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Pesticides and the Mediterranean Style Diet

Whether one eats organic foods or non-organic foods does make  difference, even when eating a healthy Mediterranean style diet. A recent study found a difference is in the amount of pesticides ingested, with much less in the organic diet. Which makes sense.

A Mediterranean style diet emphasizes fruits, vegetables, whole grains, nuts, and legumes - thus lots of produce and fiber, much more than in a Western style diet. However, the study found that just 2 weeks of a Mediterranean diet with either organic foods or non-organic (conventional) foods made a huge difference in the amount of pesticides ingested. They measured this by looking at pesticide residues excreted in the urine.

In persons eating an all organic Mediterranean style diet 91% lower pesticide residues were excreted in the urine when compared to those eating a non-organic Mediterranean style diet! The study also showed that pesticide exposure actually increased in 1 group (the non-organic Mediterranean diet group) when compared to their normal non-organic (conventional) Western diet.

Participants (British postgraduate students, all adults) in a small study ate their normal Western diet (e.g., hamburgers, french fries) both before and after a 2 week period in which they ate a Mediterranean style diet (e.g., Greek salad, sweet and sour chicken, vegetables, and whole grain rice). During the Mediterranean style diet phase (the middle 2 weeks) all foods eaten by one group (13 persons) were organic, and in the second group (14 persons) they were all non-organic (conventional).

Other studies have also found similar findings (organic foods lowers pesticide levels in body), and lower incidence of cancer in those eating organic foods.

Bottom line: Yes, a Mediterranean style diet (whether non-organic or organic) is still considered healthiest for us all sorts of ways, including our gut microbiome. But.. try to eat as many organic foods as possible to lower exposure to all sorts of pesticides.

Excerpts from Beyond Pesticides: Unless You Go Organic, Switching to ‘Healthier’ Mediterranean Diet Increases Pesticide Exposure Three-fold

Replacing a modern, ‘western’ diet of highly processed foods with a Mediterranean diet filled with conventional, chemically-grown fruits and vegetables triples exposure to toxic pesticides, according to research recently published in The American Journal of Clinical Nutrition. However, this disturbing change can be eliminated by eating a Mediterranean diet consisting entirely of organic food, which is not sprayed with synthetic pesticides. 

The study found that switching from a ‘western’ to a Mediterranean diet increased pesticide levels in urine by three-fold. For organophosphate insecticides in particular, levels increased nearly 4x (from 7 to 25 μg/d). Between the organic and conventional Mediterranean diet, individuals that ate organic had 91% lower pesticide residue than those consuming foods only produced through conventional chemical farming practices. Researchers found that the primary source for pesticide residue came from chemically grown fruit, vegetables, and whole grain cereals. As the study authors note, such major disparities could have significant impacts on health.

The actual study from The American Journal of Clinical Nutrition: 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 than with conventional  food consumption. In the conventional group, switching from the habitual Western diet to the Mediterranean Diet 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 Mediterranean Diet 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.

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