Thanks a lot, Grandma: Negative effects of Roundup chemical doesn’t surface for generations, WSU researcher says

Much of the food we eat today may impact our great-grandchildren, a prominent Washington State University researcher said. Bayer, the company that owns the chemical in question, is fighting that assertion.

Washington State University Biology Professor Michael Skinner studied the effects of glyphosate in rats. Commonly found in Roundup, Skinner will be the first to say direct exposure to the chemical has not been found to be harmful.

Skinner exposed pregnant rats to glyphosate. The mothers had no harmful side effects. The rats’ children were unharmed. The grandchildren? Also fine. But when the study reached the great-grandchildren, more than than 90% of the animals developed one or more diseases.

“The diseases ran from tumors to prostate disease to ovary disease and major birth defects,” Skinner said. “ … If that compound changes the epigenetics in the sperm or the egg of the individual exposed, then they pass that on to the next generation and it keeps going for generations to come.”

For 20 years, Skinner has worked in the field of epigenetics, a once controversial field now widely accepted that studies how outside influences can alter DNA. Skinner’s study was published in Scientific Reports on Tuesday.

Bill Reeves, a toxicologist with Bayer, which now owns Monsanto, said Skinner’s study wasn’t credible for several reasons. Reeves said the control group of rats was switched out toward the end of the study, and the method for delivering the chemical – injected in the rat’s abdomen – was not indicative of how humans would be exposed to the chemical in Roundup.

“Essentially what you’re doing is after the fact going, ‘Well I don’t like how this study turns out so I’m going to change my control animals to be a whole different group of controls,’ ” Reeves said. “You can’t make comparisons that way.”

Skinner said this administration of the chemical was a standard approach, and pointed out that his study was peer-reviewed and published in an accredited scientific journal. Additionally, he said the switching of the control group was above board, as the father rat of the control was found to have an extremely high proclivity to his descendants developing obesity, and the control group was swapped with rats who had the same conditions. This information is disclosed in his methods.

Reeves said Bayer had conducted a multigenerational study, and said the study was available on its website. Charla Lord, Bayer communications, pointed out a study conducted between 1978 and 1980. Bayer was unable to provide a toxicologist to explain the study further but did provide an Environmental Protection Agency review of Bayer studies, though it did not mention rat studies.

Skinner said the study Lord provided is flawed. The usage of CD rats is improper, he said. The specific type of CD rat was not available because Monsanto had redacted that information in its document.

“They used CD rats, which is a highly inbred rat,” Skinner said. “Inbred lines of rats and mice and other organisms are known not to respond to environmental toxicants, and so essentially this has been known since the 1960s that you have to use outbred lines of rats to actually get good toxicology.”

Another issue is the Bayer study only had the rats studied until weaning age, which would be similar to a human at age 18. Most diseases in humans develop later in life.

“They only looked at weaned animals,” Skinner said. “That would be 28 days post-birth. At those ages, we don’t see disease either. You have to allow the animal to grow up until one year of age, which is an adult animal, middle-aged for humans. That’s when disease starts to develop, between 6-12 months of age in the rat.”

Reeves also pointed out that the study continually exposed each generation to the chemical, something his study did not do. The point, he said, is not direct exposure, which he agrees does not have a negative effect.

“There’s no more glyphosate in the system in the f2 and f3,” Skinner said. “Glysophate is not even around, yet there’s major disease in those organ systems. It’s because we’ve induced an epigenetic shift in the germ line – the sperm or egg – that causes this. So the premise of their argument – they are so used to combating direct exposure things they don’t even understand that this is a generational effect.”

He also said the Bayer study was an internal, industry-produced document, not an article that was peer-reviewed and published in a scientific journal, as his was. Susceptibility is key in epigenetics, Skinner said. The environmental exposure does not promote the disease itself, only the susceptibility to the disease. Though organic produce won’t have the chemical, glyphosate is extremely difficult to avoid.

“It’s taken up by the food,” Skinner said. “So the corn and the soy itself take up the glyphosate into the plant, so when they generate the food product the food product actually has glyphosate. There’s no way that we can avoid glyphosate.”

Skinner expected the pushback on his study from Monsanto. He said the company has a history of attempts to discredit academics.

“You’re going to see a fight here,” Skinner said. “But I’m used to that. … They will tell you whatever they need to tell you to still market their product.”

Skinner said with his findings, he had a moral duty to inform the public, regardless of the costs. He also said any chemicals involved in our food supply should be tested for generational impacts, not just direct exposure, including whatever chemical supplants Roundup, should that happen.