New weed killer studies raise concern for reproductive health

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As Bayer AG seeks to discount concerns that Monsanto’s glyphosate-based herbicides cause cancer, several new studies are raising questions about the chemical’s potential impact on reproductive health.

An assortment of animal studies released this summer indicate that glyphosate exposures impact reproductive organs and could threaten fertility, adding fresh evidence that the weed killing agent might be an endocrine disruptor. Endocrine disrupting chemicals may mimic or interfere with the body’s hormones and are linked with developmental and reproductive problems as well as brain and immune system dysfunction.

In a paper published last month in Molecular and Cellular Endocrinology, four researchers from Argentina said that studies contradict assurances by the U.S. Environmental Protection Agency (EPA) that glyphosate is safe.

The new research comes as Bayer is attempting to settle more than 100,000 claims brought in the United States by people who allege exposure to Monsanto’s Roundup and other glyphosate-based herbicide products caused them to develop non-Hodgkin lymphoma. The plaintiffs in the nationwide litigation also claim Monsanto has long sought to hide the risks of its herbicides.

Bayer inherited the Roundup litigation when it bought Monsanto in 2018, shortly before the first of three trial victories for plaintiffs.

The studies also come as consumer groups work to better understand how to reduce their exposure to glyphosate through diet. A study published Aug. 11 found that after switching to an organic diet for just a few days, people could cut the levels of glyphosate found in their urine by more than 70 percent. Notably, the researchers found that the children in the study had much higher levels of glyphosate in their urine than did the adults. Both adults and children saw large drops in the presence of the pesticide following the diet change.

Glyphosate, the active ingredient in Roundup, is the most widely used weed killer in the world. Monsanto introduced glyphosate-tolerant crops in the 1990s to encourage farmers to spray glyphosate directly over whole fields of crops, killing weeds but not the genetically altered crops. The widespread use of glyphosate, by farmers as well as homeowners, utilities and public entities, has drawn growing concern over the years because of its pervasiveness and fears about what it could be doing to human and environmental health. The chemical is now found commonly in food and water and in human urine.

According to the Argentinian scientists, some of the reported effects of glyphosate seen in the new animal studies are due to exposure to high doses; but there is new evidence showing that even low dose exposure could also alter the development of the female reproductive tract, with consequences on fertility. When animals are exposed to glyphosate before puberty, alterations are seen in the development and differentiation of ovarian follicles and the uterus, the scientists said. Additionally, exposure to herbicides made with glyphosate during gestation could alter the development of the offspring. It all adds up to show that glyphosate and glyphosate-based herbicides are endocrine disruptors, the researchers concluded.

Agricultural scientist Don Huber, professor emeritus from Purdue University, said the new research expands on knowledge about the potential scope of damage associated with glyphosate and glyphosate-based herbicides and provides a “better grasp of understanding the seriousness of the exposure that is ubiquitous in our culture now.”

Huber has warned for years that Monsanto’s Roundup might be contributing to fertility problems in livestock.

One noteworthy study published online in July in the journal Food and Chemical Toxicology,  determined that glyphosate or glyphosate-based herbicides disrupted “critical hormonal and uterine molecular targets” in exposed pregnant rats.

A different study recently published in the journal Toxicology and Applied Pharmacology by researchers from Iowa State University looked at glyphosate exposure in mice. The researchers concluded that chronic low-level exposure to glyphosate “alters the ovarian proteome” (a set of expressed proteins in a given type of cell or organism) and “may ultimately impact ovarian function. In a related paper from the same two Iowa State researchers and one additional author, published in Reproductive Toxicology, the researchers said they did not find endocrine disrupting effects in the mice exposed to glyphosate, however.  

Researchers from the University of Georgia reported in the journal Veterinary and Animal Science that consumption by livestock of grain laced with glyphosate residues appeared to carry potential harm for the animals, according to a review of studies on the topic. Based on the literature review, glyphosate-based herbicides appear to act as “reproductive toxicants, having a wide range of effects on both the male and female reproductive systems,” the researchers said.

Alarming results were also seen in sheep. A study published in the journal Environmental Pollution looked at the impacts of glyphosate exposure on the development of the uterus in female lambs. They found changes that they said might affect the female reproductive health of sheep and show glyphosate-based herbicides acting as an endocrine disruptor.

Also published in Environmental Pollution, scientists from Finland and Spain said in a new paper that they had performed the first long-term experiment of the effects of “sub-toxic” glyphosate exposure on poultry. They experimentally exposed female and male quails to glyphosate-based herbicides from the ages of 10 days to 52 weeks.

The researchers concluded that the glyphosate herbicides could “modulate key physiological pathways, antioxidant status, testosterone, and the microbiome” but they did not detect effects on reproduction. They said the effects of glyphosate may not always be visible with “traditional, especially short-term, toxicology testing, and such testing may not fully capture the risks…”

Glyphosate and Neonicotinoids

One of the newest studies looking at glyphosate impacts on health was published this month in the International Journal of Environmental Research and Public Health.  Researchers concluded that glyphosate as well as the insecticides thiacloprid and imidacloprid, were potential endocrine disruptors.

The insecticides are part of the neonicotinoid class of chemicals and are among the most heavily used insecticides in the world.

The researchers said that they monitored the effect of glyphosate and the two neonicotinoids on two critical targets of the endocrine system: Aromatase, the enzyme responsible for estrogen biosynthesis, and estrogen receptor alpha, the main protein promoting estrogen signaling.

Their results were mixed. The researchers said with respect to glyphosate, the weed killer inhibited aromatase activity but the inhibition was “partial and weak.” Importantly the researchers said glyphosate did not induce estrogenic activity. The results were “consistent” with the screening program conducted by U.S. Environmental Protection Agency, which concluded that “there is no convincing evidence of a potential interaction with the estrogen pathway for glyphosate,” they said.

The researchers did see estrogenic activity with imidacloprid and thiacloprid, but at concentrations higher than the pesticide levels measured in human biological samples. The researchers concluded that “low doses of these pesticides should not be considered harmless,” however, because these pesticides, together with other endocrine disrupting chemicals, “might cause an overall estrogenic effect.”

The varying findings come as many countries and localities around the world evaluate whether or not to limit or ban continued use of glyphosate herbicides.

A California appeals court ruled last month that there was “abundant” evidence that glyphosate, together with the other ingredients in Roundup products, caused cancer.

Moms Exposed to Monsanto Weed Killer Means Bad Outcomes for Babies

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Concerns about the world’s most widely used herbicide are taking a new twist as researchers unveil data that indicates pervasive use of Monsanto Co.’s weed killer could be linked to pregnancy problems.

Researchers looking at exposure to the herbicide known as glyphosate, the key ingredient in Monsanto’s Roundup branded herbicides, said they tested and tracked 69 expectant mothers and found that the presence of glyphosate levels in their bodily fluids correlated with unfavorable birth outcomes. The research is still in preliminary stages and the sample size is small, but the team is scheduled to present their findings on Thursday at a conference put on by the Children’s Environmental Health Network (CEHN) in Washington, D.C.

“This is a huge issue,” said Paul Winchester, medical director of the neonatal intensive care unit at the Franciscan St. Francis Health system and professor of clinical pediatrics at Riley Hospital for Children in Indianapolis, Indiana. He said this is the first U.S. study to demonstrate glyphosate is present in pregnant women. “Everyone should be concerned about this.”

Glyphosate is a popular agricultural pesticide, used widely in farming operations around the world. It’s commonly sprayed directly on many food crops and those used for livestock feed. But it has become the subject of hot debate over the last few years because of research that links the herbicide to types of cancer and other health ailments. Monsanto is being sued by hundreds of people who claim they or their loved ones developed non-Hodgkin lymphoma because of exposure to glyphosate-based Roundup. Monsanto, the EPA and other regulatory bodies, say evidence of carcinogenicity is lacking and the chemical is among the safest of all pesticides used in food production. But documents discovered in the course of the litigation indicate the company may have manipulated scientific research to hide evidence of harm.

The team that presented their report Wednesday included scientists who have long been skeptical of Monsanto’s products as well as medical researchers who have come to have concerns about glyphosate and other pesticides through their study of pediatric health problems.

Winchester, who led the urine sampling study, said his look at glyphosate and pregnant women is in very early stages and he and co-researchers are hoping to launch a much larger project later this year. The preliminary work detected glyphosate in the urine of 63 of 69 (91%) pregnant women receiving prenatal care through an Indiana obstetric practice. Researchers collected the data over two years, from 2015-2016, and found that higher glyphosate levels in women correlated with significantly shorter pregnancies and with lower adjusted birth weights.

Correlation does not prove causation. Still, the findings are worrisome because low birth weights and shortened gestation are seen as risk factors for many health and/or neurodevelopmental problems over the course of an individual’s life. Low birth-weight babies are more likely to have diabetes, heart disease, high blood pressure, and to be obese, research shows.

People can be exposed to glyphosate through food and through association with farming operations that spray glyphosate on corn and soybean production fields. Both soy and corn, along with several other crops, have been genetically engineered to tolerate direct application of glyphosate. Farmers often also use glyphosate directly on wheat, oats and other non-genetically engineered crops shortly before harvest, leading to residues in grain-based food products.

Glyphosate use has climbed sharply over the last two decades with the rise of genetically engineered crops and in connection with the subsequent spread of glyphosate-resistant weeds. Dr. Charles Benbrook, one of the scheduled presenters at the CEHN conference, projects that by 2020, “more acres of cropland in the Midwest will harbor three or more glyphosate-resistant weeds than one or none.” Farmers have been trying to fight the resistant weeds with more glyphosate and other chemicals. New crops engineered to tolerate 2,4-D and dicamba herbicides mixed with glyphosate are being rolled out now. Industry data indicates herbicide use is expected to continue to climb, making it ever more critical for scientists and medical professional to get a handle on exposure levels and impacts on reproductive health, the team said in their presentation.

Winchester has been conducting research into pesticide exposures and impacts on pregnant women for many years, including in-depth work on atrazine, another herbicide popular with farmers. He said he was surprised to see such a high percentage of women tested showing glyphosate in their urine. He said much more research on glyphosate impacts is needed, and more data is needed on levels of exposure through food. He was sharply critical of the U.S. government, which routinely skips testing for glyphosate residues in food even though regulatory agencies test thousands of food products each year for residues of other types of pesticides, including atrazine.

He and the other researchers are calling on the Centers for Disease Control to include glyphosate and its primary metabolite, aminomethylphosphonic acid (AMPA) in biomonitoring work it does to track levels of pesticides and other chemicals in urine and blood.

“Is this level of exposure safe or not? We’ve been told it is, but exposures haven’t been measured,” Winchester said. “It’s mind-boggling.”

(First posted in The Huffington Post)