Glyphosate-based herbicides, such as Roundup®, are widely used in the United States in crops, gardens, and lawncare. Luoping Zhang, PhD, MS, Adjunct Professor at University of California, Berkeley, and colleagues revealed in a study that exposure to glyphosate increases an individual's chance of developing non-Hodgkin lymphoma (NHL). In this interview with i3 Health, Dr. Zhang shared insights about the implications of exposure to glyphosate-based herbicides and recommendations for avoiding exposure.
Can you share your perspective on the significance of the study's findings concerning the link between NHL and glyphosate-based herbicides?
Luoping Zhang, PhD, MS: We have found that the overall relative risk of NHL among individuals exposed to higher levels and/or longer periods of glyphosate-based herbicides (GBHs) is increased from 30% to 41% in average exposure groups (never vs ever). The different exposure groups (high vs low, or never vs ever) were reported from original studies if they were available and not from our assessment. From our meta-analysis results, it is clear that the NHL relative risk is increased among individuals exposed to GBHs, no matter if they were in average exposure groups (30%) or in higher exposed groups (41%). While the findings are from human studies, they are further supported with data from animal and mechanistic studies.
How do glyphosate-based herbicides cause cancer in humans?
Dr. Zhang: A quick answer to your good question is that we don't know exactly how yet. However, both genotoxic and non-genotoxic mechanisms may have the potential for GBHs to induce cancer in humans.
Is there a safe concentration of glyphosate to use, or should it be completely avoided?
Dr. Zhang: Our study reports the results from our current meta-analysis and provides additional supporting evidence from available animal and mechanistic data that GBHs are linked to NHL. However, the study was not designed for exposure and risk assessments. Thus, I cannot really tell you if there is any safe level of using GBHs, but from our study findings, one (or I, as a public health researcher) could at least recommend that the use of glyphosate and/or GBHs should be under strict regulations, and users should be protected.
What are your thoughts concerning glyphosates used as pesticides on food?
Dr. Zhang: Watch out for what you eat, and get to know how many types of food have been contaminated with glyphosate and GBHs. Also, keep in mind that the cumulative exposure counts.
What are the next steps that need to be taken to help people avoid the risk of GBHs?
Dr. Zhang: Knowledge is power! The first step should be to let the general population know about the worldwide use and cancer risk of GBHs.
About Dr. Zhang
Luoping Zhang, PhD, MS, is an Adjunct Professor of Toxicology at the University of California, Berkeley. Dr. Zhang's research interests include the association of chemical exposures and increased risk of cancers, mechanisms of chemically induced toxicities, and application of omic-based genomic and epigenomic technologies to discover new biomarkers.
For More Information
Zhang L, Rana I, Shaffer RM, et al (2019). Exposure to glyphosate-based herbicides and risk for non-Hodgkin lymphoma: a meta-analysis and supporting evidence. Mutat Res. [Epub ahead of print] DOI:10.1016/j.mrrev.2019.02.001
Transcript edited for clarity. Any views expressed above are the speaker's own and do not necessarily represent the views of i3 Health.