What Food Has the Most Glyphosate? A Guide to Contamination in Your Diet

October 4, 2025 •

5 min read

Studies by the Environmental Working Group (EWG) have revealed widespread contamination, with over 95 percent of popular oat-based food samples testing positive for the herbicide. This leads many to question: what food has the most glyphosate and how does it affect our diet?

Quick Summary

Grains and legumes are frequently contaminated with glyphosate, especially non-organic oats, wheat, and chickpeas due to pre-harvest spraying. Processed foods and cereals made from these crops often contain residues, making organic alternatives a key strategy for reducing exposure.

Key Points

Top Contaminated Foods: Non-organic oats, wheat, corn, soy, chickpeas, and lentils are frequently found to have the highest levels of glyphosate residues.
Pre-Harvest Desiccation: The practice of spraying crops like oats, wheat, and legumes just before harvest to dry them out is a major cause of high glyphosate residues.
GMO Crops and Glyphosate: Genetically modified crops, such as most corn and soybeans, are engineered to tolerate heavy glyphosate application, contributing significantly to overall exposure.
Organic is Key: Buying certified organic versions of high-risk foods is the most effective way to reduce dietary intake of glyphosate, as its use is prohibited in organic farming.
The Regulatory Debate: Health agencies like the IARC and the EPA hold conflicting views on the carcinogenicity of glyphosate, leading to ongoing scientific debate and differing safety assessments.
Washing is Not Enough: Glyphosate is a systemic herbicide, meaning it is absorbed into the plant tissue, so washing produce will not remove the chemical.

Understanding Glyphosate Contamination

Glyphosate is a widely used, broad-spectrum herbicide, famously sold under the brand name Roundup®, that is used to control weeds in agriculture and residential areas. There are two primary ways that glyphosate ends up in our food. First, it is used heavily on genetically modified (GM) 'Roundup Ready' crops like soy and corn, which are engineered to tolerate the chemical while weeds are eliminated. Second, and a major cause of high residues in certain foods, is the practice of pre-harvest desiccation. This involves spraying non-GMO crops such as oats, wheat, and legumes just before harvest to kill and dry them out, allowing for an earlier and more uniform harvest.

Residues from this process can be found in a wide variety of foods. While regulatory bodies like the U.S. Environmental Protection Agency (EPA) set Maximum Residue Limits (MRLs) for food and maintain that residues are safe at these levels, independent organizations often report levels that exceed their own stricter health benchmarks. This has led to ongoing debate and heightened consumer awareness about what's in our food supply.

The Foods with the Highest Glyphosate Levels

Recent reports from organizations like the Environmental Working Group (EWG) and Canadian Food Inspection Agency (CFIA) have shed light on the most heavily contaminated food categories.

Oats and Other Grains

Conventionally grown oats are one of the most frequently cited examples of glyphosate contamination due to pre-harvest desiccation. Studies found that a large percentage of oat products contain residues, with some cereals and granola bars showing particularly high levels.

Breakfast cereals: Iconic oat-based cereals have tested positive for high levels of glyphosate residues, sometimes significantly exceeding health benchmarks suggested by groups like EWG.
Granola bars and instant oats: These processed oat products are also frequently contaminated, posing a significant exposure source, especially for children who consume them regularly.
Wheat products: Glyphosate is also used as a pre-harvest desiccant on wheat. Tests on products like pasta, crackers, and bread have found widespread contamination. A 2019 report by EWG detected glyphosate in all 12 wheat-based products tested.

Legumes and Pulses

Chickpeas, lentils, and beans are other crops where desiccation is commonly used, leading to notable residue levels. The high protein content of these foods also means they can absorb more of the herbicide.

Hummus: EWG testing on hummus and chickpea products found over 80% of conventional samples contained glyphosate. Some conventional hummus brands showed levels nearly 15 times EWG's health benchmark.
Dried legumes: Tests have revealed glyphosate in dry chickpeas and lentils, with some samples containing very high concentrations.

Genetically Modified Crops

Soybeans and corn are heavily treated with glyphosate throughout their growing season due to their genetic modification for herbicide resistance. A 2018-2019 FDA report showed that over half of the conventional corn and soy samples tested contained residues.

Soy-based foods: This includes soy milk, tofu, and meat alternatives. Studies have found that while some soy varieties contain no glyphosate, GM soy can have significant residues.
Corn-based products: Residues can be found in cornmeal, chips, and processed foods that use corn as an ingredient.

Health Effects and Regulatory Debate

Determining the health impact of long-term, low-level glyphosate exposure is a topic of scientific debate. The primary point of contention lies in differing interpretations of available evidence by various health and regulatory bodies.

Conflicting Classifications

World Health Organization (WHO): In 2015, the International Agency for Research on Cancer (IARC), an arm of the WHO, classified glyphosate as 'probably carcinogenic to humans,' leading to numerous lawsuits and public concern.
U.S. Environmental Protection Agency (EPA): The EPA concluded in 2020 that glyphosate is 'not likely to be carcinogenic to humans' when used according to its label, a finding at odds with the IARC assessment. The EPA's conclusion has faced legal challenges.
European Food Safety Authority (EFSA): Like the EPA, the EFSA found no critical areas of concern that would prevent the renewal of glyphosate's approval.

Potential Health Concerns

Despite the regulatory debate, some studies point to potential risks associated with glyphosate exposure, particularly through dietary intake. Concerns often highlighted by independent scientists and public health advocates include:

Gut Microbiome Disruption: Some research suggests glyphosate can affect gut bacteria, with potential downstream effects on neurological, behavioral, and immune functions.
Endocrine Disruption: In vitro studies have indicated that glyphosate can cause endocrine disruption, which may affect the hormonal system.
Increased Cancer Risk: Some epidemiological surveys have reported increased risks for specific cancers, such as non-Hodgkin's lymphoma, in highly exposed agricultural workers.

How to Minimize Your Exposure

Reducing your intake of glyphosate can be a part of a wider nutritional strategy to minimize exposure to pesticides and other chemicals. Since glyphosate is a systemic herbicide, simply washing produce is often not sufficient to remove all residues.

Choose organic products: This is the most effective way to avoid glyphosate, as its use is prohibited in organic farming. While some organic products may contain trace amounts from environmental drift, levels are significantly lower than in conventional alternatives.
Look for 'Glyphosate Residue Free' labels: Third-party certifications, such as those from The Detox Project, test products to ensure they contain no detectable glyphosate residues.
Prioritize whole foods: Opt for fresh, unprocessed fruits and vegetables whenever possible. This gives you more control over the food on your plate.
Buy local and ask questions: Sourcing food from local farmers' markets may allow you to speak directly with growers about their agricultural practices and use of herbicides.
Focus on high-risk items: If buying everything organic is not feasible, prioritize purchasing organic versions of the foods most likely to contain high residues, such as oats, legumes, corn, and soy.

Comparison of Conventional vs. Organic for High-Risk Foods


Food Category	Conventional Glyphosate Contamination	Organic Glyphosate Contamination	Key Difference	References
Oats	Widespread detection, often with high levels due to desiccation.	Significantly lower levels, though some trace amounts may occur due to environmental drift.	Organic farming prohibits glyphosate use; contamination in organic is minimal and unintentional.
Wheat	High prevalence in products like pasta, bread, and cereals due to desiccation.	Very low or non-detectable levels, as organic standards prohibit glyphosate.	Desiccation is not used on organic wheat; the primary source of high residue is eliminated.
Chickpeas	High levels found, especially in products like hummus, due to pre-harvest spraying.	Lower levels detected in some organic samples, but significantly less than conventional.	Organic chickpea products show substantially less residue, though some traces exist.
Soy	Heavy use on GM 'Roundup Ready' crops leads to high residue levels.	No glyphosate was found in some organic soy samples tested.	Genetically modified soy is designed to withstand glyphosate, leading to heavy application; organic soy is not GM.

Conclusion

While the regulatory status and specific health implications of dietary glyphosate exposure are still under debate, evidence from independent testing shows certain foods are far more likely to contain high residue levels than others. Conventionally grown grains like oats and wheat, legumes such as chickpeas and lentils, and GMO crops like soy and corn consistently appear on lists of the most contaminated foods, largely due to pre-harvest spraying practices. For consumers concerned about minimizing their exposure, choosing certified organic versions of these high-risk products is the most effective and direct strategy. By making informed dietary choices, it's possible to significantly reduce your daily intake of this pervasive herbicide.

For more detailed information on avoiding pesticide exposure, you can consult resources like the EWG's Guide to Avoiding Glyphosate in Food.

Frequently Asked Questions

No, eating organic does not guarantee zero exposure. While glyphosate is prohibited in organic farming, organic crops can still have trace amounts of residue from spray drift from nearby conventional fields. However, residue levels are significantly lower than in conventional products.

Washing can help remove surface pesticide residues, but glyphosate is a systemic herbicide. This means it is absorbed into the plant tissue, and washing will not effectively remove it.

Not necessarily. The residue levels depend on application rates and timing. However, since GM crops like corn and soy are engineered to resist glyphosate, they are typically sprayed heavily with the herbicide, often resulting in higher overall residue levels compared to non-GMO alternatives.

Pre-harvest desiccation is the practice of spraying certain crops, such as oats, wheat, and legumes, with an herbicide like glyphosate just before harvest. It kills and dries the plants to speed up the harvesting process and ensure a uniform crop maturity.

The EPA performs a risk assessment, concluding that current glyphosate levels are not carcinogenic. The IARC, an arm of the WHO, conducts a hazard assessment, classifying glyphosate as 'probably carcinogenic to humans' under some circumstances. This difference in methodology leads to conflicting conclusions.

Yes, glyphosate has been found in conventional animal feed, particularly alfalfa and barley. While FDA tests on products like milk and eggs have not found residues above tolerance levels, some studies raise questions about potential accumulation or transfer of glyphosate into the food chain.

The most effective way is to prioritize organic versions of high-risk items like oats, wheat, legumes, corn, and soy. Look for 'Glyphosate Residue Free' labels and consider purchasing unprocessed whole foods from local growers.