Herbicide spraying on a field
Herbicide being sprayed on a field in North Dakota. Photo via Wikimedia Commons

German chemical company Bayer on Thursday disputed a UC San Diego study that linked its weed killer Roundup to a rise in liver disease among humans.

The study, published by UCSD researchers Tuesday in the journal Clinical Gastroenterology and Hepatology, examined the content of glyphosate in the urine samples of two groups of people: one with a diagnosis of nonalcoholic fatty liver disease and one without.

The study found a higher glyphosate content in the urine of subjects with liver disease, with researchers contending they controlled the results for possible underlying factors like age, body mass index, race or diabetes diagnosis.

Bayer representatives countered that claim and argued the study’s results are hollow because of it.

“While we are still examining this recently released study, the data indicates that the researchers failed to consider confounding factors including potential existing metabolic disorders in participants,” the company said in a statement.

Bayer’s subsidiary, Monsanto, manufactures Roundup, which has increased in use significantly since the mid-1990s. According to UCSD’s researchers, nonalcoholic fatty liver disease in the U.S. has also increased over that same period of time. Glyphosate is the most widely used herbicide in the country, according to UCSD.

Monsanto has faced scrutiny for Roundup’s possible negative health effects, losing three lawsuits in California since last summer, including one in Alameda County on Monday, to people who claim glyphosate gave them cancer.

Bayer has steadfastly pushed back on those claims, citing an announcement earlier this month from the U.S. Environmental Protection Agency saying glyphosate poses no public health risks when used correctly and is not a carcinogen. The company also said its product does not lead to liver disease or damage.

“All pesticides, including glyphosate, are tested for their potential to harm liver function in tests that rely on internationally accepted protocols and are conducted according to good laboratory practices,” the company said. “All of this testing demonstrates that glyphosate does not harm liver function.”

— City News Service

Chris Jennewein

Chris Jennewein is Editor & Publisher of Times of San Diego.