bombshell comes from the relatively new Craftsmanship Magazine, claiming kale and other members of the crucifer family including cabbage, broccoli and cauliflower may be giving people thallium poisoning. Thallium is a heavy metal that used to be used in rat poison, although it is banned now. In humans, excess thallium can cause symptoms like fatigue and hair loss. The revelation comes from Ernie Hubbard, a “molecular biologist with a background in biochemistry and genetics” who works with an alternative health clinic in Marin County, California.

Hubbard says he’s found a connection between patients at his clinic who eat large amounts of crucifers and high levels of thallium. He cites a 2006 study from the Czech Republic that says that crucifers are “hyperaccumulators” of thallium, meaning that they are able to easily soak up the metal from the soil they grow in. When patients reduced the amount of these vegetables in their diet, Hubbard says that thallium levels dropped and the patients’ symptoms went away. The Czech study is not the first to find problems with crucifers. In 2001, research in New Zealand came to similar conclusions.

It’s a big claim against some very popular vegetables. Of course, even if it’s true, it’s not the veggies fault: They are just taking in what they are finding in the ground.

It’s worth noting that these concerns are based on people who ate a lot of these: One woman said she ate cabbage every single day. But it’s a story worth keeping an eye on. Especially if you’re looking for a reason not to eat your broccoli.