Glyphosate is an herbicide that kills broadleaf plants and grasses. It is one of the most widely used herbicides in the United States and is found in Roundup, a product originally created by Monsanto Company and now sold via Bayer, which acquired Monsanto in 2018. The company also produces Roundup-ready seed genetically modified to resist glyphosate, allowing farmers to kill weeds without affecting their crops. Some farmers spray crops with Roundup to kill plants and speed the drying of grain. This gives them more control over when they can harvest crops.
The weed killer is the subject of hot debate in the scientific community, especially regarding whether it causes cancer. But one study has raised concern about a possible connection between glyphosate and celiac disease.
The 2013 study suggested there was a connection between the growing use of glyphosate and an increase in celiac disease, but its conclusions were controversial and have been called into question by other scientists.
Mainly, the study was faulted for not providing any real evidence that the herbicide was connected to celiac disease and for putting forward theories as fact. No additional research on the connection has been published by other scientists.
For patients, that means there is much more we don’t know than we do know about glyphosate and celiac disease and gluten sensitivity. Robust and scientifically valid follow-up is needed before any conclusions can be drawn.
What researchers say about celiac disease
Published in the journal Interdisciplinary Toxicology, the study begins by proposing that “glyphosate, the active ingredient in the herbicide, Roundup, is the most important causal factor” in an increase in celiac disease and gluten intolerance worldwide. It concludes that characteristics of celiac disease can be explained by glyphosate properties. The characteristics include deficiencies in some nutrients, an overgrowth of pathogens in the intestine coupled with a decrease in beneficial biota, impaired serotonin signaling and an increased synthesis of metabolites.
“Fish exposed to glyphosate develop digestive problems that are reminiscent of celiac disease. Celiac disease is associated with imbalances in gut bacteria that can be fully explained by the known effects of glyphosate on gut bacteria,” the authors wrote.
Additionally, the study says, celiac disease patients have an increased risk of non-Hodgkin’s lymphoma, which has also been implicated in glyphosate exposure. Reproductive issues associated with celiac disease, such as infertility, miscarriages, and birth defects, can also be explained by glyphosate, according to the authors. They hypothesize that the herbicide affects the tight junctions between cells in the intestine, leading to the leaky gut that is associated with celiac disease. They also point to parallel relationships between glyphosate and these conditions in animals.
Study methods challenged
In 2017, a follow-up study was published in the journal Frontiers in Public Health by researchers from the department of medical and molecular genetics, King’s College London. They laid out the debate about “facts and facilities in the debate about glyphosate toxicity.”
The authors describe how controversial glyphosate and other pesticides are in the research world. “Reviews have been published by individuals who are consultants and employees of companies commercializing glyphosate-based herbicides in support of glyphosate’s reapproval by regulatory agencies” the King’s College researchers wrote, noting that the conclusion of the reviews is that glyphosate is safe at levels below regulatory permissible limits. “In contrast, reviews conducted by academic scientists independent of industry report toxic effects below regulatory limits, as well as shortcomings of the current regulatory evaluation of risks associated with glyphosate exposures.”
However, the research related to celiac disease and glyphosate exposure was criticized for being based on deductive reasoning, unsubstantiated theories, and speculation.
The authors of the follow-up study described the deductive reasoning used this way: Since glyphosate could have effects on the gut microbiome and since non-celiac gluten sensitivity is associated with imbalances in gut bacterial populations, glyphosate could fully explain the etiology of this condition.
“We found that their conclusions are not supported by the available scientific evidence,” the authors the wrote, adding that the study about gluten-related disorders “misled the public, the scientific community and regulators.”
The 2017 review also noted that future research investigating the toxicity of these pesticides containing glyphosate, especially at levels of ingestion that are typical for human populations, is much needed. In particular, the authors wrote, “a causative link between glyphosate and gut microbiome-associated intestinal disorders remains hypothetical but nonetheless an important area to be investigated.
Concerns about glyphosate and cancer
The relationship between glyphosate and cancer has been widely investigated, with numerous studies coming to conflicting conclusions.
However, The World Health Organization International Agency for Research on Cancer categorizes glyphosate as “potentially carcinogenic.” Twenty seven countries, from Argentina to Vietnam, ban or restrict its use. However, the United States is not among them, with the Environmental Protection Agency (EPA) taking the position that glyphosate “has a low toxicity for people.”
In December 2017, the EPA issued a Draft Risk Assessments for Glyphosate concluding that glyphosate is not likely to be carcinogenic in humans. The agency notes that while the cancer agency for WHO has concluded glyphosate may be a carcinogen, and the Joint Food and Agriculture Organization (WHO) and the European Food Safety Authority have determined that it is unlikely to be a carcinogen.
Meanwhile, California warns consumers about glyphosate, including it on the state’s 65 list of chemicals and substances known to cause cancer. A number of other U.S. cities ban or restrict its use.
In March, a jury awarded a man $80 million in damages in a lawsuit alleging exposure to Roundup caused his non-Hodgkin’s lymphoma. Last year in the first case to go to trial, a San Francisco jury ruled that Roundup gave a former school groundskeeper terminal cancer. Numerous other lawsuits have also been filed.
Reducing glyphosate exposure
If you would like to reduce your exposure to glyphosates, there are several steps you can take, including: