Something strange keeps happening on social media.
Celebrities, influencers, and ordinary travelers return from weeks in France, Italy, or Spain and report the same astonishing thing: they ate gluten. They drank wine at noon. They had croissants for breakfast and pizza for dinner, and they felt (inexplicably, wonderfully) fine. Americans who cannot touch a slice of white bread at home without hours of regret describe wandering through Roman markets eating fistfuls of pasta with zero consequence.
The reflexive explanation has always been stress, portion size, mindfulness, or the romantic power of vacation. But a quieter, more uncomfortable theory has begun to circulate among scientists, epidemiologists, and food safety researchers, and it deserves to be taken seriously, not as settled fact, but as a hypothesis the evidence is beginning to support.
What if American food (not just its additives and its dyes and its high-fructose corn syrup) but the very soil it grows in, is harboring microbial threats that European soil is not?
I. The Sludge Beneath Our Feet
Begin with a fact so mundane it borders on invisible: the United States spreads human sewage on its farmland.
The EPA estimates that approximately 2.39 million dry metric tons of treated sewage sludge (renamed “biosolids” by an industry that understood the marketing problem) were applied to American crop fields in 2024 alone. Roughly 60 percent of the nation’s sludge ends up on agricultural land each year.
The nutrients in sludge are genuine. Nitrogen, phosphorus, and potassium make crops grow, and farmers in an era of expensive synthetic fertilizer welcomed a free or cheap alternative. What arrived with it, science is now documenting in disturbing detail, is something else entirely.
“The pathogen risks from land application of sewage sludge have never been adequately evaluated. We are, in the most literal sense, eating in the dark.”
Sewage sludge is not simply fertilizer. It is a mixture of human waste, industrial discharge, hospital effluent, pharmaceutical residue, road runoff, personal care products, and heavy metals. Processing (heat drying, composting, anaerobic digestion) can reduce some pathogens. It does not eliminate them, and it does not touch PFAS “forever chemicals,” antibiotic resistance genes, endocrine disruptors, or hundreds of industrial compounds the EPA has documented but does not regulate in sludge.
The EPA has catalogued 726 chemicals in biosolids since testing began in 1993. The more than 9,000 PFAS compounds are not among the substances required to be tested.
Peer-reviewed research published in Environmental Health Perspectives found that residents living near biosolid application sites reported “a prevalence of Staphylococcus aureus infections of the skin and respiratory tract” following exposure to winds blowing from treated fields. A documented outbreak of staph infections traced to a single land-application site in Robesonia, Pennsylvania saw eight of nine residents in one household contract infections over a five-year period.
A model published in Environmental Health Perspectives in 2008 found that the public health risk from exposure to pathogens in biosolids had, at that point, never been quantitatively assessed, because no appropriate model and no systematic exposure data existed. A 2002 National Research Council committee reached an almost identical conclusion. That finding has not materially changed in the two decades since.
By the numbers:
4 million dry metric tons of sewage sludge generated annually by U.S. wastewater plants (EPA, 2024)
~70 million acres of U.S. farmland potentially tainted by biosolid-derived chemicals, per Environmental Working Group estimates
4.5 billion pounds of sludge spread on farm fields or used in compost in 2023 alone
27 states had no existing or proposed legislation on PFAS in biosolids, per a 2023 survey of states
II. Antibiotic Resistance Growing in the Crop Field
The biosolids problem intersects with a second and perhaps more alarming development: the emergence of antibiotic-resistant pathogens not in hospitals, but in agricultural soil itself, bred in part by the routine application of antibiotics directly to crops.
The U.S. EPA has approved antibiotics for direct application as pesticides on American crops. Streptomycin and oxytetracycline, both medically critical antibiotics in humans, have been sprayed on hundreds of thousands of acres of citrus in Florida and California and on fruit trees across much of the country. The U.S. Geological Survey estimated more than 125,000 pounds of these antibiotics were applied to crops in 2018 alone.
In 2025, a coalition of public health and farmworker organizations filed an emergency petition asking the EPA to cancel all such registrations, citing CDC data submitted to the agency in 2017 showing that agricultural spraying of these antibiotics could select for resistant bacteria in environmental settings.
The mechanism is not subtle. As a 2024 review summarized:
“In almost every region where streptomycin has been used to control bacterial diseases in the United States, bacterial populations resistant to this antibiotic have been detected.”
Pesticide stress, separate research found, enhances the acquisition of antibiotic resistance through several routes: activating efflux pumps that flush antibiotics out of bacterial cells, inhibiting outer membrane pores through which antibiotics enter, and inducing gene mutations. Crucially, pesticides also appear to promote the transfer of antibiotic resistance genes between bacteria by increasing cell membrane permeability.
The World Health Organization now reports that one in six confirmed bacterial infections worldwide in 2023 was resistant to antibiotic treatment, and that resistance rose in more than 40 percent of monitored pathogen-antibiotic combinations between 2018 and 2023, at an annual rate of 5–15 percent.
The question is not whether antibiotic-resistant organisms are present in American agricultural soil. The question is how much of what we eat carries them, and whether our guts are simply failing to tell us in a language we recognize as illness.
III. A Regulatory Divide That May Explain a Lot
The contrast with Europe is not incidental. It is structural.
The European Union operates under the precautionary principle: substances that show evidence of potential harm are restricted until proven safe. The United States inverts this logic: additives and agricultural chemicals are generally permitted unless harm is conclusively demonstrated.
The result is a specific and enumerable list of substances Americans eat that Europeans do not:
SubstanceUnited StatesEuropean UnionGlyphosate (pre-harvest)Permitted on 70+ crops, days before harvestPre-harvest use prohibited EU-wide since 2023Streptomycin (antibiotic pesticide)Approved for citrus, apples, pearsBanned or heavily restrictedBiosolids on cropland~60% of sludge land-applied; minimal testingStricter standards; nations moving toward prohibitionPotassium bromate (bread)PermittedBannedAzodicarbonamide (dough conditioner)PermittedBannedrBGH / rBST (dairy growth hormone)PermittedBannedChlorpyrifos (insecticide)Use continuesBanned
Glyphosate deserves particular attention in the context of gut health. The herbicide works by blocking the shikimate pathway, an enzyme system present in plants and bacteria but not in human cells. Regulators long cited that absence as evidence of safety.
But the bacteria in the human gut do use the shikimate pathway.
Animal and cell studies suggest glyphosate exposure alters gut flora balance and intestinal integrity, which may amplify the symptoms many Americans attribute vaguely to “food sensitivities.” In the U.S., allowable glyphosate residue limits in food have actually been raised in recent years to accommodate pre-harvest desiccation practices. In Europe, pre-harvest spraying onto food crops is not permitted.
IV. What This Might Mean, and What It Doesn’t
To be rigorous: the celebrities eating baguettes without incident in Paris are not evidence. Anecdote is not data. Vacation eliminates stress, changes eating patterns, shifts sleep, and alters mood, all of which affect digestion independently of anything in the food itself. The “I can eat gluten in Europe” phenomenon could have a dozen explanations, most of them banal. There is also something related to changing environments and a shift in immune reactivity.
But the underlying scientific question, whether the microbial environment of American agricultural soil has been meaningfully altered by decades of biosolid application, antibiotic pesticide use, and comparatively permissive chemical regulation, is not banal. It is a legitimate and largely uninvestigated hypothesis.
The regulatory frameworks that would generate systematic answers do not yet exist. Most states have no testing requirements for PFAS or antibiotic resistance genes in biosolids. The EPA has catalogued 726 chemicals in sludge and does not require monitoring for most of them. The CDC submitted data to the EPA in 2017 documenting resistance risks from agricultural antibiotic spraying, and the EPA approved expanded use anyway.
The biosolids contamination of American farmland could be one mechanism. The proliferation of antibiotic-resistant organisms in pesticide-treated soil could be another. The additive burden (the cumulative effect of compounds banned elsewhere but routinely consumed here) is a third. None of these explanations is complete on its own. And the honest answer, the one that should unsettle everyone who has eaten a meal in this country today, is that we do not actually know which of them, or which combination, is bearing weight.
Science does not yet have the full picture. But the shape of what is emerging (the scale of biosolid application, the documented presence of antibiotic-resistant pathogens in agricultural environments, the widening regulatory gap between the U.S. and Europe) suggests that the social media travelers posting disbelievingly from Italian tables may be pointing, inadvertently, at something real.
Their bodies, apparently, noticed a difference.
Perhaps it is time for our regulatory agencies to start looking for one too.
Sources: U.S. EPA Biosolids Annual Reports (2024); Environmental Working Group; Lewis et al., Environmental Health Perspectives (2002); Eisenberg et al., Environmental Health Perspectives (2008); Beyond Pesticides (2024, 2025); WHO Global Antimicrobial Resistance Surveillance (2024); Environmental Council of the States (2023); ANSI Blog on EU/US food standards; Science Insights.
This piece presents one scientific hypothesis among several possible explanations for reported cross-Atlantic differences in food tolerance. It does not constitute medical advice.