Three pilot studies, conducted in 2014 and 2015, tested samples of fresh vegetables and other foods in Marin and Sonoma counties, here in California, for toxic heavy metals. The analyses of these local farm’s produce (both organic and non-organic) found 6 of 25 foods tested high in thallium. The majority of these elevated findings occurred in samples of kale (Brassiness oleracea) from farmer’s markets and food retailers.
In parallel studies of heavy metals in humans, subjects exhibiting high urine thallium were found to be high consumers of some of the foods testing high in thallium, particularly cruciferous vegetables.
A follow up study found a high percentage of the participants exhibited higher-than-normal levels of toxic heavy metals, particularly thallium, aluminum, and cesium. The subjects with higher-than-normal thallium levels also exhibited varying degrees of symptoms consistent with thallium toxicity including cardiac arrhythmias, fatigue, and hair loss.
When research was found in the medical literature linking high levels of thallium to kale and other cruciferous vegetables, a survey of study participants was conducted and a high correlation was found between elevated urine thallium and high consumption of kale, cabbage, broccoli and other cruciferous vegetables.
Given a half life of 60 days for thallium in the body, simply having a kale smoothie every morning and in salads would give the average kale user sub-clinical symptoms within 6 to 8 months.
The source of the toxins is still unknown but they are looking in to the manure that these foods were grown in first. The certification of vegetable as organic does not include the manure used to grow the foods.
The bottom line is that anyone who is developing symptoms and eating a lot of cruciferous vegetable should change their diet and get tested for heavy metal exposure.
“Thallium Exposure: Environmental Issues” By Michael Rosenbaum, MD and Ernest Hubbard, Townsend Letter, February/March, 2016.