(Updated February 17, adding criticism of study)
A new scientific paper examining the potential health impacts of Roundup herbicides found links between exposure to the weed killing chemical glyphosate and an increase in a type of amino acid known to be a risk factor for cardiovascular disease.
The researchers made their determinations after exposing pregnant rats and their newborn pups to glyphosate and Roundup through drinking water. They said they looked specifically at the effects of glyphosate-based herbicides (GBH) on urinary metabolites and interactions with the gut microbiome in the animals.
The researchers said they found a significant increase of an amino acid called homocysteine in male rat pups exposed to glyphosate and Roundup.
“Our study provides initial evidence that exposures to commonly used GBH, at a currently acceptable human exposure dose, is capable of modifying urine metabolites in both rat adults and pups,” the researchers stated.
The paper, titled “Low-dose exposure of glyphosate-based herbicides disrupt the urine metabolome and its interaction with gut microbiota,” is authored by five researchers affiliated with the Icahn School of Medicine at Mount Sinai in New York and four from the Ramazzini Institute in Bologna, Italy. It was published in the journal Scientific Reports February 5.
The authors acknowledged many limitations with their study, including a small sample size, but said their work showed that “gestational and early-life low-dose exposure to glyphosate or Roundup significantly altered multiple urine metabolomic biomarkers, in both dams and offspring.”
The study is the first on urinary metabolomic changes induced by glyphosate-based herbicides at doses currently considered safe in humans, the researchers said.
The paper follows the publication last month of a study in the journal Environmental Health Perspectives that found glyphosate and a Roundup product can alter the composition of the gut microbiome in ways that may be linked to adverse health outcomes. Scientists from the Ramazzini Institute were also involved in that research.
Robin Mesnage, one of the authors of the paper published last month in Environmental Health Perspectives, took issue with the validity of the new paper. He said the data analysis showed the differences detected between the animals exposed to glyphosate and those not exposed – the control animals – could have been similarly detected with randomly generated data.
“Overall, the data analysis doesn’t support the conclusion that glyphosate disrupts the urine metabolome and the gut microbiota of the exposed animals,” said Mesnage. “This study will only further confuse a bit more the debate on the toxicity of glyphosate.”
Several recent studies on glyphosate and Roundup have found an array of concerns.
Bayer, which inherited Monsanto’s glyphosate-based herbicide brand and its glyphosate-tolerant genetically engineered seed portfolio when it bought the company in 2018, maintains that an abundance of scientific study over decades confirms that glyphosate does not cause cancer. The U.S. Environmental Protection Agency and many other international regulatory bodies also do not consider glyphosate products to be carcinogenic.
But the World Health Organization’s International Agency for Research on Cancer in 2015 said a review of scientific research found ample evidence that glyphosate is a probable human carcinogen.
Bayer has lost three out of three trials brought by people who blame their cancers on exposure to Monsanto’s herbicides, and Bayer last year said it would pay roughly $11 billion to settle more than 100,000 similar claims.