By Josefine Pettersson
The results of a randomised controlled dietary intervention trial found that pesticide exposure was significantly decreased when participants changes from a conventional to an organic diet by over 90%.
The study was a joint venture with University collaboration from multiple institutions, most notably Newcastle University with Leonidas Rempelos as the main contributor. The experiment was a two-week randomised intervention trial with 27 participants who were allocated a fully organic or conventional diet.
The trial focused on the Urinary Pesticide Residue Excretion (UPRE) of the two groups. The comprehensive study design was multifaceted to ensure results could be attributed to the changes in diet of participants. Participants from the UK consumed a conventional Western Diet, before flying to Greece and consuming a controlled organic or conventional Mediterranean diet, followed by an additional two weeks of conventional Western food back in the UK.
All food samples were assessed for 492 different active ingredients used within crop protection products. From this, all identified plant growth regulators, including herbicides, insecticides and fungicides that were present in the food were monitored for in participants’ urine consistently through the experiment. It was found that the UPRE was 91% lower with an organic compared to a conventional diet. The remaining ~9% was attributed to environmental exposure through mosquito repellent.
What is the situation in Australia?
The study was prompted from a significant number of crop samples containing pesticide residues (as mentioned above) that are allowed for use on crops within the EU. Maximum Residue Limits (MRLs) are the highest amount of an agricultural or veterinary chemical residue that is legally allowed in a food product (NOTE: within Australia, MRLs are overseen by Food Standards Australia (FSANZ)). Certified Organic MRLs are 10% or less of that allowed within FSANZ. 10% or less is noted as nearly all of the 900+ chemicals approved for use in conventional agriculture in Australia, that are not allowed for use within certified organic production systems.
What does this mean for you as a consumer?
Many of the pesticides detected in urine and foods are neurotoxic (neonicotinoids and organophosphates) or confirmed endocrine-disrupting chemicals and can have activity at very low concentrations. A study by Sørensen et al. (2006) also showed Chlormequat Chloride, a common growth regulator and a suspected Endocrine disruptor, was also linked to reduced fertility in animals including breeding sows. Many other studies showing the negatives effects associated with pesticide exposure were also cited within the article. The study also highlighted that increasing the amount of conventional fruit and vegetables in the diet increased the levels of insecticides and organophosphate exposure of the participants.
This is the first study of its kind to show that switching from a conventional to a fully organic diet can reduce exposure to all classes of pesticides including herbicides, insecticides, fungicides, growth regulators, organophosphates, and pyrethroids. The decrease in pesticide exposure may explain the positive health outcomes linked to organic food consumption cited in the study.
So, when making healthy food changes, remember to buy organic produce!
Please note: This study was conducted in Europe and may not be a true reflection of agricultural practices within Australia.
The American Journal of Clinical Nutrition, nqab308, https://doi.org/10.1093/ajcn/nqab308
© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.