“There’s no risk to human health. Residue levels are well below the Acceptable Daily Intake.”
That’s the line repeated by regulatory bodies from New Zealand’s MPI to Australia’s FSANZ and the US EPA. It’s meant to be reassuring. After all, if the science says glyphosate is safe in small doses, why worry?
But here’s the question we keep coming back to:
Who decides what “acceptable” really means — and how up to date is that science?
In this article, we unpack the concept of the Acceptable Daily Intake (ADI), where it comes from, and why it may no longer be fit for purpose in a world where chronic low-level chemical exposure is the norm, not the exception.
Because when it comes to glyphosate — and many other industrial chemicals — what’s legally acceptable may not be biologically safe.
What Is an ADI — and Who Sets It?
The Acceptable Daily Intake (ADI) is often presented as a scientific fact — a clean, trustworthy number that tells us how much of a chemical we can safely consume every day over a lifetime. In reality, it’s not quite that simple.
An ADI is a regulatory estimate, usually expressed in milligrams per kilogram of body weight per day (mg/kg/day). It’s meant to represent the amount of a substance you could ingest daily without any “appreciable risk” to your health.
In New Zealand, the ADI for glyphosate is currently 0.3 mg/kg/day, set by Food Standards Australia New Zealand (FSANZ) — not MPI directly — and it hasn’t been reviewed in decades.
But here’s where it gets interesting — and murky.
The ADI is usually based on animal studies, often conducted decades ago. Scientists identify the highest dose at which no adverse effects are observed (called the NOAEL — No Observed Adverse Effect Level), then apply a series of safety factors — typically 100-fold — to come up with a supposedly safe human dose.
So, if rats showed no effects at 10 mg/kg/day, the ADI might be set at 0.1 mg/kg/day.
Sounds cautious, right?
But there are two things worth knowing:
- These studies are almost always supplied by industry, not independent researchers.
- They focus on short-term, visible outcomes like organ damage or weight changes — not subtle, long-term effects like hormone disruption, gut microbiome changes, or epigenetic shifts.
As mentioned above, New Zealand’s ADI for glyphosate is currently 0.3 mg/kg/day — a figure we share with Australia. But look around the world, and you’ll find that other countries don’t always agree.
The European Food Safety Authority (EFSA), for example, has proposed lowering glyphosate’s ADI to 0.1 mg/kg/day — and some experts think even that might be too generous given what we now know about low-dose and cumulative effects.
So who decides what’s safe? It depends where you live — and whose science your regulators are willing to trust.
The Problem with ADIs
On the surface, ADIs sound reassuring — a scientific buffer zone between what’s tested in animals and what’s allowed for humans. But dig a little deeper, and the cracks begin to show.
1. Based on Outdated Science
Most ADIs for glyphosate were set decades ago, using traditional toxicology models that don’t reflect the latest understanding of how chemicals interact with the human body. They assume that if high doses don’t cause visible harm, lower doses must be safe. But that assumption is now being challenged by a growing body of research into endocrine disruption, epigenetics, and microbiome impacts — none of which were part of the original risk assessments.
2. Built on Industry-Funded Data
It’s no secret: the studies used to set ADIs are often submitted by the very companies that make the chemicals. Regulators typically don’t conduct their own experiments — they review industry-supplied dossiers. And while safety factors are applied, the foundation itself may be compromised by conflicts of interest, unpublished data, or methodologies designed to avoid detecting harm.
3. The “One Chemical at a Time” Problem
ADIs are calculated in isolation. They don’t account for real-world exposures to multiple chemicals — which is how we actually live. What happens when glyphosate residues are consumed alongside other herbicides, food additives, or pharmaceutical residues? We don’t know — and the ADI doesn’t try to answer that.
4. Not Designed for Endocrine Disruptors
Hormone-disrupting chemicals like glyphosate don’t behave like traditional poisons. They can cause harm at incredibly low doses — sometimes lower than the so-called “no-effect” levels identified in animal studies.
That means traditional safety testing — which looks for harm at high doses and assumes less risk as the dose drops — can completely miss effects that occur only at very low, hormonally active levels.
This throws a spanner in the old toxicology rule: “the dose makes the poison.” When it comes to hormones, the timing, frequency, and life stage of exposure may matter more than the amount.
5. Vulnerable Populations Aren’t Properly Considered
An ADI assumes a healthy adult body — not a developing fetus, a breastfeeding infant, or someone with compromised detox pathways. And yet everyone is exposed under the same regulatory threshold. Is it ethical to base our safety limits on the average, when some populations may be more vulnerable to harm?
The Emerging Science
For years, regulators have insisted that glyphosate is safe at low levels — as long as it stays below the Acceptable Daily Intake (ADI). But a wave of new research is challenging that assumption.
1. Low Doses Can Still Do Harm
We’re learning that lower isn’t always safer — especially when it comes to chemicals that act as endocrine disruptors. These substances can interfere with hormone function in ways that don’t follow traditional toxicology rules. In fact, some studies show that tiny amounts of glyphosate may cause changes in reproductive development, liver function, and gut health — even when high doses show no effect.
This is known as a non-monotonic dose response — meaning the relationship between dose and effect doesn’t follow a straight line. It’s messy, complex, and hard to predict. But it’s real — and it’s been observed in peer-reviewed research across multiple biological systems.
2. Timing Matters More Than Quantity
Exposure during critical windows — like fetal development, infancy, or puberty — may have lasting effects even if the overall dose is small. That’s not something current ADIs account for. They’re based on average lifetime exposure, not on how short bursts of glyphosate at the wrong time might shape health for years to come.
3. Early Findings on the Gut Microbiome
Emerging research suggests glyphosate may also disrupt the gut microbiome — the community of beneficial bacteria essential for digestion, immunity, and even mental health. These microbes are sensitive, and even low-level glyphosate residues in food may act as an antibiotic, killing off key strains.
For instance, a 2021 study found glyphosate exposure at parts-per-billion levels altered gut microbial composition in rats — effects not captured in traditional risk assessments.
Again, none of this is factored into the ADI equation.
4. Epigenetics and Generational Effects
There’s also concern that glyphosate could cause heritable epigenetic changes — meaning exposure today might affect future generations, not just the individual exposed. This field is still developing, but the early signals are worrying.
Regulators may still be quoting decades-old thresholds, but the science is moving on — and it’s raising uncomfortable questions about what “safe” really means in a chemically saturated world.
ADI ≠ Cumulative Risk
The Acceptable Daily Intake might sound like a comprehensive safety net — but it’s not designed to protect against the kind of real-world exposure most of us now face.
1. One Chemical at a Time Doesn’t Reflect Real Life
ADIs are calculated in isolation. They assume you’re only exposed to one chemical at a time, in controlled doses, through a single route (usually diet). But in reality, we’re exposed to cocktails of chemicals every day — from food, water, air, cosmetics, packaging, and more.
So even if glyphosate alone is deemed “safe” at 0.3 mg/kg/day, what happens when it interacts with other pesticides, preservatives, or hormone-disrupting compounds? ADIs don’t ask that question — and regulators rarely test for synergistic effects.
2. No Accounting for Daily Background Exposure
Glyphosate has been detected in waterways, soil, honey, bread, and even human urine. That means exposure isn’t just dietary — it’s environmental. But the ADI only considers food residues. It doesn’t factor in what’s already building up in your body from other sources.
In our own food testing, glyphosate has shown up in honey and cereals — foods consumed daily by children and adults alike.
3. Vulnerable Populations Are Left Out of the Equation
The ADI is based on the assumption that a healthy adult can tolerate a certain dose every day without harm. But children, pregnant women, the elderly, and those with chronic illnesses may be more sensitive to chemical exposures — and yet they’re held to the same standard.
For example, a child may be eating more food relative to their body weight — and have a less developed ability to detoxify chemicals. Should they be treated the same as a 70 kg adult with a fully developed liver? The ADI says yes. Common sense says maybe not.
An ADI might give you a legal threshold — but it doesn’t give you the full picture.
4. Cumulative Effects Over Time Aren’t Considered
ADIs also ignore the cumulative biological effects of repeated low-dose exposure. What if a tiny amount each day builds up over decades? What if long-term exposure affects gene expression, organ function, or cancer risk — in ways that aren’t captured by short-term animal tests?
In other words, an ADI might give you a legal threshold — but it doesn’t give you the full picture. It’s a starting point, not a guarantee. And in the case of glyphosate, it may be dangerously out of date with what science now knows.
Is New Zealand’s ADI Outdated?
New Zealand’s Acceptable Daily Intake (ADI) for glyphosate is currently set at 0.3 mg per kilogram of body weight per day. This figure is shared with Australia, and it hasn’t changed in over two decades.
But science has moved on — and some regulators overseas are starting to take notice.
1. Europe Is Reconsidering
The European Food Safety Authority (EFSA) has proposed lowering the ADI to 0.1 mg/kg/day, based on updated toxicological assessments. Even that figure is controversial, with independent scientists arguing it still doesn’t go far enough to reflect the risks of long-term, low-dose exposure.
So why is New Zealand sticking with a higher number?
2. No Local Transparency or Public Review
Unlike Europe, which periodically reassesses ADIs in light of emerging science and stakeholder input, New Zealand’s process is far less transparent. There’s been no recent public review of the glyphosate ADI, and no new dietary exposure survey since 2015/16 — despite major international lawsuits, mounting evidence of biological effects, and a public increasingly concerned about what’s in their food.
FSANZ, which sets the ADI for New Zealand, has not made recent reviews of glyphosate publicly available — and unlike Europe, it does not routinely publish detailed reassessments for public input.
3. Regulatory Inertia or Industry Influence?
Maintaining the status quo is often easier than challenging it — especially when powerful agricultural interests rely on glyphosate as a tool of convenience. But when scientific understanding changes and regulatory limits don’t, it raises a troubling question: Are our policies based on health, or habit?
4. The ADI Is Only as Good as the Data Behind It
If New Zealand’s ADI is based on outdated science, limited studies, or assumptions that no longer hold up, then it may be giving the public a false sense of safety. And if it hasn’t been reevaluated with today’s science in mind, how can we trust it?
In short, yes — New Zealand’s ADI for glyphosate is likely outdated. And until it’s revisited transparently, with public input and modern science in hand, we’re all being asked to trust a number that may no longer mean what it once did.
Rethinking “Safe” in a Changing World
Regulations are meant to protect us. But when those regulations rely on outdated assumptions, industry-supplied data, and one-size-fits-all thresholds, they may offer reassurance more than real safety.
The Acceptable Daily Intake (ADI) for glyphosate is a perfect example. It’s a number we’re told to trust — a figure used to justify residue levels in bread, oats, honey, and countless other foods. But it doesn’t reflect modern science. It doesn’t account for gut disruption, hormonal shifts, or vulnerable populations. And it certainly doesn’t speak to the cumulative reality of life in a chemically saturated environment.
So when MPI tells us that raising glyphosate residue limits is fine — because we’re still “well below the ADI” — we have to ask:
Is the ADI still relevant? Or is it just a convenient excuse to keep glyphosate in circulation?
Because if our definition of “safe” hasn’t kept up with the science, then maybe it’s time we stop trusting the number — and start questioning the system that created it.
If the rules aren’t protecting us, maybe it’s time we demand new ones.
Resources & References
We’re often told to “trust the science” — but which science, and whose?
The resources below offer a deeper look into how Acceptable Daily Intakes are determined, why they may be outdated, and what emerging research is revealing about glyphosate’s real-world impact. If you’re curious, questioning, or simply want to make more informed choices, start here.
Raising MRLs Threatens Public Health
Why increasing glyphosate residue limits isn’t just a technical tweak — it could have real health consequences for all New Zealanders.
Gene Technology and the Glyphosate Connection
Explores the link between higher residue allowances and the push to legalise genetically modified crops engineered to tolerate glyphosate.
Glyphosate in Bread: Why We’re Testing It
Our independent food testing series began with five supermarket loaves. The results raise serious questions about what we’re really eating.
Glyphosate in Honey: Contamination Close to Home
Shows how glyphosate use in surrounding landscapes can affect even the most natural, “clean” products like local honey.
External References
FSANZ – How Exposure to Chemicals in Food Is Assessed
FSANZ outlines how Acceptable Daily Intakes (ADIs) are used to evaluate chemical safety in food — and why these limits may not reflect long-term, low-dose effects.
EFSA – Glyphosate Reassessment Report
The European Food Safety Authority’s latest scientific opinion on glyphosate, including proposed changes to the ADI.
Endocrine Society – Endocrine-Disrupting Chemicals
A global scientific consensus that low-dose exposures to hormone-disrupting chemicals can pose significant health risks — even when they fall within regulatory limits.
Oxford University Press: Hormones and Endocrine Disrupting Chemicals: Low-Dose Effects and Nonmonotonic Dose Responses
A landmark review showing how chemicals like glyphosate may cause harm at levels previously considered safe, challenging the foundations of modern toxicology.
Beyond Pesticides – Endocrine Disrupting Chemicals and the Myth of “Safe” Levels
Endocrine disruptors don’t follow the old toxicology model — they can cause harm at levels below those considered “safe,” especially when exposure is chronic, cumulative, and occurs during vulnerable life stages.
Because when it comes to food safety, the most dangerous assumption is that someone else is watching.
We invite you to keep digging, keep asking questions — and help shift the conversation toward transparency, accountability, and real protection.
Image Source & Attribution
The feature image on this page was created using canva.com
