These allegations have attracted major media attention, but there’s an awkward fact rarely mentioned in the headlines: a large body of research has failed to produce any solid evidence that paraquat exposure causes Parkinson’s.
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Join hosts Dr. Liza Dunn and GLP contributor Cameron English on episode 248 of Science Facts and Fallacies as they break down this recent GLP feature:
Only available to licensed pesticide applicators, paraquat was used in agriculture without incident for many years. Long after it was commercialized, however, scientists discovered the herbicide was chemically very similar to an impurity found in illicit opioids that caused Parkinson-like symptoms in several recreational drug users. This discovery fueled rampant speculation about the risks of paraquat exposure, though subsequent research showed that the herbicide doesn’t cross the blood-brain barrier efficiently enough to cause the neurological damage at the root of PD.
Studies have also shown that workers at paraquat manufacturing plants, individuals with the highest exposure to the chemical, are no more likely to develop Parkinson’s than the general population. With this data in mind, is there any additional evidence that can help settle the dispute about paraquat and Parkinson’s? Let’s take a closer look at the science and politics surrounding this controversial herbicide.
Dr. Liza Dunn is a medical toxicologist and the medical affairs lead at Bayer Crop Science. Follow her on X @DrLizaMD
Cameron J. English is the director of bio-sciences at the American Council on Science and Health. Visit his website and follow him on X @camjenglish
