Organic Foods Key to Mediterranean Diet Health Benefits

New research reminds consumers that following a non-organic version of the Mediterranean diet leaves them exposed to pesticides and herbicides.
By Paolo DeAndreis
Nov. 17, 2021 11:57 UTC

The health ben­e­fits of fol­low­ing the Mediterranean diet are strictly related to the adop­tion of organic foods, accord­ing to new research pub­lished in the American Journal for Clinical Nutrition.

Our study demon­strates that con­sump­tion of organic foods allows con­sumers to change to a health­ier diet, with­out an increased intake of pes­ti­cides.- Per Ole Iversen, clin­i­cal nutri­tion pro­fes­sor, University of Oslo

Eating non-organ­i­cally grown foods asso­ci­ated with the Mediterranean diet exposes con­sumers to poten­tially harm­ful com­pounds from pes­ti­cides and her­bi­cides used on cer­tain crops.

Conversely, the researchers found that choos­ing organic options might lead to a 90-per­cent decrease in the con­sump­tion of tox­ins and pes­ti­cides.

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Twenty-seven British stu­dents were divided into two groups for five weeks dur­ing their stay in Crete, a south­ern Greek island and the country’s largest olive oil-pro­duc­ing region.

One group was given non-organic food from the Mediterranean diet, which involves eat­ing plenty of fruits, veg­eta­bles and whole grains. The other group received an organic ver­sion of the same diet. Previously, both groups of stu­dents had been mainly adher­ing to the tra­di­tional Western diet.

Researchers ana­lyzed both the food that was being eaten and the urine sam­ples col­lected from the stu­dents.

They found that high fruit and veg­etable con­sump­tion led to a three-times higher intake of insec­ti­cides and organophos­phate. Meanwhile, these val­ues were reduced by 90 per­cent in the group that fol­lowed the organic ver­sion of the diet.

More specif­i­cally, the research found that con­ven­tion­ally-grown fruits, veg­eta­bles and whole­grain cere­als might be the most sig­nif­i­cant dietary sources for syn­thetic chem­i­cal pes­ti­cides.

The sci­en­tists said that eat­ing organic food would reduce the total pes­ti­cide intake derived from eat­ing food com­pris­ing the tra­di­tional Mediterannean diet ten­fold.

To bet­ter under­stand what hap­pens when switch­ing from one type of diet to the other, the stu­dents con­sumed their reg­u­lar Western diet before and after the two-week inter­ven­tion period dur­ing which they switched to the Mediterranean diet.

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,” the researchers wrote. This may explain the pos­i­tive health out­comes linked to organic food con­sump­tion in obser­va­tional stud­ies.”

Per Ole Iversen, a pro­fes­sor of clin­i­cal nutri­tion at the University of Oslo, added that 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.”

Our study demon­strates that con­sump­tion of organic foods allows con­sumers to change to a health­ier diet, with­out an increased intake of pes­ti­cides,” he said.

According to the researchers, many syn­thetic pes­ti­cides detected in the urine sam­ples are con­firmed or sus­pected endocrine-dis­rupt­ing chem­i­cals, which cause can­cer.

See Also:Olives Among Foods with Lowest Level of Pesticide Residues in Europe, Study Finds

Therefore, the 10-times higher pes­ti­cide expo­sure from con­ven­tional foods may pro­vide a mech­a­nis­tic expla­na­tion for the lower inci­dence of obe­sity, meta­bolic syn­drome and can­cer asso­ci­ated with high lev­els of organic food con­sump­tion in epi­demi­o­log­i­cal and cohort stud­ies.

Carlo Leifert, a pro­fes­sor of plant sci­ence at Australia’s Southern Cross University and one of the lead researchers on the study, told Olive Oil Times that the most dan­ger­ous chem­i­cals found dur­ing the study are parathion and glyphosate.


Based on the World Health Organization and the International Agency for Cancer Research clas­si­fi­ca­tions for indi­vid­ual pes­ti­cides, the banned organophos­phate-insec­ti­cides parathion, with a WHO clas­si­fi­ca­tion as extremely haz­ardous, and the most widely-used pes­ti­cide glyphosate, with an IARC clas­si­fi­ca­tion as prob­a­bly car­cino­genic to humans, are the most dan­ger­ous sub­stances,” he said.

Leifert also empha­sized that the true extent of the dam­age caused by these chem­i­cals in humans is not fully under­stood and requires fur­ther research.

It is impor­tant to con­sider that humans are exposed to mix­tures of pes­ti­cides, and the dan­ger posed from mix­tures of pes­ti­cides is unknown,” he said.

According to Leifert, the most sig­nif­i­cant bar­rier to a major shift toward organic farm­ing is the depen­dency con­ven­tional farm­ing sys­tems have devel­oped regard­ing pes­ti­cide use.

It would take time and invest­ment, espe­cially in train­ing, to retrain farm­ers to use organic farm­ing meth­ods,” he said.

See Also:The Best Organic Olive Oils

Leifert indeed that in Western coun­tries, the aver­age age of farm­ers is around 60 years old, and near retire­ment age, farm­ers are reluc­tant to sub­stan­tially change the way they farm and take risks or make the invest­ments required to con­vert to organic pro­duc­tion.”

The most effec­tive ways to sup­port the phase-out of con­ven­tional farm­ing would be: tax­a­tion on agro­chem­i­cal inputs includ­ing pes­ti­cides and min­eral nitro­gen-fer­til­iz­ers, the man­u­fac­ture and appli­ca­tion of which is esti­mated to account for more than 20 per­cent of total green­house gas emis­sions from agri­cul­ture and on phos­pho­rous and potas­sium chlo­ride fer­til­iz­ers, which are both non-renew­able resources; invest­ment in organic train­ing at col­leges and uni­ver­sity level; research focused on the tech­ni­cal chal­lenges faced by organic farm­ers,” he added.

Leonidas Rempelos, the study’s co-author, added that the research might set a new path to eval­u­ate the true impact of intro­duc­ing new chem­i­cals in agri­cul­ture.

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,” he said. This study demon­strated the poten­tial of using organic food con­sumers as a low pes­ti­cide expo­sure con­trol group’ to inves­ti­gate the effect of cur­rently-used and newly-released pes­ti­cides on pub­lic health.”

Given the rel­e­vance of the research and the small scale of the cur­rent study, sci­en­tists told Olive Oil Times that they now hope to find the fund­ing to carry out a longer and larger human dietary inter­ven­tion study which inves­ti­gates the effect of chang­ing to organic food con­sump­tion on spe­cific health and health-related phys­i­o­log­i­cal para­me­ters.”

This would be designed to inves­ti­gate the mech­a­nisms for the health ben­e­fits asso­ci­ated with organic food con­sump­tion in the large human epi­demi­o­log­i­cal-cohort stud­ies car­ried out by Paris University-INRA in France, which were reviewed in our paper,” they con­cluded.


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