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Is Glyphosate Weed Killer in Foods and Supplements Toxic?

How concerned should I be about glyphosate in foods and supplements?

Products that contain more than 1,100 micrograms (mcg) of the herbicide glyphosate per daily serving are required to have a warning label if sold in California, which has applied a fairly strict limit based on current science. The label warns that the product contains a chemical known to cause cancer and birth defects or other reproductive harm. This level of exposure is estimated to pose a 1 in 100,000 lifetime risk of cancer, as determined by the International Agency for Research on Cancer part of the World Health Organization. However, as discussed below, it seems unlikely that any food product will exceed this limit.  

In contrast, the European Food Safety Authority concluded that glyphosate is unlikely to pose a carcinogenic hazard (and that it does not have endocrine disrupting properties) but set a maximum acceptable daily intake limit based on reproductive toxicity shown in animal studies. The limit in Europe is currently set at 0.5 milligrams (or 500 mcg) of glyphosate daily per kilogram of body weight, which works out to about 34 milligrams, or 34,000 mcg, for a 150 lb person. The U.S. daily limit, set by the Environmental Protection Agency, is 3.5 times as high Europe's, although some have called for lower limit. 

Laboratory studies have shown that glyphosate can affect some bacteria that occur in the digestive system because it blocks a biochemical pathway for aromatic amino acid synthesis (the Shikimate pathway) that occurs in some bacteria (as well as in plants, but not in animals). However, short-term in vivo experiments in rats given high doses of glyphosate (equivalent to 50 times the European limit based on body weight) have only shown very limited effects, presumaby because of the abundance of amino acids in the gut that alleviate this biochemical effect (Nielsen, Environ Pollution 2018).

Glyphosate is the synthetic chemical in RoundUp herbicide, designed to kill weeds around plants that have been genetically altered to withstand it, such as genetically modified (GMO) soybeans and corn. It is also sprayed on many types of conventional crops such as wheat, oats, and barley prior to harvest as a drying agent and to even-out maturity. A USDA study in 2012 found that it was also commonly used on cherries, avocados, apples, lemons, grapefruit, peanuts, pecans, and walnuts ( Glyphosate is also found in processed foods containing these ingredients cannot be removed by washing, cooking, or baking. It can remain stable in food for a year or more.

Independent testing commissioned by the advocacy organization Food Democracy Now! and reported in November 2016 showed the concentrations of glyphosate in popular foods. The highest level was 1,125.3 ppb (or 1.1253 mcg per gram) in Original Cheerios. Based on this, a suggested serving of 28 grams of Original Cheerios would contain 32 mcg of glyphosate. This is much lower than California's 1,100 mcg warning level limit and far from the European daily intake limit of about 34,000 mcg for a 150 lb adult. Other breakfast cereals, such as Corn Flakes, Raisin Bran, Special K, and Wheaties contained less than one-tenth the amount in Original Cheerios. Although one might expect organic foods to be devoid of glyphosate, Food Democracy Now! actually found a higher concentration (119 ppb) of glyphosate in 365 Organic Golden Round Crackers than in most cereals, and even Kashi Organic Promise cereal contained glyphosate at 25 ppb, possibly due to cross-contamination of ingredients. The report notes that "...even organic farmers are having their crops/ our food contaminated."

The relatively high concentration of glyphosate in Original Cheerios is due to its main ingredient: whole grain oats. Independent testing shown in a 2016 presentation by and FDA scientist (see slide 30) found a similar level of glyphosate in other oat cereals, such as instant oatmeal packets, steel-cut oats, and infant oat cereal, although there was no detectable glyphosate in the organic oats it tested from Bob's Red Mill, 365 Whole Foods, Sprout, or Nature's Path.

Interestingly, tests by the Environmental Working Group (EWG) published in 2018 found a lower concentration of glyphosate in Cheerios (averaging about 500 ppb) than the earlier studies, although it found 390 ppb to 1,300 ppb in samples of Quaker Old Fashioned Oats. Samples of Bob's Red Mill Organic Old Fashioned Rolled Oats contained just 20 ppb or less and samples of Whole Foods Bulk Bin conventional rolled oats contained 40 ppb or less. Glyphosate in instant oat cereals ranged from no detectable amount in Simple Truth Organic Instant Oatmeal Original to around 700 ppb in Giant Instant Oatmeal Original Flavor and Quaker Dinosaur Eggs, Brown Sugar. EWG found no detectable glyphosate in an organic granola bar from Nature's Path, but 30 to 620 ppb in samples of other granola bars.

It's possible that dietary supplements containing grains, soy, fruits, and whole food supplements could contain glyphosate, as could supplements with other ingredients that are cross- contaminated with glyphosate from other sources. Again, however, it would be highly unlikely that the amount of glyphosate would exceed established safe limits, particularly as serving sizes for supplements are typically smaller than that of foods.

The bottom line: Glyphosate safe or unsafe?

Glyphosate is known to cause reproductive toxicity bases on animal models, and it may possibly be a carcinogen -- although there is dispute about this. Due to its widespread use as an herbicide, it is found in many foods. However, at standard serving sizes (and even several times those sizes) even foods with the highest known concentrations of glyphosate, such as conventionally grown oats, appear to contain amounts of glyphosate far below those that pose a safety risk or require any type of warning. However, if you are concerned,  glyphosate can be largely avoided by choosing organically-grown foods. However, be aware that "organic" processed foods, such as cereals, may still contain a very small amount of glyphosate, likely due to cross-contamination of ingredients. 

When evaluating reports on glyphosate, it is important to distinguish between the concentration in a product, typically in ppb (1,000 ppb = 1 mcg per gram), and how much you would consume, i.e., the concentration times the grams in a serving.

Also see's Oat Cereals Review, which compares amounts of ochratoxin A (a potential carcinogen and kidney toxin) and gluten in popular products. Glyphosate was not tested in the Review, which was conducted prior to the classification of glyphosate as a probable carcinogen in the U.S., but levels would likely be similar to those reported above.

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JoDell17093   August 20, 2018
I actually spoke with the on-staff veterinarian at Monsanto after my cat, and a friends dog (on the other side of town) both had bloody vomiting and bloody diarrhea with the only thing in common was that our husbands had sprayed roundup in the yard two days prior. Monsanto Vet told me no matter how long ago it has been sprayed the grass that it was sprayed on is NEVER safe to ingest by dogs, cats, cattle, horses, goats, etc.... Roundup is toxic and if my husband wants to remove weeds, grass or anything else, he now uses a propane torch to burn them. FYI - both the cat and dog died from cancer within 24 months. Yet people just keep on using it :(

Gigi17088   August 20, 2018
It would be helpful to know the effects to human health when exposed to smaller levels of this toxin over time. I don't think enough is being said about this lack of data. Therefore, down-playing the unlikely event someone would consume the limit of 1,100 mcg may be giving people a false sense of security that this toxin is not harmful, when in fact it might be.

vicki17115   August 28, 2018
The effects of a toxin tend to be different when exposure is acute (large dose over a short term) vs. chronic low level exposure which for humans can span decades. There is a lot of research on acute exposure trying to prove that glyphosate in our foods is safe, but very little has been done looking at the effects of exposure over a lifetime. The current increase in chronic metabolic issues such as obesity, diabetes, and autoimmune disorders suggests that this is a field of study that really should be pursued.

leeann 17087   August 20, 2018
Please be sure, when you mention choosing organic over conventional produce-that there are also organic pesticides. But the most important point is that, regardless of what has been used, none rise to the level of concern. The benefit of consuming fruits/vegetable/grains far outweighs the risk of danger from pesticides. Buy organic bc you like it (flavor, the way it's produced), not bc you fear danger from conventionally produced foods.
I am a registered dietitian concerned w people not getting the nutrients they need bc they believe conventionally grown foods are dangerous but cannot afford organic.

Martha17084   August 19, 2018
I have been warning anyone who would listen about glyphosates for years. Monsanto and the FDA say it is not toxic to humans, that it interferes with the organisms shikamate pathway, thereby killing it. As humans, we do not have this pathway; however, our friendly gut bacteria do and when consuming glyphosates, it will kill the friendly gut bacteria causing all sorts of problems - misdiagnosed Chrohn's Disease, Irritable Bowl Syndrome, etc. Wheat farmers, before harvest, will literally drown their wheat in glyphosates, causing them to produce more wheat berries in their dying frenzy. If it's conventionally grown wheat, it is toxic!!!   August 20, 2018
Thanks for mentioning this, Martha. It is correct that glyphosate can have a negative effect on certain bacteria, although experiments in animals given high doses of glyphosate so far seem to show only very limited effects. We've added information about this to our answer above. It is certainly an area that deserves attention and additional research.

Anna Angeline Angel17083   August 19, 2018
The conversation about glysophate is not a comprehensive one because it does not take into account, exposure to the chemical when the public uses parks, playgrounds & athletic fields!

In California some school districts spray RoundUp on the playgrounds & athletic fields.Communities use the chemical in park areas.

Anyone that resides near a sizeable farm that uses RoundUp
is likely to receive the chemical through the ‘drift' process.

When everything that a human or farm animals later processed as food, is taken into consideration, what are the exposure levels?

It's crucial to study all the factors that affect the food & beverages that may be consumed or absorbed through our environment!

Marsha16327   January 2, 2018
I can't believe there are still disbelievers in the science, given what we know about the toxicity of a chemical that is produced to kill. Many people have physiologies that do not allow them to detox these types of toxins easily or at all (I am one of them). The cumulative effect is what should be of concern. With the overload of toxins from all sources, our bodies can't keep up with the overload. What might be okay for some is harmful for others. Who wins?

Jeff16307   December 27, 2017
Some of the comments in this thread remind me of the same arguments made in the 1940's by cigarette manufacturers and their allies; that there wasn't enough poison in the average dosage of cigarettes to affect human health.

Just like the commenters back then, the people in this thread conveniently avoid talking about the cumulative effects of glyphosate and its long-term effects as well as wanting to err on the side of feeding poison to everyone while forcing people to prove that poison is dangerous.

They also fail to mention that the use of glyphosate only increases crop yields approximately 10%.

Their arguments are counterintuitive and exhibit a sociopathic tendency.

Robyn16207   November 15, 2017
Thank you to Consumer Lab for providing this article, the information you provide is greatly appreciated!

Stuart16198   November 13, 2017 should reconsider its "bottom line" that "glyphosate is a probable carcinogen." I doubt ConsumerLab has any evidence for this conclusion other than the IARC report from 2015, which is disputed by the vast majority of scientific findings around the world, including the very recent AHS finding, and which has also been called into serious question as a result of bias of a key participant. Unless there is other support that ConsumerLab can cite for this finding, to replicate the dubious conclusions of IARC risks perpetuating false beliefs that are contrary to science among your subscribers, and further jeopardizes the credibility of ConsumerLab (which I generally find to be excellent so far). It is very important that ConsumerLab reconsider and, as I urge, revise this conclusion for the sake of science and of the site's overall credibility.

Richard A16318   December 27, 2017
IARC is considered to be a very reputable and widely accepted source of information on carcinogens. Scientific risk determination is based on a weight of evidence approach, and the IARC, the AHS and all other studies and data must be considered together along with the quality of the studies themselves. Rarely is a single study considered alone when other evidence and studies are available. That being said, the jury is still out on glyphosate, its carcinogenicity and its other adverse effects.

Mike16193   November 12, 2017
I use glyphosate about once a year except for selective applications with a "weed wiper". Please show me actual proof that it causes cancer, the actual levels that it does, and a reasonable alternative, and I'll happily quit using it.

Anna Angeline Angel17187   September 20, 2018
It is your responsibility to search for the studies, the science & the political influence on this topic!

Jerry16189   November 12, 2017
This is all not true that is why people get cancer from it. They are all in bed and spread lies.   November 12, 2017
Hi Jerry - We are not "in bed" with any party here and are simply answering a good question with the current facts. We are all about providing solid, fact-based information. Our subscribers are largely individual consumers, and this is why they subscribe.

If information is published indicating more of a danger we will certainly include here.

In the meantime, it is certainly possible to largely avoid glyphosate if it is a concern by choosing foods not likely to contain it, as discussed above.

Mary16183   November 12, 2017
The above seems to be a very thoughtful and scientific article. Although each food item and/or supplement may not have enough glygosphate to be a concern, would there not be concernable amounts from a full day of food and supplements?   November 13, 2017
A good question. If you do the numbers, though, it seems highly unlikely that one could exceed the European limit. Assume that you ate exclusively the most contaminated oat cereal reported (1,670 mcg per gram in an instant oatmeal -- see the FDA presentation above) to provide all your energy, say 2000 Calories worth. That means you'd need to eat about 500 grams of food. This would yield about 8,350 mcg of glyphosate, which is still far below the European limit for an adult of around 34,000 mcg.

Steven16181   November 12, 2017
I'm surprised that California would set the limit so high, they should have placed it at Europe's level or below that.
Glyphosate is causing so many health problems and is toxic. Monsanto has caused more disease than any other comapny with it's glyphosate and GMOs.
In addition to a non GMO verified label we need a non glyphosate verified label.   November 12, 2017
The California limit is actually fairly stringent based on the current science.

Beverly17085   August 19, 2018
One question: If the level in "a" food is below the allowed limit, wouldn't all the various foods that a person would consume in a day be above the allowed limit?   August 20, 2018
Please see our answer to Mary's similar question above.

Douglas16179   November 12, 2017
Why is Consumer Labs not aware of this.

Previously unreported court documents reviewed by Reuters from an ongoing U.S. legal case against Monsanto show that Blair knew the unpublished research found no evidence of a link between glyphosate and cancer. In a sworn deposition given in March this year in connection with the case, Blair also said the data would have altered IARC's analysis. He said it would have made it less likely that glyphosate would meet the agency's criteria for being classed as “probably carcinogenic.”   November 13, 2017
Hi Douglas - We are aware of that article, which is interesting, but does not negate any information we presented above in our answer. For those who have not read it, the article indicates that research shows no association between exposure to glyphosate and non-Hodgkin lymphoma, based on a study of U.S. farm workers and their families.

Shelly17077   August 19, 2018
Just wondering what folks think about the Monsanto jury awarding $239 million to a landscape worker dying of lymphoma. They must have believed the data about glyphosate...   August 20, 2018
Hi Shelly - That case involved frequent occupational exposure via direct inhalation and skin contact. There is potential danger with this compound, but, like all things, it is a matter of dose, as well as route of administration.

Lyle17080   August 19, 2018
I agree with The IARC conclusion was partially based on supportive animal research, some of which showed genetic alterations related Glyphosate exposure. Such is a hallmark of cancer. Laura Beane Freeman from NCI will be publishing a more comprehensive review in relatively short time.

More generally I wonder out loud whether exposure by farm workers is really a good surrogate to lengthy low level ingestion by by consumers. Could be but I do not recall that this has been clarified (I have not read the original research).

LMA, Durham NC

Martha16178   November 12, 2017
Glyphosates kill weeds by disrupting their shikamate pathway; Monsanto's claim that humans do not have this pathway was one of the arguments that ultimately caused the FDA to approve this poison. Directly, humans do not; however, the friendly little bacteria in our gut does and if you eat glyphosates, you will kill them. I know; it happened to me. After two years of intestinal problems, I went totally organic and it has totally cleared up.

Eileen16311   December 27, 2017
Thanks for your insight. I also agree that the jury is out on this one, and to be safe, we should be trying to stay away from it. I stopped using it even on weeds 3 years ago and got a "blow torch" for them instead.

Stuart16177   November 12, 2017
The only body in the world to conclude that "glyphosate is a probable carcinogen" is IARC. The integrity of IARC's report and conclusions has been prominently called into question. Not only EFSA but also EPA, the Canadian Pesticide Management Regulatory Agency, and others have concluded directly to the contrary that glyphosate is not a carcinogen. In addition, the Agricultural Health Study, conducted under the auspices of the National Cancer Institute, EPA and other bodies since 1993, reported on November 9 that there are no significant associations between glyphosate and incidences of cancer in a population of 89,000 farmers and their spouses. The "bottom line" should not be that "glyphosate is a probable carcinogen", but rather the IARC's conclusion (and the California listing which relies solely on the IARC report) is a politically-motivated outlier.

Al16206   November 15, 2017
The may be quite a bit more to it than whether it's a carcinogen. And politics do cut both ways, otherwise there wouldn't be lobbyists.

This CL Answer initially posted on 11/11/2017. Last updated 8/16/2018.

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