Glyphosate in bread & honey, latest research
No More Glyphosate NZ has been doing valuable work showing us that unfortunately glyphosate (Roundup), the most widely used herbicide in the world, is common in NZ bread and honey, and has also been found in Weet-Bix and breakfast cereal. Something to note: gluten-free bread and gluten-free Weet-Bix also had residues detected.
Glyphosate in NZ honey has now been detected in 65% (30/46) of samples. This testing of honey is the largest independent dataset on glyphosate residues in NZ retail honey. The bees are doing the environmental sampling for us. This is a concern not only for us as consumers but also for those who export premium health-boosting manuka and kanuka honey.
The latest batch of bread that No More Glyphosate has tested had all four loaves of Ploughman’s showing up with glyphosate residues, including the gluten free one. We can understand that when glyphosate is used just before harvest to make it easier to get the wheat, residues are likely to occur. But when there is no wheat involved, we don’t know how the residues can happen.
Glyphosate - known effects on humans
How common is glyphosate in the human body? What problems has recent research in humans found? Do low levels in our food matter?
How common is glyphosate in the human body?
Briefly, quite common. Recent reviews report that glyphosate has been detected in 60% to 80% of the general population, including children, when urine samples are tested (Galli 2024). It has also been detected in blood, breast milk, semen and other bodily fluids. Most people tested today have small amounts of glyphosate in their bodies, usually detected in urine, indicating recent exposure. Exposure has increased dramatically around the world.
Some problems found in recent research
Recent animal and laboratory studies have linked glyphosate exposure to cell damage, fertility problems, hormone disruption, nervous system effects, changes in gut bacteria, immune-system effects, and DNA damage. However, there is ongoing debate about how well these findings predict health effects in humans at the levels people may be exposed to. Typically regulatory authorities will assume a substance is innocent until there is incontrovertible evidence to the contrary.
In the last five years, however, strong evidence from human studies show various effects from glyphosate exposure, including oxidative stress biomarkers, reproductive-health effects, and possible neurological and endocrine-related effects.
Oxidative stress is like wear and tear on the body's cells. Or, to explain it in another way, just as a sliced avocado slowly turns brown, oxidative stress is a process that can gradually damage cells in the body. Too much of it can damage cells and has been linked to a range of health problems, such as cancer, heart disease, infertility and diseases that affect the brain.
A 2023 study of American farmers found that those with higher levels of glyphosate in their bodies also showed more signs of cell damage, or oxidative stress (Chang 2023).
In one of the largest studies of pregnant women, published in 2026, researchers found that glyphosate may increase the risk of babies being born too early (Herrera 2026).
A 2024 study found glyphosate in the semen of infertile men and linked it to higher levels of cell damage, suggesting it may affect male fertility and those of future generations (Vasseur 2024).
A 2022 review has concluded that glyphosate can affect the brain and nervous system in humans and animals, even at levels currently considered safe by regulators (Costas-Ferreira 2022).
Do low levels of glyphosate in food matter?
Because glyphosate is so widely used around the world, it can now be found not only in our food but also in the environment and our bodies, in dramatically higher amounts than in the past.
While regulatory authorities may maintain that trace food residues are perfectly safe, independent scientific studies are raising serious red flags. Increasing human, laboratory and animal research reveals that exposure to glyphosate may lead to various adverse effects.
Because glyphosate exposure is so common and typically occurs over many years, even low levels deserve careful attention, it can be argued. What are the possible effects of small amounts being consumed repeatedly over a lifetime? This is not taken into account. Nor the typical cocktail of chemicals that we may be exposed to daily in the food we eat.
The glyphosate controversy exposes systemic flaws in pesticide regulation, highlighting the urgent need for independent safety evaluations. As Bloem and others put it in 2024:
"The debate about glyphosate…highlights the shortcomings of regulatory processes."
To restore trust in decisions about problematic substances such as glyphosate made by regulatory authorities, future research must be funded by manufacturers through neutral intermediaries, peer-reviewed, and made completely public (Bloem 2024). Unfortunately, both the European Food Safety Authority (EFSA) and New Zealand’s own regulatory authorities have fallen short of these standards in their past reviews.
During the NZ EPA’s reassessment of chlorpyrifos, for example, it was alarming to see the exclusion of all peer-reviewed studies regarding its neurotoxicity and its impact on children’s brain development through food consumption, a consideration that had caused 44 other countries to ban it before NZ eventually did so for food use in January 2026...
In the meantime, as informed consumers, if we want to take a precautionary approach and avoid glyphosate and other problematic substances, choosing organic food where possible can help reduce our exposure, while also lessening the chemical burden on the environment.
References
Bloem, B. R. et al (2024). Glyphosate and neurotoxicity - a call for scientific renewal. Nature Reviews Neurology, 20(3), 131-132.
Chang VC et al, (2023) Glyphosate exposure and urinary oxidative stress biomarkers in the Agricultural Health Study.Journal of the National Cancer Institute, 115(4), 394-404.
Costas-Ferreira C, Durán R, Faro LRF (2022). Toxic Effects of Glyphosate on the Nervous System: A Systematic Review. Int J Mol Sci. Apr 21;23(9):4605. doi: 10.3390/ijms23094605. PMID: 35562999; PMCID: PMC9101768.
Galli FS, et al (2024). Overview of human health effects related to glyphosate exposure. Front Toxicol. Sep 18;6:1474792. doi: 10.3389/ftox.2024.1474792. PMID: 39359637; PMCID: PMC11445186.
Herrera, T. et al. (2026). Associations of glyphosate exposure in pregnancy with preterm birth: A longitudinal birth cohort study. Environmental Pollution, 408, 128775.
Vasseur, C et al. (2024). Glyphosate presence in human sperm: First report and positive correlation with oxidative stress in an infertile French population. Ecotoxicology and Environmental Safety, 281, 116640.
Alison White October 2026
