Kale is widely known as a highly nutritious vegetable. Katie Donohue, a daily kale consumer with a degree from North Carolina State University in Agricultural Education, appreciates kale in her morning smoothies. Donohue says "kale is super hardy, and easy to incorporate into any meal." This is true - plus kale contains "high levels of vitamins, minerals, and brain-boosting phytonutrients" (LiveScience). Phytonutrients, also known as phytochemicals, are described by nutrition scientists at the University of California Davis as a "large group of plant-derived compounds hypothesized to be responsible for much of the disease protection conferred from diets high in [plant-based foods and beverages]." Don't stop reading though. Put down the green smoothie for a minute and read on.
Mother Jones, a magazine devoted to politics, the environment, human rights and culture, shared today that kale has a knack for absorbing thallium when the metal is present in the soil where kale plants are flourishing. Later, when this kale is eaten, the thallium from the vegetable leaves is absorbed into the bloodstream of the person ingesting the kale.
Why is this bad? Thallium is a tasteless and odorless metal that at one point in time was an ingredient in rat poison. Cases of thallium poisoning see symptoms of fatigue, nausea, pain, increased heart rate, and hypertension in patients. In more severe cases, patients are known to experience nerve and muscle damage (CDC).
Fortunately, it is only in certain regions where kale grows in the presence of thallium-contaminated soil. Thallium exists in much larger quantities under the earth's surface, and is only able to escape its "natural habitat" so-to-speak during cases of fracking, oil drilling, and/or well-drilling that draws the harmful metals into irrigation water and then into the soil (Craftsmanship). Another reason not to worry is that large amounts of thallium-containing kale would have to be ingested for a person to attain even low-level thallium poisoning.
Should nutritionists declare war on kale? No. Like most things in life, kale will most likely continue to be harmless when consumed in moderation. It's always smart to know where your food comes from, though. Hopefully in the future farmers can avoid growing kale in areas affected by thallium pollution.
In the video below, the nutrition benefits and types of kale are described in further detail. Watch until the end and receive many kale preparation tips and of course, recipes.
Sources: CDC, Mother Jones