Diet and food type affect urinary pesticide residue excretion profiles in healthy individuals: results of a randomized controlled dietary intervention trial

Abstract

Background Observational studies have linked pesticide exposure to various diseases, whereas organic food consumption has been associated with positive health outcomes. Organic farming standards prohibit the use of most pesticides, and organic food consumption may therefore reduce pesticide exposure. Objectives To determine the effects of diet (Western compared with Mediterranean) and food type (conventional compared with organic) and sex on urinary pesticide residue excretion (UPRE), as well as associations between specific diet components and UPRE. Methods In this 2-wk, randomized dietary intervention trial, healthy adults were randomly allocated to an intervention (n = 13) or conventional (n = 14) group. Whereas participants in the intervention group consumed a Mediterranean diet (MedDiet) made entirely from organic foods, the conventional group consumed a MedDiet made entirely from conventional foods. Both groups consumed habitual Western diets made from conventional foods before and after the 2-wk intervention period. The primary outcome was UPRE. In addition, we assessed diet composition and pesticide residue profiles in foods eaten. Participants were aware of group assignment, but the study assessors were not. Results During the intervention period, total UPRE was 91% lower with organic (mean 17 μg/d; 95% CI: 15, 19) than with conventional (mean 180 μg/d; 95% CI: 153, 208) food consumption (P < 0.0001). In the conventional group, switching from the habitual Western diet to the MedDiet increased insecticide excretion from 7 to 25 μg/d (P < 0.0001), organophosphate excretion from 5 to 19 μg/d (P < 0.0001), and pyrethroid residue excretion from 2.0 to 4.5 μg/d (P < 0.0001). Small but significant effects of sex were detected for chlormequat, herbicide, and total pesticide residue excretion. Conclusions Changing from a habitual Western diet to a MedDiet was associated with increased insecticide, organophosphate, and pyrethroid exposure, whereas organic food consumption reduced exposure to all groups of synthetic chemical pesticides. This may explain the positive health outcomes linked to organic food consumption in observational studies. This trial was registered at www.clinicaltrials.gov as NCT03254537.

Integrated Soil and Crop Management in Organic Agriculture: A Logical Framework to Ensure Food Quality and Human Health?

“…Specifically, conventional fruits were found to have substantially higher pesticide loads than conventional vegetables and cereal-based foods, whereas contamination levels were similar in organic fruits, vegetables and cereal-based foods, but substantially lower than in their conventional comparators (Figure 7a). Similar results were obtained in recent retail surveys of fruits, vegetables and cereal-based foods [141], which reported that the number of different pesticide residues detected was substantially higher in conventional products, compared with organic fruit, vegetables and cereal-based food products (Figure 7b). A large retail survey of wheat flour products carried out over 3 years in the UK and Germany reported significant effects of wheat species (Triticum aestivum L. vs. T. spelta L. flour) and refining (white versus whole-grain flour) and the country in which flour samples were collected (the UK versus Germany), on pesticide residue concentrations in conventional, but not organic wheat flour, which generally contained very low pesticide residues [140] (Figure 8).…”

“…Several dietary intervention studies with humans and some human cohort studies have assessed the effect of organic versus conventional food consumption on urinary excretion of pesticide residues, but there is limited data on urinary excretion of other health relevant compounds (e.g., phenolics, other phytochemicals, antioxidants and mineral micronutrients). These studies have consistently shown that organic food consumption results in significantly lower exposure to a range of pesticides, but identified no or only very small effects on the urinary excretion of other health relevant compounds [141,168,169,[185][186][187][188][189][190]; this evidence has been described and discussed in detail in a recent systematic review by Vigar et al [169].…”

“…However, as described in Section 2.3.5 above, organic farming standards permit the use of pesticide products made from (i) mined minerals (S, Cu), (ii) microbial fermentation extracts, and (iii) plant extracts [4,111]. In this section, we therefore summarize the currently available information of the effect of organic vs conventional production protocols on pesticide residues in crops [57,[137][138][139][140][141].…”

“…The most controlled (during the 2-week intervention period participants consumed either only certified organic or only conventional foods) and comprehensive (in terms of the range of pesticides monitored) dietary intervention study estimated that changing to organic food consumption can reduce total pesticide exposure by more than 90% [141]. Interestingly, the same study also found that switching from habitual Western diets (with high meat and low fruit and vegetable consumption) to a healthy, traditional Mediterranean diet with low meat, and high fruit and vegetable consumption, resulted in 3-4 times higher insecticide and organophosphate exposure [141]. These results suggest that the effects of changing to organic food consumption, considering dietary pesticide intake and the associated potential negative health impacts, may be greater with a healthy diet.…”

“…There is also concern about the relatively high MRLs set by the EU for some widely used pesticides. For example, MRLs for chlormequat (7 mg kg −1 ) and glyphosate (10 mg kg −1 ) are more than 10 times higher than those set for most other pesticides (0.01-0.4 mg kg −1 ) licensed for use in Europe [141,161,201,202]. In this context, it is important to consider that both pesticides are suspected endocrine-disrupting chemicals [203] and glyphosate was recently classified as a probable carcinogen [204].…”