The globally bestselling herbicide Roundup can cause heart problems, according to a study conducted by researchers from the University of Caen, France, and Sapienza University of Rome, and published in the journal Cardiovascular Toxicology in December 2014.
The findings may explain the cases of heart problems or even sudden death reported in people or animals exposed to high levels of Roundup.
According to the study authors, reported cases of acute Roundup poisoning have been increasing. These are a different phenomenon than the chronic poisoning and health problems reported by many people living in areas of heavy Roundup use.
Results Consistent With Human Poisoning Incidents
The researchers exposed rabbits and rats to levels of Roundup herbicide comparable to those that might lead to acute poisoning in humans. They then surgically extracted the hearts from the rats (killing the animals), keeping the hearts alive in a laboratory solution so their function could be examined.
The hearts of rats and rabbits exposed to Roundup exhibited reduced intracellular uptake of calcium and an increased rate of arrhythmia (irregular heartbeat). They also showed an increase in conduction blocks, and even a 30-minute washout was unable to restore proper excitability.
These decreases in heart function could lead to the QT prolongation, atrioventricular conduction blocks and arrhythmias reported by hospital records in human cases of acute Roundup poisoning, the researchers wrote. They could also explain anecdotal reports by hunters of rabbits abruptly dying after crossing fields sprayed with Roundup, or by pet owners of their dogs having fatal seizures after spending time on lawns sprayed with the chemical.
Notably, no cardiac effects were seen when the researchers ran the experiment with pure glyphosate, the active ingredient of Roundup. This suggests that some additive chemical is responsible for the cardiac effects — yet regulatory agencies require only the active ingredient to be tested for safety.
Birth Defects Also A Concern
Other studies have indicated that Roundup may also have long-term health effects, as may the active ingredient glyphosate. A major concern is birth defects.
In 2009, the Argentinean National Council for Scientific and Technical Research (CONICET), announced the results of a study ordered by the Argentinean Health Ministry following years of complaints from residents of areas with heavy Roundup spraying (particularly near fields of “Roundup ready” genetically modified soy). Residents and area doctors had complained of a jump in rates of cancer and birth defects following the adoption of genetically engineered soy and the corresponding jump in Roundup use.
The researchers found that glyphosate produces birth defects of the heart, brain and intestines, even at doses 1,500 times lower than those used on Argentinean soy crops. Other defects observed include head deformity and changes to the central nervous system.
Because levels used in real life are so much higher, the risk in real life “is much more serious” than that seen in the lab, lead researcher Andres Carrasco said.
“The observed deformations are consistent and systematic,” he said.
A 2014 study conducted by researchers from the University of Leipzig, Germany, and Sadat City University in Egypt, in collaboration with Danish pig farmer Ib Borup Pedersen, and published in the Journal of Environmental & Analytical Toxicology, cataloged birth deformities in the offspring of pigs fed feed contaminated with low concentrations of Roundup.
The rate of birth defects increased in direct proportion to the dose of glyphosate found in the feed. A concentration of 0.25 parts per million (ppm) caused deformities to jump to one in 1,432, while a concentration of between 0.87 ppm and 1.13 ppm produced an astonishing birth defect rate of one in 260.