Because glyphosate targets an enzyme found in plants but not in animals, it was long considered safe for use on foods consumed by humans. But is it really harmless? Read on to learn how glyphosate can be damaging to our health, how glyphosate impacts the environment, and if gluten intolerance could instead be a symptom of glyphosate exposure.
Glyphosate is routinely used on wheat, corn, and soy as a weed killer—and could carry serious consequences for your health. Find out what the research says about glyphosate and its impact on human health. #wellness #chriskresser
What Is Glyphosate?
Monsanto patented glyphosate under the name “Roundup” in the 1970s, and soon after it was approved as a weed killer to be applied before planting and also for weed control in pastures and non-crop areas. (2) In 1996, Monsanto released the first “Roundup Ready” soy crop that was genetically modified to be resistant to Roundup. In 2000, the year glyphosate became generic (and therefore cheaper), farmers applied around 90 million pounds of glyphosate. By 2014, glyphosate application reached 240 million pounds. (3, 4) With more GMO crops sprouting up across the globe, glyphosate usage is expected to keep rising.
Like other herbicide residues, as well as residues from pesticides, glyphosate and its metabolites can make their way into our soil, waterways, food made with treated crops, and meat and dairy from livestock that were fed those crops. (5) Glyphosate even shows up in our urine. (6)
Six Damaging Roles Glyphosate Herbicides Can Potentially Play in Your Body
As an herbicide, glyphosate works by disrupting EPSPS, a specific plant enzyme in the shikimate pathway, resulting in protein shortage and eventual death. (14) Plants, algae, bacteria, and fungi all have the shikimate pathway, but animals do not. Therefore, glyphosate was considered safe and non-toxic for humans in theory, but increasing evidence challenges this original view.
1. A Probable Carcinogen
In 2015, over 40 years after glyphosate was first approved, the World Health Organization’s International Agency for Research on Cancer declared glyphosates as “probably carcinogenic to humans” based on both human epidemiological data and controlled rodent studies. (15)
2. Gut Microbiome Disruptor
Glyphosate disrupts the shikimate pathway in our gut bacteria. Pathogenic strains of gut bacteria, like Salmonella and Clostridium, were resistant to glyphosate exposure, while glyphosate attacked beneficial strains like Enterococcus, Bacillus, and Lactobacillus. (16, 17, 18) Glyphosate may even compromise antibiotics’ ability to fight pathogenic E. coli and Salmonella. (19) Gut dysbiosis is linked to many health problems, including obesity, Alzheimer’s disease, autism, ADHD, type 2 diabetes, Crohn’s disease, and IBD … just to name a few. (20, 21, 22, 23, 24, 25, 26, 27)
3. Cytochrome P450 Enzyme Disruptor
At high levels, glyphosate inhibits key enzymes—including the cytochrome p450 enzyme—in human, plant, and rodent cells. (28, 29, 30) Cytochrome p450 enzyme disruption has also been demonstrated in rodent glyphosate feeding studies. (31, 32, 33) This class of enzymes influences many cellular processes, including: (34)
- Detoxification of foreign substances
- Cholesterol and vitamin D3 synthesis and degradation
- Conversion of testosterone into estrogen
We need more research to determine if these disruptions can affect detoxification, hormones, and/or nutrition.
4. Endocrine Disruptor
Some research suggests that glyphosate herbicides may act as endocrine disruptors, chemicals that interfere with the body’s normal hormone signaling pathways. BPA is probably the most well-known endocrine disruptor on a growing list. Endocrine disruptors are insidious; they wreak havoc over time at very low levels, in contrast to acute toxicity studies performed at high levels of exposure. (35)
Cell experiments have shown that glyphosate-based herbicides interfered with estrogen and androgen receptors and also with aromatase, the enzyme that converts testosterone into estrogen. (36, 37, 38) Glyphosate was also shown to induce human breast cancer cell proliferation via estrogen receptors. (39)
5. Mineral Chelator
Glyphosate chelates minerals like copper, magnesium, cobalt, iron, zinc, calcium, and magnesium, which could prevent proper absorption and utilization of these minerals in the body. (40) Nearly one-third of American adults and children are already at risk for at least one nutrient deficiency, and many of these minerals are enzymatic cofactors for normal cellular functions. (41) Glyphosate potentially could contribute to mineral deficiencies. Enough mineral deficiency could even lead to chronic kidney disease. (42)
6. Oxidative Stressor
Oxidative stress occurs when the production of free radicals or reactive oxidative species (ROS) exceeds the body’s ability to neutralize them. Enough oxidative stress can damage cells, proteins, and DNA, contributing to the development of cardiovascular disease, autoimmune disease, and other chronic diseases. (43, 44, 45, 46)
Rodents drinking glyphosate dissolved in water at the “highest allowable” level for three months had increased lipid peroxidation and glutathione peroxidase, both indicators of oxidative stress. (47) Other in vivo and in vitro studies have also shown that glyphosate induces oxidative stress. (48, 49, 50, 51, 52)
See for Yourself: How to Fish through a Sea of Studies
If you’d like to dive deeper into whether or not herbicides containing glyphosate are harmful to humans, I encourage you to take a look at the research that’s out there. Fair warning, though: it’s a popular topic. If you search for research on “glyphosate toxicity,” nearly a thousand peer-reviewed studies appear.
Who Funded the Study?
Industry-funded studies are more likely to yield favorable results and more likely to be published. (53, 54) Glyphosate is no exception. Many industry-funded studies and reviews have found no health concerns with glyphosate, while most of the studies that proposed adverse health effects were not industry funded. (55, 56, 57, 58, 59)
What Was the Study Duration?
Rats exposed to glyphosate for 90 days may not have revealed any health concerns (although that is still up for debate), but when rats were exposed to glyphosate for longer periods of time, results showed higher mammary tumor incidence and the development of liver and kidney problems. (60, 61, 62, 63)
Which Herbicide Formulation Was Used?
Glyphosate is just one ingredient in Roundup. Glyphosate-based herbicide formulas also contain additional ingredients, which enhance the effectiveness of glyphosate. Some components of these enhancing ingredients, such as 1,4-dioxane, are known carcinogens. (64) Chemicals studied individually cannot always predict how chemicals in combination will affect an organism. (65)
What Dose Was Delivered?
What happens after a high-dose, short-term exposure doesn’t necessarily reflect the health effects of a chronic low dose over a lifetime. Endocrine disruption works this way—it doesn’t generate a linear dose-response curve, and sometimes a low dose invokes the opposite effect compared to a high dose! More studies are demonstrating harmful effects of glyphosate when administered at lower doses over a long period of time. (66, 67)
Is Your Gluten Intolerance from Non-Celiac Wheat Proteins … or from Glyphosate Residue?
Recently, farmers started applying an extra dose of Roundup to wheat right before harvest, as a “pre-harvest desiccant.” Some people wonder if their perceived non-celiac gluten sensitivity (NCGS) is actually their bodies responding to the high glyphosate levels. I suppose it’s possible. However, many people who have NCGS find symptom relief once they stop eating gluten but presumably still eat other glyphosate-containing foods like corn, soy, etc., which would seem to disprove this theory.
If the two are related, it’s probably through the gut and would look something like this: glyphosate could disrupt the gut microbiome, which could eventually damage the gut lining, which would then allow gluten-related proteins to pass into the bloodstream, and the immune system would respond and become sensitive. In these cases, people would indeed find relief if they stopped eating gluten, but they would be sensitive to the gluten proteins, not the glyphosate.
One peer-reviewed yet highly contested article proposes something quite similar to this, claiming that both celiac disease and NCGS could originate from glyphosate. (68) Regardless of glyphosate’s link to gluten issues, I believe we have enough evidence to warrant avoiding it.
These Herbicides Carry an Environmental Impact, Too
Glyphosate’s effects extend beyond human health into the environment. Negative environmental impacts include:
- Development of glyphosate-resistant weeds, leading to further increased applications of glyphosate and/or other herbicides (69, 70, 71)
- Contributing to the declines in butterfly and honeybee populations, affecting pollination of plants (72, 73)
- Toxicity to aquatic life, including algae, invertebrates, fish, and amphibians, potentially threatening entire ecosystems (74)
- Threats to soil health and fertility (75, 76, 77)
How to Avoid Glyphosate (and Other Toxins)
Sadly, glyphosate is merely one of the hundreds of environmental toxins we’re exposed to on a daily basis. We just don’t know the long-term health and environmental consequences of being exposed to cocktails of man-made chemicals throughout a lifetime.
Avoid environmental toxins, including glyphosate, by:
- Eating organic—it really is better
- Avoiding plastics that contain harmful chemicals like BPA and plasticizers
- Switching your cosmetics and personal care products to greener and more natural varieties
- Installing a water filter and home air purifier
- Cleaning your home with less harsh products
- Testing your home for mold