09
Nov
Unless You Go Organic, Switching to ‘Healthier’ Mediterranean Diet Increases Pesticide Exposure Three-fold
(Beyond Pesticides, November 9, 2021) 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 advantages of the Mediterranean diet, often ranked as the ‘best diet’ and emphasized by medical practitioners for its health benefits, now appear to depend on the production practices involved in the meals an individual eats. “There is growing evidence from observational studies that the health benefits of increasing fruit, vegetables and wholegrain consumption are partially diminished by the higher pesticide exposure associated with these foods,” said study coauthor Per Ole Iversen, MD. “Our study demonstrates that consumption of organic foods allows consumers to change to a healthier diet, without an increased intake of pesticides.”
Researchers began their investigation by establishing a randomized trial consisting of 27 adults, all of whom were postgraduate student volunteers on a study abroad course in Greece. The experiment lasted a total of five weeks, including a two-week intervention in the middle where the students’ ‘western’ food diet was switched for a defined Mediterranean diet. Before the intervention, students ate their normal ‘western’ diet, which included all conventional foods. For a typical ‘western’ diet, think burger and French fries, while researchers served for instance, a Greek salad, sweet and sour chicken and vegetables, and whole grain rice for the Mediterranean diet.
Researchers split the group in two (n=13 and n=14), with half receiving a Mediterranean diet with conventional foods, and the other half receiving organic foods. Participants kept food journals before, during, and after the intervention. Urine samples were taken over a 24h period and analyzed for pesticide residue. Scientists examined the foods provided to the student participants for 492 different pesticide active ingredients, and used these data to determine which pesticides would be tested in urine. The list includes plant growth regulators, synthetic herbicides like glyphosate, insecticides in the organophosphate, neonicotinoid, and pyrethroid class, and both synthetic and metal-based fungicides.
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.
“Many of the synthetic pesticides detected in both food and urine samples in this study are confirmed or suspected endocrine disrupting chemicals (EDC),” noted study co-author Carlo Leifert, PhD. “The 10 times higher pesticide exposure from conventional foods may therefore provide a mechanistic explanation for the lower incidence of overweight/obesity, metabolic syndrome and cancer associated with high levels of organic food consumption in epidemiological/cohort studies.”
The research is so convincing, it may be possible to base future public health research upon. “One of the difficulties of assessing the public health impacts of dietary exposure to pesticides is that once pesticides are widely used in food production everybody gets exposed,” said Leonidas Rempelos, PhD. “This study demonstrated the potential of using organic food consumers as a ‘low pesticide exposure control group’ to investigate the effect currently used and newly released pesticides on public health.”
Study after study have now found that eating organic lowers pesticide residue levels in one’s body. A 2015 study based on self-reported food intake found that those who eat organic generally have much lower levels of organophosphate insecticide metabolites in their urine. Additional research published in 2015 conducted an intervention study with children, finding that switching children to an organic diet decreased organophosphate metabolites in urine by 50% and 2,4-D by 25%. Research published in 2019 found that switching to organic reduced urine levels of certain organophosphates by up to 95%, and dropped neonicotinoid insecticide levels by 83%. A 2020 study found that switching to organic reduced glyphosate levels in the body by 70% over just a one week period.
Pesticide levels in urine have important implications for health. A 2013 study found that children with higher levels of pyrethroid insecticides in their urine were more likely to score high on reports of behavioral problems like inattention and hyperactivity. On the other hand, recent data indicate that children who eat higher amounts of organic food score higher on cognitive tests measuring fluid intelligence and working memory.
Coauthor of the current study, Chris Seal, PhD, says, “This study provides clear evidence that both our diet and the way we produce food may affect the level of exposure to synthetic chemical pesticides and ultimately our health.” While it is a common refrain among many well-intentioned health groups that one should eat more fruits and vegetables, no matter whether organic or conventional, the present study shows that this recommendation requires further scrutiny. Trading off one health risk for another becomes a dangerous game when organic options that effectively eliminate these risks exist.
Recent research shows that, at every level, organic outshines conventional practices. Organic farms spray fewer pesticides, and those that they use are significantly less toxic on an acute and chronic basis. Organic packaged foods offer greater health benefits over their conventionally processed counterparts. Environmental and socioeconomic systems are better served by organic practices, as research shows that organic provides quadruple aim performance, synergizing financial, human health, ecological, and socio-economic well-being.
For more information on why organic is the right path for the future of food, see Beyond Pesticides’ webpage on Organic Agriculture.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Newcastle University press release, The American Journal of Clinical Nutrition
