It's no secret that the weed killer glyphosate shows up in our food. But how much of a health risk is this to consumers? A new review paper examining the evidence offers a reassuring conclusion.
If you search for “glyphosate in food,” you'll run headfirst into an endless list of copycat stories, all warning about the dangers of weedkiller-tainted cereal, bread, crackers, baby food, chips, eggs, meat— and basically any other food you can think of. The template is as follows: glyphosate is everywhere; it causes everything from cancer to kidney disease; you should buy Non-GMO Project-verified products to avoid the herbicide.
Here was the first result from my search: Glyphosate in Food: Complete List of Products and Brands Filled With Dangerous Weed-Killer.
We've previously examined the “glyphosate causes [insert nasty disease here]” claims, as well as the nebulous benefits of buying anything marketed with a non-GMO sticker of any kind. Today I want to focus on a new review examining the claim that dangerous amounts of glyphosate show up in popular foods.
A team of scientists evaluated the research that has been done to date on the risk posed by glyphosate exposure through food. Writing in Comprehensive Reviews in Food Science and Food Safety, they reached a conclusion that may surprise the average LiveLoveFruit reader:
Conclusions of risk assessments, based on dietary modeling or urine data, are that exposures to glyphosate from food are well below the amount that can be ingested daily over a lifetime with a reasonable certainty of no harm.
All the authors are employees at Bayer, a major manufacturer of glyphosate-based weedkillers. Keeping in mind that the company has an incentive to defend its product, let's examine the article's findings, paying attention to whether or not they depart from the conclusions of other similarly extensive literature reviews.
Measuring pesticides in food
First, how do scientists measure pesticide residues in food, and how do they determine if consumers face a health risk from these exposures? Every pesticide employed by US farmers undergoes a rigorous review before it's approved by the Environmental Protection Agency (EPA). There are two key aspects to that process as it relates to food safety.
Using data from animal toxicology studies, The EPA determines the maximum exposure at which a chemical doesn't have a negative health impact, the no observed adverse effect level, or NOAEL. The agency then divides that number by a safety factor of 100 to 1,000 to reach a very conservative reference dose (rfD). The EPA then sets a tolerance for each pesticide it approves, which, the agency explains, “is the maximum permissible level for pesticide residues allowed in or on human food and animal feed.”
The tolerance is used to ensure that pesticide users follow application directions. The US Department of Agriculture (USDA) and Food and Drug Administration (FDA) periodically test food samples to ensure that residue levels fall below the tolerance. The two agencies can confiscate food items that violate this standard.
Regulatory agencies worldwide follow some version of this extensive review process, and their results are often later validated in studies conducted by independent research groups. The new paper summed up the results this way:
Regulatory surveys are an important tool to ensure postmarketing phytosantitary vigilance and play an important role in regulatory risk assessment … The ongoing surveys of glyphosate residues beginning with samples collected in 2010 (EFSA, 2013) and most recently with samples from 2018 (EFSA, 2020) suggest a high degree of compliance and provide no indication that residues have exceeded regulatory levels. Residue studies by nonregulatory agency investigators are helpful additional data beyond findings of regulatory agencies
Activist outfits, most notably the organic industry-funded Environmental Working Group (EWG), will protest that this conservative regulatory regime is inadequate. Knowing its target audience, concerned consumers, aren't familiar with the finer points of federal pesticide regulation, EWG sets artificially low standards for pesticide residues in food. It then tells the public that EWG scientists detect pesticide residue levels in food that aren't “protective of children’s health….”
Compare the standards employed by food safety agencies all over the world to EWG's loosey-goosey metric. The former is designed to establish reasonable estimates for safe pesticide exposure; the latter is meant to instill uncertainty and fear in parents who want to protect their kids.
The new study also examined how the press relays pesticide safety information to consumers. What reporters leave out of their stories, it turns out, is arguably just as important as what they include. Or as the authors put it, these stories "lack details that handicap accurate interpretation of the results..."
For example, popular media reports about glyphosate in food typically lack any analysis of the testing method used and whether its results are reliable. This robs readers of the opportunity to verify the conclusions they see in news stories, which is necessary given the media's spotty track record on food safety reporting. The study's lead author Dr. John Vicini put explained the problem in an email:
If you had a test in a hospital for blood glucose or Covid-19 you would like to know that the sample was collected properly, that there was the required medical history and purpose associated with the patient, that the sample was properly stored, that the assay [test] used was properly conducted by a trained analyst, that the instrumentation was properly maintained and calibrated and that the result was properly interpreted.
If you were told that your blood glucose was 300 or that your covid test was negative, you should have assurance that the results are accurate and be given a proper conclusion as to what those numbers mean. This should be the same expectation of residue detection studies performed on pesticides, like glyphosate.
To complicate the matter further, reporters often use ambiguous language that implies significant risk exists where there is actually very little. “Unfortunately, many of the popular press reports are accompanied by value-judgment words like 'high' or 'contaminate,'” the study authors wrote. In short, this dearth of testing information means reporters often describe inconsequential amounts of pesticide residue in food as too high and fail to report how the numbers were obtained.
Final thoughts: countering the propaganda
While activists and reporters deserve our skepticism for misleading everyone about pesticides, there's one group that could do a lot to counteract the alarmism: health care providers. “The people that consumers look to for food safety advice (e.g., health care professionals, nutritionists, and dietitians) should have scientifically balanced information needed to discuss the topics of [pesticide] residues,” the authors argued. “However, current training curricula for these professions have limited, if any, coursework on relevant topics.” As one doctor put it on Twitter:
This isn't a swipe at health care providers; their work is invaluable. But if they don't know how regulators assess pesticide safety, they can't pass on reliable information to their patients. This is indicative of a much larger problem. If bloggers at LiveLoveFruit and many highly trained physicians are uninformed, then most people in between them probably have the same limited understanding. And that means the pesticide propaganda from EWG and other groups won't cease until society develops more science literacy.