Toxic Legacy: How the Weedkiller Glyphosate Is Destroying Our Health and the Environment

In the previous five years, I’d been on a dogged journey to identify environmental factors that might be causing the increase in autism among America’s children. Characterized by social deficits, repetitive behaviors, and impaired cognitive abilities, autism spectrum disorder can present as relatively mild, or it can be extreme, requiring full-time lifelong care. Like many scientists, I’d noticed that the rates of autism spectrum disorders had been rising dramatically over the past few decades, in ways that could not be accounted for by diagnostic criteria. Based on a survey conducted by the United States Health Resources and Services Administration (HRSA) in 2016, the prevalence of autism in the United States is about 1 in 40 children.¹ According to the Centers for Disease Control and Prevention, the prevalence of autism among 12-year-old children is about 1 in 54, and it is four times more common among boys than among girls.²

By the time I attended Dr. Huber’s presentation on glyphosate, I had already learned a great deal about the complicated medical conditions that often accompany autism, including a disrupted gut microbiome, inflammatory and leaky gut, nutrient malabsorption, food sensitivities, vitamin and mineral deficiencies, and impaired methylation and sulfation pathways. I had been assiduously studying the toxic effects of various metals and chemicals in the environment: mercury, fluoride, lead, aluminum, plastics, polychlorinated biphenyls, polysorbate 80, and other endocrine disruptors and carcinogens. I was also investigating the role of diet and the overuse of antibiotics. I was trying to find something in the environment that had become more pervasive in the past two decades, in step with the dramatic rise in autism rates, that might explain the diverse symptoms associated with the brain dysfunction we were seeing.

What I learned from Dr. Huber is that glyphosate is the active ingredient in the herbicide Roundup. While glyphosate isn’t a household name, everyone has heard of Roundup. Drive across the United States and you’ll see vast fields marked with crop labels that say “Roundup Ready.” Monsanto, the Missouri-based company that was Roundup’s original manufacturer, was acquired by the Germany-based company Bayer in 2018 as part of its crop science division. Monsanto has touted glyphosate as remarkably safe because its main mechanism of toxicity affects a metabolic pathway in plant cells that human cells don’t possess. This is what—presumably—makes glyphosate so effective in killing plants, while—in theory, at least—leaving humans and other animals unscathed.

But as Dr. Huber pointed out to a rapt audience that day, human cells might not possess the shikimate pathway but almost all of our gut microbes do. They use the shikimate pathway, a central biological pathway in their metabolism, to synthesize tryptophan, tyrosine, and phenylalanine, three of the twenty coding amino acids that make up the proteins of our body. Precisely because human cells do not possess the shikimate pathway, we rely on our gut microbiota, along with diet, to provide these essential amino acids for us.

Perhaps even more significantly, gut microbes play an essential role in many aspects of human health. When glyphosate harms these microbes, they not only lose their ability to make these essential amino acids for the host, but they also become impaired in their ability to help us in all the other ways they normally support our health. Beneficial microbes are more sensitive to glyphosate, and this causes pathogens to thrive. We know, for example, that gut dysbiosis is associated with depression and other mental disorders.³ Alterations in the distribution of microbes can cause immune dysregulation and autoimmune disease.⁴ Parkinson’s disease is strongly linked to a proinflammatory gut microbiome.⁵ As has become clear from the remarkable research conducted on the human microbiome in the past decade or so, happy gut bacteria are essential to our health, including in ways that researchers have yet to fully understand. It’s worth remembering that Roundup hit the market—and was declared safe—before much of this groundbreaking research on the human microbiome was ever conducted.

Dr. Huber also explained that glyphosate is a chelator, a small molecule that binds tightly to metal ions. In plant physiology, glyphosate’s chelation disrupts a plant’s uptake of essential minerals from the soil, including zinc, copper, manganese, magnesium, cobalt, and iron. Studies have shown that plants exposed to glyphosate take up much smaller amounts of these critical minerals into their tissues.⁶ When we eat foods derived from these nutrient-deficient plants, we become nutrient deficient, as well.

Glyphosate also interferes with the symbiotic relationship between plant roots and soil bacteria. Surrounding the roots of a plant is a soil zone called the rhizosphere that is teeming with bacteria, fungi, and other organisms. As I will explain later in more detail, glyphosate kills the organisms living in the rhizosphere, which then interferes with a plant’s nitrogen uptake, as well as the uptake of many different minerals.⁷ This interference further translates into mineral deficiencies in our foods. Glyphosate also causes exposed plants to be more vulnerable to fungal diseases.⁸ And fungal diseases can lead to contamination of our foods with mycotoxins produced by pathogenic fungi.

I came away from Dr. Huber’s lecture convinced that I needed to learn a lot more about glyphosate.

When I earned my PhD in 1985, I accepted a job as a research scientist at MIT, and I began a career developing multimodal dialogue systems to facilitate “natural” conversational interaction between humans and computers. Our research involved constructing interactive demonstration systems that were precursors to products like Apple’s Siri and Amazon’s Alexa. We also designed and developed dialogue-based computer games to help students master a second language, and we specifically focused on English-speaking students learning Chinese. I’ve worked to enrich people’s lives using technology, to improve access to information, and to provide entertaining ways to advance language skills. Over time, I was promoted to principal research scientist and ultimately senior research scientist, the highest level on the research track at MIT.

Since 2008, I have brought my expertise in statistical analysis, computational modeling, and biology to investigate the impact of nutritional deficiencies and environmental toxicants on human health, including Alzheimer’s disease, cardiovascular disorders, immune dysfunction, and neurological disorders. I have now published more than three dozen peer-reviewed scientific papers on health-related topics. I have been researching, writing about, and lecturing on glyphosate for nearly a decade. The book you hold in your hands is a culmination of that research.

As we’ll explore together, there is a growing body of scientific evidence that shows that glyphosate is a major factor in several debilitating neurological, metabolic, autoimmune, reproductive, and oncological diseases. This organic chemical compound—C₃H₈NO₅P—is much more toxic to all life forms than we have been led to believe. Glyphosate’s mechanism of toxicity is unique and diabolical. It is a slow killer, slowly robbing you of your good health over time, until you finally succumb to incapacitating or life-threatening disease. Its insidious, cumulative mechanism of toxicity, which begins with the seemingly simple substitution of glyphosate for the amino acid glycine during protein synthesis, explains the correlations we are seeing with diverse diseases that seem to have little in common.⁹

In the 1940s and 1950s, Americans were told that herbicides and insecticides, such as DDT, were safe. DDT is an organochloride first used by the military during World War II to control body lice, bubonic plague, malaria, and typhus.¹⁰ While DDT was effective at preventing malaria, the environmental consequences of its use were devastating, especially as people began using it more and more, in broader and broader applications, for pest control.

I read Rachel Carson’s book Silent Spring in 1962, shortly after it was published. A marine biologist by training, Carson condemned the chemical industry for its irresponsible disinformation campaign. She painted a grim picture of no birds singing in the spring. She called it “fable for tomorrow,” a phrase that haunts me to this day. Silent Spring explores in detail how DDT and other chemicals were poisoning wildlife—from earthworms in the soil to juvenile salmon in the rivers and oceans. Carson’s book had a profound effect on me and helped me understand my grandfather’s untimely and unexpected death.

Around the same time, I also learned about the thalidomide disaster. Thalidomide, manufactured by a German pharmaceutical company, was prescribed to pregnant women to help with morning sickness and difficulty sleeping. It was aggressively marketed and advertised as safe. But thousands of children whose mothers took thalidomide during pregnancy were born with birth defects, including missing arms and legs. Studying the photographs of these deformed and unhappy children in a magazine, I realized that sometimes the products that purport to improve our lives can have major adverse effects—and that the companies that sell them cannot necessarily be trusted to tell us the whole truth about the risks their products pose.

The United States avoided this disaster, which devastated the lives of at least 10,000 children in Europe, because of a brave scientist named Frances Oldham Kelsey. Dr. Kelsey was a Canadian-born reviewer for the US Food and Drug Administration, responsible for approving or rejecting the application for a license to distribute the drug in the United States. Although she faced enormous pressure, and although thalidomide was already approved for use in Canada, Great Britain, and Germany, Dr. Kelsey rejected the application after she determined that there was insufficient evidence that it was safe to use during pregnancy.¹¹ At the time, I was young, optimistic, and patriotic. I remember thinking how lucky I was to live in the United States, a country that protected its citizens from such a catastrophe.

Yet, there’s no question that something devastating is going on, even if it’s difficult to name it precisely. The rate of species going extinct today is hundreds or even thousands of times faster than it has been during the past tens of millions of years. Environmental scientists warn that we have already entered the sixth mass extinction.¹³ Human health is also suffering. Over the past few decades an alarming rise in many chronic diseases across the globe has occurred, especially in countries that adopt a Western-style diet based on industrialized agriculture. Many of these diseases have an autoimmune component. They include Alzheimer’s disease, autism, celiac disease, diabetes, encephalitis, inflammatory bowel disease, and obesity.

Something terrible seems to be affecting every living thing on the planet—the insects, the animals, and the health of human beings, including children. Something hiding in plain sight. While we can’t reduce all environmental and health problems to one insidious thing, I believe there is a common denominator. That common denominator is glyphosate. My goal, by the end of this book, is to prove to you that I am right.

My argument, as you will see, is based on connecting the dots in the peer-reviewed science. Some of the scientific arguments that I present in this book are controversial, and some conventional scientific researchers won’t accept them. But this book brings together over 10 years of research that clearly shows how glyphosate is eroding both human and planetary health, resulting in a toxic legacy we are leaving future generations to contend with. This problem is too important to ignore. The goal of this book is to convince anyone who eats, anyone who has children, and anyone who cares about the health of humans and the planet that we need to look much more closely and much more carefully at the impact of glyphosate on and beyond the food supply. Both the scientific community and our regulatory establishments have failed us. It is time to shine light onto the shadows—to convince the world about glyphosate’s diabolical mechanism of toxicity and give ourselves the tools we need to understand how glyphosate harms us and what we can do to protect ourselves and our families.

In chapters 1 and 2, I reveal the history of glyphosate—what it really is, how and why it was developed, and how it “works” as an herbicide. In these chapters I explore the rapidly growing body of scientific research that shows glyphosate’s devastating impact on ecosystems and wildlife. In chapters 3 through 6, I move more specifically into exactly how glyphosate impacts the human body: how it damages the gut microbiome, how it substitutes for the amino acid glycine during protein synthesis, and how it disrupts the all-important and little understood roles of phosphate and sulfate. In chapters 7 through 10, I look at how this biochemistry plays out in specific conditions—liver disease, infertility, neurological disorders, and autoimmunity—that are caused in part by glyphosate’s unique mechanism of toxicity. The final chapter is a call to action to safely rid the world of glyphosate, and to return to sustainable, or, even better, renewable organic agricultural practices. This last chapter also contains the best advice I can offer for how to take control of your health.

In recent years, glyphosate has gotten considerably more attention because of lawsuits that have linked it to cancer. Anyone who has read the scientific literature, even the most conventional medical doctors, understands now that glyphosate is carcinogenic, priming the body to fall prey to cancer. Throughout the book I address evidence that glyphosate causes physical damage leading to cancer, but I have chosen not to devote a chapter specifically to cancer. Why? Because cancer is the end of the line. What I want you to understand is how exposure to glyphosate sets the stage—through severe metabolic disruption—to take a person to cancer’s door.

Our path forward is twofold. To state it bluntly, we need to ban glyphosate worldwide. Banning this toxic chemical is the only real way to protect what we hold dear. Until that happens, and in the absence of proper regulatory oversight, we need to protect our own health and the health of our children.

I wrote this book to blow the whistle on one of the most toxic chemicals of our time, to inspire you to understand the science behind how we are being slowly poisoned by glyphosate, and to spur you into action. We got into this mess because of the greed of chemical companies that put profits over people. We can get out of this mess by insisting that people and the planet matter more. The science will lead us where we need to go. I invite you to journey with me.