A research letter published in JAMA reveals a startling increase in people’s exposure to the weed killer glyphosate (JAMA, Oct. 24/31, 2017). This herbicide, sold under the brand name Roundup, is widely used on corn, soy, wheat and oats.
Genetically modified (GMO) crops have allowed much higher concentrations of glyphosate to be applied. Current use of the herbicide is 15 times higher than two decades ago.
Are People Exposed to the Herbicide?
Researchers compared urine levels of glyphosate in an older population living in the San Diego area. Before GMO crops were commonly used, almost none of the study subjects had glyphosate in their urine. By 2016 roughly 70 percent of these individuals had measurable amounts of the herbicide in urine specimens.
Is It Safe to Eat Glyphosate-Containing Foods?
The safety of consuming glyphosate remains controversial. While the International Agency for Research on Cancer (IARC) concluded in 2015 that glyphosate exposure might cause cancer, a different review by the European Union found that glyphosate exposure in Europe is too low to represent a public health concern (Tarazona et al, Archives of Toxicology, Aug. 2017). The state of California has declared this chemical a probable carcinogen.
Worries About Another Herbicide:
Glyphosate is not the only herbicide used to reduce weeds on crops. Recently, NPR listeners heard about dicamba and the controversy surrounding its suddenly increased use in the Midwest. The New York Times ran an extensive story about the difficulties farmers are experiencing as their neighbors start using more dicamba. These reports focused on the environmental and economic consequences of applying this compound liberally to GMO soy and certain other crops.
The trouble is that dicamba drifts during and after application, so plants that weren’t supposed to be exposed to it end up affected. As one farmer noted, growing non-GMO crops will soon be impossible in many parts of the country. The most recent story notes that the dicamba problem is severe.
Is Dicamba Safe for Human Consumption?
Clearly, in such an environment, we are already consuming foods that contain dicamba. So far as we know, studies on dicamba toxicity have focused primarily on laboratory animals such as rats (Brkic et al, Environmental Toxicology and Pharmacology, May 2015) and beneficial insects such as ladybugs (Freydier & Lundgren, Ecotoxicology, Aug. 2016).
At this point, we have not seen studies showing how dicamba exposure affects human health. We don’t expect this will be any easier to determine than the effects of Roundup, and it is likely to be equally controversial. We do hope such studies will be done, however. In fact, since these herbicides are increasingly being used together, we urge scientists to examine the health effects of glyphosate and dicamba combined.
In the meantime, how can we minimize our exposure to these herbicides? We may not be able to do so completely, although relying on organic foods and those produced on small local farms not using the chemicals should help. We welcome your thoughts on this thorny topic.
