Who doesn’t love kale? It’s probably ranks as one of the most-loved vegetables on the planet. Let’s face it: kale is a superstar in the vegetable kingdom. And for good reason: steamed kale has been shown to lower cholesterol levels. Regular consumption has been linked to reducing at least five types of cancer, including: bladder, breast, colon, ovary and prostate. It’s powerful compounds known as glucosinolates have even been found to regulate detoxification at the genetic level. And that’s not to mention its superfood status when it comes to other nutrients like vitamin K, A, calcium and a group of compounds known as flavonoids, of which kale has more than just about any other vegetable.
But, what if (and don’t hate the messenger here), the story about kale wasn’t all good news? In a recent blog known as “The Vegetable Detective” Todd Oppenheimer raised the concern that kale, even organic kale, while healthy in moderate amounts, could (at least in theory) be linked to thallium poisoning. He reported that Ernie Hubbard, a molecular biologist with a background in biochemistry and genetics in Marin County, California, found that a surprising number of his private practice clients reported the same symptoms: chronic fatigue, heart arrhythmias, skin and hair issues, neurological problems, foggy thinking, digestive troubles and gluten-sensitivity, to name a few. So when a company contacted him to test a detoxification product “ZNatural” it was developing to bind (or “chelate”) to toxins like heavy metals to eliminate them in the urine, he agreed.
Twenty clients agreed to try the product and Hubbard went to work testing their urine samples. High levels of the heavy metal thallium kept showing up. According to Oppenheimer, around the same time, Hubbard found a study that found cruciferous vegetables are excellent accumulators of heavy metals, including thallium. Cruciferous vegetables include: kale, broccoli, cauliflower, cabbage, brussels sprouts, collard and mustard greens. While considering kale’s explosion in popularity, Hubbard reportedly made the link between kale and possible thallium toxicity.
According to MedicineNet.com:
“Thallium is a soft, malleable gray metal that was previously widely used in rat poisons and insecticides. Thallium itself and compounds containing the element are highly toxic. It is particularly dangerous because compounds containing thallium are colorless, odorless, and tasteless. Because of this high toxicity, the World Health Organization (WHO) recommends against the use of thallium in rodent and insect poisons.”Thallium is also found in cigarette smoke and is used in some medical imaging tests.
So, it’s possible that thanks to our overuse of thallium-containing insecticides, we may have left excessive amounts of thallium behind in the soil. And, due to kale’s natural detoxification properties, could it be cleaning up the soil and the environment but accumulating in the vegetable itself? According to the research, which it is still in its infancy, it is possible.
Does that mean that we should turn our backs on those kale juices, quinoa and kale dishes, kale curries, or kale salad wraps? Of course not. How could we instantaneously reject the very superfood that has been imparting its anti-inflammatory, heart-health promoting, digestive enhancing and anti-cancer properties to us for so many years? Does it mean that, like most things eaten in excess, it may have some damaging effects? Yes, at least theoretically. Further research will help us to know whether all kale is prone to bioaccumulating thallium, or whether kale grown in certain regions is more vulnerable, and even what amount might be too much?
In the meantime, it still seems safe to eat kale in moderate amounts, while exercising some caution. After all, thallium poisoning is nothing to balk at. Its symptoms include: nausea, vomiting, diarrhea, hair loss (alopecia), loss of reflexes, convulsions, headaches, muscle wasting and memory issues.
Am I going to keep enjoying this leafy green superfood? Kale yeah!!!