GM Free Cymru

Reduction in urinary organophosphate pesticide metabolites in adults after a week-long organic diet

Date Added to website 4th May 2014

by Liza Oates,Marc Cohen, Lesley Braun, Adrian Schembri, Rilka Taskova Environmental Research132(2014)105–111

[ Comment from GM-Free Cymru: This is another paper which confirms the anecdotal evidence relating to the negative health effects of organophosphate pesticides like glyphosate -- showing that there is significant "OP pesticide exposure" in adults on a "normal diet" and a dramatically reduced exposure when the same individuals switch to an organic diet. This was a small study with large implications. Of course, OP exposure and traces of metabolites in urine do not in themselves indicate negative health effects -- but the evidence that "normal diets" (especially in the US) are associated with damaged health is piling up all the time -- as are the indications that for many ailments the way to get better is simply to switch to organically produced food, which is entirely or largely free of chemical residues.]


Background: Conventional food production commonly uses organophosphate (OP) pesticides, which can have negative health effects, while organic food is deemed healthier because it is produced without these pesticides. Studies suggest that organic food consumption may significantly reduce O P pesticide exposure in children who have relatively higher pesticide exposure than adults due to their different diets, bodyweight, behaviour and less efficient metabolism.

Objectives: A prospective, randomised, crossover study was conducted to determine if an organic food diet reduces organophosphate exposure in adults.

Methods: Thirteen participants were randomly allocated to consume a diet of at least 80% organic or conventional food for 7days and then crossed over to the alternate diet. Urinary levels of six dialkylphosphate metabolites were analysed in first-morning voids collected on day 8 of each phase using GC–MS/MS with detection limits of 0.11–0.51 μg/L.

Results: The mean total DAP results in the organic phase were 89% lower than in the conventional phase (M¼0.032 [SD ¼0.038] and 0.294 [SD ¼0.435] respectively, p¼0.013). For total dimethyl DAPs there was a 96%reduction (M¼0.011 [SD¼0.023] and 0.252 [SD¼0.403] respectively, p¼0.005). Mean total diethyl DAP levels in the organic phase were half those of the conventional phase (M¼0.021 [SD¼0.020] and 0.042 [SD¼0.038] respectively), yet the wide variability and small sample size meant the difference was not statistically significant.

Conclusions: The consumption of an organic diet for one week significantly reduced OP pesticide exposure in adults. Larger scale studies in different populations are required to confirm these findings and investigate their clinical relevance.