Kale is revered as one of the healthiest and trendiest vegetables (although some argue that people need to cool it with the kale mania). But anyone with kale in his or her diet should pay attention to this study, which suggests that kale may not be as good for you as you think.
Ernie Hubbard is a molecular biologist at the Preventive Medical Center of Marin and California who had a few patients test out a detoxifying formula called Znatural. When collecting urine samples from 20 participants, he noticed that a few people’s samples contained traces of thallium and cesium — two toxic heavy metal elements.
Hubbard asked the patients to list their favorite vegetables and found that a few of them cited kale. He found that people who came in with chronic problems such as fatigue, neurological disorders, and digestive issues — all of which could be attributed to thallium — said that they often ate this increasingly popular vegetable.
The thallium levels in kale may be linked to coal production. Hubbard states that thallium is traced back to coal-burning, and coal ash is often sold as fertilizer for crops. The crops absorb the thallium, animals eat the plants, and the cycle continues. Kale just so happens to be the point of focus because it is a popular vegetable, but more research will be done into others.
Thallium is the first ingredient in rat poison and can also be found in other dark green vegetables, such as cabbage, broccoli, cauliflower, mustard greens, and collard greens. A Czech study from 2006 described these cruciferous vegetables as “hyperaccumulators” of thallium.