Corn is the most used ingredient in pet food. In all its variations from corn gluten meal to corn syrup to plain old corn, it outweighs the 2^nd most used ingredient by more than three to one.  Corn along with about a dozen other crops receives the bulk of all agricultural chemicals used in the US.  Let’s talk about one of those chemicals used in the field.  It has a particularly devastating impact on the gut.

The connection between the gut and health

The microbiome is a virtual organ connecting itself in a multi-faceted and fascinating way to health.  At 10¹⁴ gut bacteria vs 10¹³ cells in the body, four major phyla, and about 100 times the genes in gut flora than the genome, the microbiome is the most densely populated ecosystem on Earth.

Science has shown that a single commensal bacterium in gut flora can modulate gene expression involving nutrient absorption, gut mucosal barrier fortification, xenobiotic metabolism (think detoxification), intestinal maturation, and immune system development.

The connection between glyphosate and chronic disease

In the US and globally, reports of chronic disease in humans have skyrocketed over the last 20 years.

The herbicide glyphosate was introduced in 1974 and its use accelerated with the advent of GMOs.  In 1990, the US began using glyphosate on many crops (not just GMOs) as a desiccant and to ripen them just before harvest.

A third of US crop land - nearly 300 million acres - is treated with glyphosate at an average rate of about a pound of glyphosate per acre.

In the US, 85% of glyphosate is applied to the nutritional crops that make up 96% of all the plant-based ingredients that pet food manufacturers use: soy, field corn (also called feed grade corn), wheat, rice, dried beans and peas like lentils, sugar, beets, peanuts, canola, sorghum, barley, potatoes (white, yellow, red and russet – not sweet potatoes), and sunflower products.   

The USA has some of the highest permissible levels for glyphosate worldwide – at 1.75 mg/kg of bodyweight daily.  That’s 3.5x the acceptable daily intake (“ADI”) in Canada and nearly 6x the ADI in Europe.  Remember that: 6 times.

The glyphosate residues permitted on feed grade grains and plants that pets eat can be anywhere from 30 to 100 times greater than what is permissible on human food.  And that’s assuming regulatory enforcement of animal feed.  (Hint: there’s reason for alarm about a lack of regulatory enforcement.)

In 2015 the World Health Organization called glyphosate a probable human carcinogen.  Though the EPA does not yet acknowledge glyphosate’s carcinogenic potential, Bayer (Monsanto) has paid approximately $11 billion to date to settle about 100,000 lawsuits related to Roundup (an herbicide containing glyphosate).

In 2017, the results of a 2-year study showed ultra-low doses (.1 ppb) of glyphosate formulations fed to rats were linked to an increased likelihood of developing non-alcoholic fatty liver disease.

Glyphosate is a weed killer of the microbiome

Then an amazing thing happened.  In 2021, 13 researchers in Europe showed in an animal study that glyphosate and its products like Roundup administered within Europe’s ADI for humans disrupts the balance of gut bacteria through the same shikimate pathway it destroys weeds. 

Glyphosate has been shown to destroy beneficial gut bacteria creating opportunities for pathogenic bacteria  – which are glyphosate resistant.  Salmonella and clostridium are highly resistant to glyphosate, whereas bifidobacteria, enterococcus, and lactobacillus are especially susceptible.

 Analysis of gut and blood biochemistry shows that glyphosate and more dramatically RoundUp, cause oxidative stress, which associates these chemicals with DNA damage and cancer.

At about this same time, researchers in another study out of Finland said that they were able to determine, in a “conservative estimate,” that approximately 54 percent of the species in the core of the human gut microbiome are “potentially sensitive” to glyphosate.

In 2014, a massive correlational study was conducted. It searched US government databases for genetically engineered crop data, glyphosate application data and disease epidemiological data. Analyses were then performed on a total of 22 diseases in time-series data sets.  The video below shows their results.

The red line you'll see in the graphs in the video indicates glyphosate application. The blue line indicates GMO crop data.  Where possible, you’ll also see a green line indicating the disease trend prior to 1990.

These results show a highly significant correlation between glyphosate application and increases in certain chronic diseases namely:  cancers of the thyroid, liver, bladder, pancreas, and kidney, as well as myeloid leukaemia;  also diabetes, end stage renal disease, acute kidney failure, obesity, lipoprotein metabolism disorder, inflammatory bowel disease, intestinal infections, autism, Alzheimer’s disease, senile dementia, Parkinson’s, multiple sclerosis, stroke, and hypertension.

No doubt, there are a lot of questions that need to be asked and answered about glyphosate.  An important one is this:

How much glyphosate is contaminating pet food? 

The answer is tough to say.  Big pet food manufacturers – if they are testing for it – are not publishing the results.  Neither are state agricultural regulators. 

A search on the FDA recall database echoes this deafening silence.  Despite nearly 500 recalls of human foods for high levels of agricultural chemicals including glyphosate, the FDA has never issued a single recall of a pet food for any agricultural chemical exceeding the permissible level.  Not one.

The only study on glyphosate in pet food that we could find was a small 2018 study out of Cornell that looked at 18 commercial pet feeds from eight manufacturers.  This represents less than 1% of the US market.  They found glyphosate in all of them – even the “organic” variety.   Their study showed that higher carbohydrate foods had more glyphosate.  The concentrations in the most offensive products in their study were estimated to result in exposures on a per mg/kg basis that are 4–12 times higher than humans.

HRI is a lab that conducts glyphosate exposure testing on humans and pets based on urine samples.  They report that the average glyphosate levels in canine urine are 14 ppb (about 28 times higher than what they typically see in humans).  But there could be sampling bias in their findings, as most pet parents who would test their dog’s urine for glyphosate are probably more health conscious than the average person.  These parents could arguably be feeding their dog a cleaner diet than the average dog who eats a conventional kibble or canned feed.  If this were the case, then the glyphosate levels in the general population of US dogs may be even higher.

How can you reduce your dog’s exposure to glyphosate? 

The first step would be to avoid buying a pet food that contains any of the conventionally grown crops below:

Glyphosate levels tend to be high in some outdoor water sources – like puddles and streams.  So discouraging your dog from drinking from these places can help.  Exercising your dog on wooded trails instead of parks or playgrounds where RoundUp is used may reduce exposure.

Be wary of the “Organic” trap in pet food too.  There is no official “organic” definition or standard in pet food.  The only time “organic” pet food ingredients are regulated to the same standard as human food is when the organic ingredient goes into a human grade pet food.   Organic ingredients in conventional (i.e non-human-grade) pet feeds are not enforced, and their labeling claims are allowed to mislead consumers.

At Goodness Gracious, we make human grade pet food that focuses on non-GMO, clean produce.  Some of our ingredients – like our sprouted sunflower seeds – are organic. We’ve also tested our own dogs for the glyphosate levels in their urine.  We are pleased to report that the most recent results are just around 1 ppb – which is about as good as it gets for the active, outdoorsy types of canines.

Human grade pet foods that use organic ingredients can be expensive -- especially for families with big dogs.  But remember, you don't have to go "all in."  Replacing as little as 10% - 20% of a processed pet feed diet with clean, whole foods has a positive impact on a dog's body.  Just 10%.