Skip to content

Studies finding health effects from BPA keep appearing. BPA (bisphenol-A) is a chemical used in many everyday products (e.g. the lining of soda and food cans, store receipts) and so almost all humans are exposed to it daily. Researchers are getting increasingly worried about BPA and related chemicals (including substitutes for BPA such as BPS) because they are endocrine (hormone) disruptors with health effects in humans and animals. This chemical is so widely used that more than 7 billion metric tons of it are produced annually throughout the world.

Unfortunately the US government keeps agreeing with the chemical industry that the chemical is "safe", and disregarding the results of studies finding health effects (reproductive effects, obesity, etc). Of course the chemical industry is fighting tooth and nail to discredit studies done by independent researchers - a lot of money is at stake.

The following are excerpts from an article describing the latest study finding health effects from low dose exposure from BPA - it altered the amount of insulin released by the person (and so perhaps influencing the development of type 2 diabetes). What was worrisome is that the dose is considered "safe" by the US government - and in the study people were exposed to it once, while in real life humans are exposed to such doses multiple times daily.

The good news is that BPA is excreted within a day, but the bad news is that we the keep being exposed to it. By the way, substitutes for BPA (such as BPS) are just as bad, and are also endocrine disruptors - after all, they're all related chemically. So buying BPA-free canned food or plastic won't help a person avoid endocrine disruptors - these also leach into food. From an article written by Lynn Peeples at Environmental Health News:

In a scientific first, researchers gave people BPA — and saw a link to precursor of type 2 diabetes

In a scientific first, researchers gave people BPA — and saw a link to precursor of type 2 diabetesThe controversial study suggests that BPA exposure deemed safe by the feds could alter the amount of insulin released and elevate people's type 2 diabetes risk. 

A first-of-its-kind study of a small group of people exposed to a very small amount of bisphenol-A (BPA) is raising questions about the federal government's stance that low doses of the common chemical are safe — as well as the ethics of conducting such an experiment on humans.

...continue reading "Exposure to BPA Has An Effect on Insulin Levels"

Endocrine disruptors are in the news frequently nowadays. These are chemicals that interfere with the body's endocrine (or hormone) systems and can produce all sorts of negative health effects, including all sorts of reproductive problems in both males and females. Phthalates and parabens (both used in common everyday products) are examples of endocrine disruptors.

The latest is that a study conducted in Pakistan found that women with endometriosis had high levels of a common endocrine disruptor - a phthalate known as diethylhexyl phthalate (DEHP), which is used in many everyday products. Healthy women without endometriosis did not have detectable levels of DEHP in their serum (blood) in this study. The researchers say that these results suggest that the phthalate DEHP, which is used in plastics, has a contributing role in the development of endometriosis.

Endometriosis is an often painful condition in which tissue that normally lines the inside of the uterus (the endometrium) grows outside the uterus. Symptoms may include abdominal pain, heavy periods, and infertility.

Phthalates are used as plasticizers -  substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used in many consumer products, including in household furnishings, soft vinyl toys, flooring,medical equipment, air fresheners, cosmetics, perfumes, food packaging, medicine, and insecticides. Some ways humans are exposed to DEHP is from eating processed food (which contains some DEHP that has leached from food processing machines and packaging materials) and from applying personal care and cosmetic products to the skin.

Other studies have also found that DEHP levels are significantly higher in women with endometriosis compared to women without endometriosis. Interestingly, in this study - those with more advanced stages of endometriosis also tended to have the highest levels of DEHP. Excerpts from the study by  Sadia Nazir et al from the Journal of Human Reproductive Sciences:

Women Diagnosed with Endometriosis Show High Serum Levels of Diethyl Hexyl Phthalate

Abstract: Endometriosis is one of the common causes of infertility with very diverse etiology. In modern lifestyle, humans are exposed to several endocrine-disrupting chemicals (EDCs) which may lead to reproductive disturbances. Diethyl hexyl phthalate (DEHP) is one of the common EDCs to which women are exposed by the use of cosmetics, perfumes, food packaging, medicine, and insecticides.

...continue reading "Common Chemicals and Endometriosis"

The following article in a popular magazine follows up on research that came out last year about the alarming steep decline in male sperm counts and sperm concentration over the past few decades. This is true for the U.S., Europe, Australia, New Zealand, and it is thought world wide. The article discusses the causes: environmental chemicals and plastics, especially those that are endocrine disruptors (they disrupt a person's hormones!). These chemicals are all around us, and we all have some in our bodies (but the amounts and types vary from person to person). Some examples of such chemicals are parabens, phthalates, BPA and BPA substitutes.

Even though there are effects from these chemicals throughout life, some of the worst effects from these chemicals seem to be during pregnancy - with a big effect on the developing male fetus. Testosterone levels in men are also droppingBottom line: males are becoming "less male", especially due to their exposure to all these chemicals when they are developing before birth (fetal exposure). Since it is getting worse with every generation of males, the concern is that soon males may be unable to father children because their sperm count will be too low - infertility.

Why isn't there more concern over this? What can we do? We all use and need plastic products, but we need to use safer chemicals in products, ones that won't mimic hormones and have endocrine disrupting effects. Remember, these chemicals have more effects on humans than just sperm quality (here and here). While you can't totally avoid plastics and endocrine disrupting chemicals, you can definitely lower your exposure. And it's most important before conception (levels of these chemicals in both parents), during pregnancy, and during childhood.

Do go read the whole article. Excerpts from Daniel Noah Halpern's article in GQ: Sperm Count Zero

A strange thing has happened to men over the past few decades: We’ve become increasingly infertile, so much so that within a generation we may lose the ability to reproduce entirely. What’s causing this mysterious drop in sperm counts—and is there any way to reverse it before it’s too late? 

Last summer a group of researchers from Hebrew University and Mount Sinai medical school published a study showing that sperm counts in the U.S., Europe, Australia, and New Zealand have fallen by more than 50 percent over the past four decades. (They judged data from the rest of the world to be insufficient to draw conclusions from, but there are studies suggesting that the trend could be worldwide.) That is to say: We are producing half the sperm our grandfathers did. We are half as fertile.

The Hebrew University/Mount Sinai paper was a meta-analysis by a team of epidemiologists, clinicians, and researchers that culled data from 185 studies, which examined semen from almost 43,000 men. It showed that the human race is apparently on a trend line toward becoming unable to reproduce itself. Sperm counts went from 99 million sperm per milliliter of semen in 1973 to 47 million per milliliter in 2011, and the decline has been accelerating. Would 40 more years—or fewer—bring us all the way to zero? 

I called Shanna H. Swan, a reproductive epidemiologist at Mount Sinai and one of the lead authors of the study, to ask if there was any good news hiding behind those brutal numbers. Were we really at risk of extinction? She failed to comfort me. “The What Does It Mean question means extrapolating beyond your data,” Swan said, “which is always a tricky thing. But you can ask, ‘What does it take? When is a species in danger? When is a species threatened?’ And we are definitely on that path.” That path, in its darkest reaches, leads to no more naturally conceived babies and potentially to no babies at all—and the final generation of Homo sapiens will roam the earth knowing they will be the last of their kind.

...continue reading "Will All Men Eventually Be Infertile?"

The reality is that we are exposed to thousands of industrial chemicals in our daily lives - in our foods, products, even in dust. Chemicals can get into us through ingestion (food and contaminated water), through inhalation (in dust and contaminated air), and can even be absorbed through the skin. Blood and urine tests can measure the chemicals that we have been exposed to - this is called biomonitoring. Of course, each of us has different levels of these unwanted chemicals - but yes, even those living off the grid and eating all organic foods will have some unwanted chemicals in their bodies. Studies are finding that these chemicals have negative health effects - some effects we know about, but many, many are still unknown.

Of big concern is a pregnant woman's exposure to chemicals because they can have health effects on the developing baby, including life-long effects (e.g. neurological effects, endocrine disrupting effects, immunological effects). Yes, this is scary stuff, especially because we know so little about their effects.

A group of University of California researchers figured out a new way to measure these chemicals in the blood (it's called liquid chromatography-quadrupole time-of-flight mass spectrometry), and looked for the presence of 696 chemicals in a group of 75 pregnant women in California. They found an average of 56 chemicals in each woman (the number of chemicals ranged from 32 to 73 chemicals per woman), and also found a number of chemicals never monitored before. Yikes.

What to do? We can't totally avoid unwanted chemical exposure, but we can lower our exposure to some chemicals. Look at the last post for ideas on how to minimize exposures in our foods. Try to avoid pesticides - both in your home, yard, and in food (eat organic food as much as possible). Avoid fragrances and products containing fragrances. Avoid dryer sheets, air fresheners, and scented candles. Read labels and avoid products with fragrances, parabens, stain protectors, flame retardants, and antibacterials , anti-odor, or anti-mildew products.  Avoid non-stick or Teflon cookware. Avoid BPA and also the replacement chemicals (yes, they're as bad). Don't microwave plastic containers (glass dishes are OK). Glass & stainless steel for foods is fine. Wash hands before eating. Yes, it's a lifestyle change, but one worth doing.

From Medical Xpress: Study finds 56 suspect chemicals in average pregnant woman

Each year, tens of thousands of chemicals are manufactured in or imported into the United States—more than 30,000 pounds of industrial chemicals for every American—yet experts know very little about which chemicals may enter people's bodies, or how these substances affect human health. Now, scientists at UC San Francisco have found a way to screen people's blood for hundreds of chemicals at once, a method that will improve our ability to better assess chemical exposures in pregnant women, and to identify those exposures that may pose a health risk. 

...continue reading "Study Finds An Average of 56 Suspect Chemicals In Pregnant Women"

The American Academy of Pediatrics (representing 67,000 pediatricians) has come out with a statement expressing serious health concerns about the Food and Drug Administration's  (FDA) lax regulation of chemicals added to food and food packaging - such as additives, BPA, colors, flavors, nitrates, nitrites, etc. They also list ways that this problem could be fixed (Congress needs to pass legislation!), and also give some steps on how people can lower their exposure to these chemicals.

A panel of experts representing the group issued both a technical report and a statement which talked about the scientific evidence (which grows yearly) against such compounds such as bisphenol A (BPA), phthalates, perfluoroalkyl chemicals (PFCs) used in grease-proof paper, certain colors (dyes), and preservatives. These chemicals can enter into the body and cause harm or health problems, for example  by disrupting crucial biological processes such as the endocrine (hormone) system and immune system. A number of these chemicals are thought to mimic or suppress natural hormones - they are endocrine disruptors. Children and developing fetuses are especially vulnerable to long-term effects. They also expressed concern with nonpersistent pesticides.

Many of the chemicals currently in the food supply "have not been tested at all, while others have not been tested for endocrine disruption or their impact on brain development, and their effect on children's health is still unknown," said Trasande, the paper's lead author and an associate professor of pediatrics at New York University School of Medicine in New York. This is because the old required tests are too simplistic, too crude, using old out-dated technology and knowledge.

The American Academy of pediatrics points out in the statement that currently: "more than 10 000 chemicals are allowed to be added to food and food contact materials in the United States, either directly or indirectly, under the 1958 Food Additives Amendment to the 1938 Federal Food, Drug, and Cosmetic Act (FFDCA)". Many of these were grandfathered in for use by the federal government before the 1958 amendment, and an estimated 1000 chemicals are used under a “generally recognized as safe” (GRAS) designation process..."  Whew.... so many chemicals...

Is there a problem with GRAS? Of the approximate 1,000 GRAS compounds added to food and food packaging, the large majority were designated as such by either the company that manufactures them or a paid consultant. (Do you see a problem here? The conflicts of interest are huge - the fox is guarding the chickens.)

How can you personally lower your exposure to all these chemicals? 1) Eat as many fresh fruits and vegetables as possible, and avoid eating canned foods (the can lining has BPA or other just as worrisome chemicals - bisphenols), 2) Avoid processed meat, especially during pregnancy (nitrates, nitrites, etc), 3) Avoid microwaving food or liquids in plastic containers (chemicals leach out) - including infant formula and breastmilk, 4) Avoid putting plastics in the dishwasher (chemicals leach out), 5) Use alternatives to plastic such as glass and stainless steel, 6) Avoid plastics with recycling codes 3 (phthalates), 6 (styrene), and 7 (bisphenols) unless plastics are labeled as “biobased” or “greenware,” indicating that they are made from corn and do not contain bisphenols, 7) Wash  hands before eating, and wash fruits and vegetables that cannot be peeled. 8) Also - read the ingredients on all labels, and look for "real" ingredients ...continue reading "Pediatricians Have Health Concerns About All the Additives In Food"

The researchers of a recent study caution about the regular use of lavender and tea tree essential oils (e.g. in lotions or soaps) - that the oils may act as endocrine disruptors (chemicals that disrupt hormones and their actions in the body). Earlier research found a link between regular use of lavender essential oil and tea tree oil and abnormal breast growth in boys - called prepubertal gynecomastia. The condition went away after they stopped using the products.

Now researchers examined 8 common chemical components of lavender and tea tree oils for endocrine disrupting activity in lab tests - and yes, they found varying degrees of endocrine-disrupting activity in the chemicals. The researchers (from the National Institute of Environmental Health Sciences or NIEHS) warn that endocrine disrupting chemicals found in these 2 essential oils are also found in 65 other essential oils.

Note that essential oils are widely available, but they are not regulated by the FDA. Bottom line: No matter the age, avoid prolonged use of lavender and tea tree oil in personal care products, including "aromatherapy" -  especially important for children and pregnant women. The results were presented today at the 100th annual meeting of the Endocrine Society (ENDO) in Chicago. From Science Daily:

Chemicals in lavender and tea tree oil appear to be hormone disruptors

A new study lends further evidence to a suspected link between abnormal breast growth in young boys -- called prepubertal gynecomastia -- and regular exposure to lavender or tea tree oil, by finding that key chemicals in these common plant-derived oils act as endocrine-disrupting chemicalsLavender and tea tree oil are among the so-called essential oils that have become popular in the United States as alternatives for medical treatment, personal hygiene and cleaning products, and aromatherapy. Various consumer products contain lavender and tea tree oil, including some soaps, lotions, shampoos, hair-styling products, cologne and laundry detergents.   ...continue reading "Are Some Essential Oils Endocrine Disruptors?"

...continue reading "Can We Avoid the Endocrine Disruptors Around Us?"

A recent study by a team of researchers from France and Denmark highlighted the point that all medicines have side-effects, even though we may not realize it for years. Ibuprofen is a great non-prescription pain reliever - a nonsteroidal anti-inflammatory drug (NSAID), but it should be taken only when needed. Ibuprofen is found in such commonly used medicines as Advil and Motrin. The researchers found that ibuprofen has antiandrogenic effects (alters or disrupts the endocrine system) which results in a temporary condition called "compensated hypogonadism" when taken for extended periods by healthy young men (in the study 600 mg was taken daily for 6 weeks).

The researchers stress that this "depression of important aspects of testicular function, including testosterone production" was temporary from short term use, but they were concerned with those who take it daily for longer periods, such as athletes. They wondered whether this could be contributing to lowered sperm levels and the drops in male fertility that we are seeing in western developed countries. [Note that ibuprofen use has also been linked to a higher risk of cardiac arrest.] From Medical Xpress:

Taking ibuprofen for long periods found to alter human testicular physiology

A team of researchers from Denmark and France has found that taking regular doses of the pain reliever ibuprofen over a long period of time can lead to a disorder in men called compensated hypogonadism. In their paper published in Proceedings of the National Academy of Sciences, the group describes their study, which involved giving the drug to volunteers and monitoring their hormones and sperm production.

To learn more about the possible impacts of the popular anti-inflammation drug Ibuprofen on male fertility when taken for long periods of time, the researchers asked 31 men between the ages of 18 and 35 to take 600 milligrams (three tablets) a day of the drug for six weeks. Other volunteers were given a placebo. Over the course of the study, the volunteers were tested to see what impact the drug had on their bodies.

The researchers report that just two weeks into the study, they found that all of the volunteers had an increase in luteinizing hormones, which the male body uses to regulate the production of testosterone. The increase indicated that the drug was causing problems in certain cells in the testicles, preventing them from producing testosterone, which is, of course, needed to produce sperm cells. They further report that the change caused the pituitary gland to respond by producing more of another hormone, which forced the body to produce more testosterone. The net result was that overall testosterone levels remained constant, but the body was overstressing to compensate for the detrimental impact of the Ibuprofen—a state called compensated hypogonadism.

The researchers note that while compensated hypogonadism can cause a temporary reduction in the production of sperm cells, reducing fertility, it is generally not cause for alarm. What is more of a concern, they note, is using the drug for longer periods of time. It has not been proven yet, but the researchers suspect such use, as is seen with some professional athletes or others with chronic pain issues, might lead to a condition called overt primary hypogonadism, in which the symptoms become worse—sufferers report a reduction in libido, muscle mass and changes in mood. Additional studies are required, they note, to find out if this is, indeed, the case. [Original study.]

The prestigious medical journal The Lancet recently released a report by its Commission On Pollution and Health on the effects of various types of pollution (water, air, occupational, chemical, etc) on people and world economies - that is, the effect of pollution on "global health". The main finding: Diseases caused by pollution were responsible in 2015 for an estimated 9 million premature deaths -- 16 percent of all deaths worldwide. Pollution is now known to cause a wide variety of diseases and health problems, including asthma, cancer, neurodevelopmental disorders, and birth defects in children; and heart disease, stroke, chronic obstructive pulmonary disease, and cancer in adults. The list of health effects keeps increasing. [See all posts on pollution.]

The report states that certain types of pollution are increasing throughout the world - air, chemical, and soil pollution.They also discuss new and emerging pollutants (most of them chemical pollutants) whose effects on human health
are not yet fully understood, yet they are widely found in the environment and detected in most humans. The authors of the report even say: "At least some of these chemical pollutants appear to have potential to cause global epidemics of disease, disability, and death."

Chemical pollutants include: developmental neurotoxicants (e.g. pesticides, lead, mercury), endocrine disruptors (which have reproductive effects and can alter fertility), new classes of pesticides such as the neonicotinoids, chemical herbicides such as glyphosate (found in Roundup and the most commonly used pesticide in the world), nano-particles, and pharmaceutical wastes.

While most deaths from all sorts of pollution are currently occurring in poorer developing countries (e.g. China and India), we in the United States also have health effects and deaths from pollution - just not on the scale of those countries. Also, remember that winds carry pollutants globally - so that air pollution in China will cross the Pacific Ocean on the winds to the US.

Everyone agrees that taking action works - think of the success in banning lead, asbestos, and DDT in the United States. And amounts of six common air pollutants have been reduced by about 70% since passage of the Clean Air Act in 1970. We can thank laws, and organizations established due to environmental problems and crises in the past (e.g. the Environmental Protection Agency (EPA), Superfund legislation, Clean Water Act, Clean Air Act) for that.

From Science Daily: Pollution responsible for 16 percent of early deaths globally

Diseases caused by pollution were responsible in 2015 for an estimated 9 million premature deaths -- 16 percent of all deaths worldwide, according to a report. Simon Fraser University health sciences professor Bruce Lanphear is a Commissioner and author of The Lancet Commission on Pollution and Health that has released a report detailing the adverse effects of pollution on global health. ...."Pollution, which is at the root of many diseases and disorders that plague humankind, is entirely preventable." 

Commission findings include: - Pollution causes 16% of all deaths globally. Diseases caused by pollution were responsible in 2015 for an estimated 9 million premature deaths -- 16% of all deaths worldwide -- three times more deaths than AIDS, tuberculosis, and malaria combined; and fifteen times more than all wars and other forms of violence. It kills more people than smoking, hunger and natural disasters. In some countries, it accounts for one in four deaths. - Pollution disproportionately kills the poor and the vulnerable. Nearly 92% of pollution-related deaths occur in low- and middle-income countries. Within countries, pollution's toll is greatest in poor and marginalized communities. Children face the highest risks because small exposures to chemicals in utero and in early childhood can result in lifelong disease and, disability, premature death, as well as reduced learning and earning potential. - Pollution is closely tied to climate change and biodiversity. Fossil fuel combustion in higher-income countries and the burning of biomass in lower-income countries accounts for 85% of airborne particulate pollution. Major emitters of carbon dioxide are coal-fired power plants, chemical producers, mining operations, and vehicles.

A few excerpts (lead & pesticides) from the report in The Lancet: The Lancet Commission on pollution and health

Another example of the economic benefits of addressing pollution is seen in the consequences of removing lead from gasoline in the USA. This intervention began in 1975 and, within a decade, had reduced the mean blood concentration of lead in the population by more than 90%, almost eliminated childhood lead poisoning, and increased the cognitive capacity of all American children born since 1980 by 2–5 IQ points. This gain in intelligence has increased national economic productivity and will yield an economic benefit of US$200 billion (range $110 billion–300 billion) over the lifetimes of each annual cohort of children born since 1980, an aggregate benefit to-date of over $6 trillion.

Developmental neurotoxicants: Evidence is strong that widely used chemicals and pesticides have been responsible for injury to the brains of millions of children and have resulted in a global pandemic of neurodevelopmental toxicity. The manifestations of exposure to these chemicals during early development include loss of cognition, shortening of attention span, impairment of executive function, behavioural disorders, increased prevalence of attention deficit and hyperactivity disorder, learning disabilities, dyslexia, and autism.

Pesticides: More than 20,000 commercial pesticide products, including insecticides, herbicides, fungicides, and rodenticides are available on world markets. More than 1.1 billion pounds of these products are used in the USA each year and an estimated 5.2 billion pounds globally. ....The organophosphate insecticides are a large and widely used class of pesticides. Members of this class of chemicals are powerful developmental neurotoxicantsand prenatal exposures are associated with persistent deleterious effects on children’s cognitive and behavioural function and with long-term, potentially irreversible, changes to brain structure that are evident on MRI. 

Chemical herbicides account for nearly 40% of global pesticide use and applications are increasing. A major use is in production of genetically modified food crops engineered to be resistant to glyphosate (Roundup), the world’s most widely used herbicide. Glyphosate-resistant, so-called “Roundup Ready” crops, now account for more than 90% of all corn and soybeans planted in the USA, and their use is growing globally. Glyphosate is widely detected in air and water in agricultural areas, and glyphosate residues are detected in commonly consumed foods.

Once again the controversial herbicide (weed killer) glyphosate is in the news. Glyphosate is the active ingredient in Roundup (manufactured by Monsanto), and is the most commonly used pesticide in the world. Its use is increasing annually since the introduction of genetically modified crops that are tolerant of glyphosate being sprayed on them (Roundup Ready crops), and since the use of "preharvest" applications of Roundup. Over the years the US government has generally NOT been tracking how much glyphosate residues are in the foods we eat, but whenever a food is studied for glyphosate residues - they are found. (see all posts) Which means people are constantly ingesting low levels of glyphosate residues.

But what does that mean for humans? A  recently published study of 100 adults over the age of 50, residing in Southern California, and followed from 1993 to 2016, looked at detectable glyphosate and its metabolite aminomethylphosphonic acid (AMPA) residues in urine. They found that the number of people with detectable residues in urine, and also the actual levels found in the urine, really, really increased in the 23 years. The percentage of people who tested positive for glyphosate shot up by 500% in that time period - from 12 percent of the samples to 70 percent. WOW!

Are there health effects from constant ingestion in food from low levels of glyphosate? We don't know, because the studies on humans have not been done. There are a number of health concerns, including that it is a carcinogen (it has been classified as a "probable carcinogen" by some agencies), liver and kidney damage, that it acts as an antibiotic and disrupts the gut microbiome, and endocrine disruption. The researchers of this study are especially concerned about possible glyphosate health effects on the liver (liver disease), based on animal studies (animals exposed chronically to very low levels), and want to research this further.

However, the EPA keeps insisting it's safe (and to please ignore the conflicts and deals done with Monsanto in recent years), and actually raised the levels allowed in 2013 (due to corporate lobbying). Also, glyphosate is still not monitored by the Department of Agriculture's pesticide data program or the CDC's (Centers for Disease Control and Prevention) monitoring program of human exposure to environmental chemicals.

What can you do? Try to eat as many organic foods as possible because glyphosate (and Roundup) are not allowed to be used in organic farming. And don't use Roundup on your own property - because you can be exposed to it numerous ways (drinking and eating it in food, inhalation, through the skin).

From Medical Xpress: US study finds rise in human glyphosate levels

Levels of glyphosate, a controversial chemical found in herbicides, markedly increased in the bodies of a sample population over two decades, a study published Tuesday in a US medical journal said. The increase dated from the introduction of genetically-modified glyphosate-tolerant crops in the United States in 1994.

Researchers compared the levels of glyphosate in the urine of 100 people living in California. It covered a 23-year period starting from 1993, the year before the introduction of genetically-modified crops tolerant to Roundup. Glyphosate-containing Roundup, produced by US agro giant Monsanto, is one of the world's most widely-used weedkillers.

"Prior to the introduction of genetically modified foods, very few people had detectable levels of glyphosate," said Paul Mills, of the University of California at San Diego School of Medicine, the study's principal author. Among the study group, detectable amounts increased from an average of 0.20 micrograms per liter in 1993-1996 to an average of 0.45 micrograms in 2014-2016.

In July, California listed glyphosate as carcinogenic, and the World Health Organization International Agency for Research on Cancer called it "probably carcinogenic" in 2015. There are few human studies on the effects of glyphosate, but research on animals demonstrated that chronic exposure can have adverse effects, said Mills. Along with the European Commission's proposal on Tuesday, the European Parliament approved a non-binding resolution calling for the chemical to be banned by 2022.

Excerpts from Consumer Reports: We May Be Consuming More Glyphosate Than Ever Before

A 2016 report in the journal Environmental Health that looked at human and animal studies found a link between glyphosate exposure and a number of health problems, including liver and kidney damage, endocrine disruption, and an elevated risk of non-Hodgkin’s lymphoma. But a vast majority of those studies were done with animals.

In fact, very few human studies have been done on the health effects of glyphosate, and no federal agency monitors how much of the chemical makes it from the environment into our bodies. That lack of information makes it difficult to even begin to assess how much glyphosate is potentially harmful to humans and whether current exposure levels are above or below that mark.