With the question of the endocrine-disrupting potential of Roundup at real-world doses still unsolved and glyphosate classified as a probable carcinogen, it’s time to restrict or ban glyphosate herbicides, writes Dr Ramon Seidler, PhD
In February last year a group of international scientists published a consensus statement drawing attention to the risks posed by rising levels of exposure to glyphosate-based herbicides (GBHs), especially in the light of glyphosate’s classification by the World Health Organization’s cancer agency IARC as a probable carcinogen. The scientists noted endocrine (hormone) disrupting effects of glyphosate herbicides in test-tube experiments and called for more studies to clarify whether levels present in foods and the environment can cause such effects in living humans.
Endocrine disruptors (EDs) have harmful effects on experimental mammals that are widely used as human surrogates at concentrations as low as parts per billion (ppb) and below.
Later in the year, the New York Times reported that GM glyphosate-tolerant crops have significantly increased the use of glyphosate-based herbicides in the US. This news was closely followed by the publication of a report by Food Democracy Now and the Detox Project showing high levels of glyphosate residues in popular foods and drinks.
Given the increasing risk to people posed by EDs, you’d expect regulators to be eager to take action. But sadly the opposite is true. The European Commission has been so tardy in regulating them that the European Court of Justice has declared that it has “unlawfully refrained from laying down rules”.
This issue of GBH exposures has gained urgency from a new study in rats, which showed that Roundup caused fatty liver disease at the minute concentration of 0.1 ppb given in drinking water over a long-term period. The glyphosate daily intake level from this dose was 4 nanograms per kilogram of bodyweight per day, which is 75,000 times below EU and 437,500 times below US permitted levels. The concentration of glyphosate in the drinking water (50 parts per trillion) was 14,000 times less than the concentration allowed in US drinking water (700 ppb).
Tests have shown that most Americans have glyphosate in their urine at ppb levels, suggesting a daily intake of around 1000-fold above the level that caused fatty liver disease in the rats. However, further research needs to be done to establish the glyphosate levels present in various body tissues, especially within endocrine organs like the pancreas.
It’s not certain that the fatty liver disease reported in the Roundup-fed rats was caused by the mechanism of endocrine disruption. But given the extremely low dose of Roundup that caused the effect and the known association between EDCs in general and non-alcoholic fatty liver disease, endocrine disruption is one plausible mechanism. These observations call for urgent further research to be conducted to confirm Roundup/glyphosate-induced organ toxicity at real world levels of ingestion, and to provide insight into the mechanisms of toxicity, including ED effects.
Glyphosate herbicides and endocrine disruption
In 2009, the International Endocrine Society issued its first warning about the dangers associated with chemicals that interact with, take the place of, or inhibit or stimulate the action of natural human hormones (EDs). Today, based upon highly credible research published in peer-reviewed journals by scientists around the world, there is little doubt that GBHs are endocrine disruptors at the relatively high doses tested thus far. Their endocrine activity at low, realistic doses is still uncertain and requires further research.
According to the International Endocrine Society, there is strong mechanistic and epidemiological evidence that endocrine disruption plays a role in a wide range of maladies, including obesity, non-alcoholic fatty liver disease associated with diabetes, female and male reproduction abnormalities (abnormal sperm and reduced fertility), hormone-sensitive cancers in females, prostate cancer, thyroid diseases, and neurodevelopment diseases (IQ loss and hyperactive behaviour). ….