The Kale Controversy!5 years ago | Nutrition
By Monya De, MD, MPH and the pH Healthcare professionals
No less a magazine than Mother Jones recently published an account of an alternative medicine researcher claiming the truly horrifying: kale might be bad for you. His patients, otherwise healthy, started presenting with digestive problems, fatigue, and skin and hair problems. He found that a lot of them had elevated thallium levels — and that a lot of them ate significant amounts of brassicas, the plant family that includes kale and cabbage. When he had some patients remove these foods from their diet, their thallium levels dropped and their symptoms improved.
Personally, I enjoy the noble feeling I get from dropping a few leafy bits of kale into my otherwise sweet smoothie in the morning, just like countless other people trying to find some nutrition in the minefield that is American food. The thallium issue, therefore, is a major one.
So, what is thallium?
Thallium is an odorless gray metal. Symptoms of exposure to a lot of thallium include abdominal pain, vomiting, pain in the legs and arms, fatigue and hair loss. In smaller doses, the gastrointestinal and neurological side effects can be delayed several days. This metal has even been used as a murder weapon, because it isn’t easy to detect. Previously, it was used as rat poison, but is now banned in the United States, other than as an import to be used in the making of watches and jewelry. Activated charcoal or Prussian blue are the antidotes of choice.
What does thallium have to do with kale?
Some researchers have found that kale and other brassicas (plants in the mustard family, also referred to as cruciferous vegetables, such as bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, mustard greens and even canola oil) like to soak up thallium from soil. This, of course, assumes that there is thallium in the soil — the higher the concentration, the more likely it is that your kale leaf will have some in it. In the case of the alternative medicine researcher, his patients tested positive for abnormal thallium levels, but it’s unclear why the soil contained it. Even as early as 1986, scientists presented the idea that our main exposure to thallium was from brassica vegetables picked from contaminated soil.
The caveat, though, is that brassicas in large amounts — think your friend that will only eat kale salads at restaurants and juices daily — can also reduce thyroid levels, leading to symptoms like fatigue and hair loss. Hence, without knowing the thyroid levels of the aforementioned patients, it’s hard to know exactly what was affecting them. Maybe it was actually their thyroid levels, and the thallium level, while high, wasn’t enough to cause damage. Another caveat is that researchers haven’t proven that symptoms get worse with higher levels of thallium in the body, just that thallium is generally bad for us.
What can you do to avoid adverse effects of thallium?
First: Do everything in moderation. Avoid living on cabbage soup or kale alone. Eat a varied diet. If you eat a kale salad because everything else is unhealthy at the restaurant, eat bell peppers and tomatoes the next day. These vegetables come from a different family and are unlikely to concentrate thallium or interfere with the thyroid.
Second: Pay attention to the source of your produce. It’s impossible to know what kind of land feeds imported vegetables, but when it comes to farmer’s market vegetables, you can do a little Internet research to find out how the farms’ inspections have gone. You can also see which farms are close to areas with fracking contamination.
Lastly: If you want to take a supplement to counteract potential thallium exposure, selenium supports the thyroid and blocks the effects of thallium, and vitamin E is a well-known “good for the liver” supplement that protects against metal toxicity.
Enjoy Your Healthy Life!
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