News, Culture & Society

Food: Traditionally-grown Mediterranean fare can TRIPLE pesticide intake compared to Western diet

The not-so-healthy Mediterranean diet? Switching from ‘Western’ foods to non-organically-grown fruit, veg and whole grains can TRIPLE the pesticides you consume and weaken your immune system, study warns

  • University of Oslo-led experts studied different diets among 27 UK students
  • Non-organically grown produce picks up more environmental contaminants 
  • A regular Mediterranean diet was found worse in this regard than ‘British’ fare
  • However, farming the same Mediterranean produce organically was better 
  • It cut pesticide levels by 90% compared to non-organic Mediterranean food

Switching from ‘Western’ foods to a non-organically-cultivated Mediterranean diet may triple your pesticide intake and weaken the immune system.

This is the conclusion of a study led by researchers from the University of Oslo, who compared the effects of different diets on a group of 27 British students.

The team found that produce farmed in the traditional manner passed on more environmental contaminants, which may affect fertility and juvenile development. 

Rich in fruit, vegetables, whole grains, nuts and fish but low in red meat and dairy, the Mediterranean diet has long been hailed as a healthy alternative to British fare.

While the fish part of the diet is low in environmental contaminants, non-organic farming of fruit, veg and whole grains passes on more pesticides.

However, the team noted, when the ingredients of the Mediterranean diet are farmed organically, such can slash pesticide intake by around 90 per cent.

Switching from organically-grown ‘Western’ foods to a conventionally-cultivated Mediterranean diet may triple your pesticide intake and weaken the immune system


It is important to wash fruit and vegetables in water before eating them to remove any residue pesticides that are used to control pests and can be detrimental to human health.

Produce is also at a high risk of contamination from dust, dirt and bacteria as most is stored in warehouses, before travelling in containers and being stored again at retailers.

Failure to wash fruit and vegetables can cause food poisoning, such as an E.coli infection. 

It is particularly important to wash off any soil as this is usually where bacteria resides.

NHS Choices advises people wash fruits and vegetables under running tap water.

The Food Standards Agency also recommends people wash produce before use but adds this will not completely eliminate potentially-harmful residues, only lessen those on the surface.

Peeling can be a more effective method, however, this removes fibre and important nutrients, such as vitamin C. 

Friends of the Earth claims the best way to avoid pesticides in produce is to eat organic fruit and vegetables.

Several of the environmental contaminants seen in the study are either known or suspected to affect hormones within the body, noted paper author and microbiologist Carlo Leifert, who is a visiting professor at the University of Oslo.

‘There is growing evidence that such toxins can weaken our immune defence system and perhaps also our fertility,’ he explained.

‘If hormones become imbalanced, they can also have a negative effect on the growth and development of children.

‘Fruits, vegetables and whole grains cultivated in the conventional way are some of the main sources of environmental contaminants absorbed through our diet.

‘Since a Mediterranean diet is based on such foods, those eating it have a ten times higher intake of these contaminants than if their diet had been based on foods cultivated organically.’

‘Both farmed and wild fish can contain environmental contaminants, but usually in small quantities,’ Professor Leifert continued.

In their study, the team recruited 27 students who first consumed ‘ordinary’ British food for a week, logging everything that they ate.

The researchers then took a urine sample from them before shipping them off to a farm in Crete for two weeks. While there, 14 ate a diet of food cultivated traditionally, while the other 13 ate a diet comprised of organic produce.

Each participant’s urine was then tested again for contaminants like those derived from fertiliser usage before they returned home to spend another week on their normal British diet.

‘The group consuming a Mediterranean diet based on conventionally produced food were shown to have three times the level of environmental contaminants in their urine compared to when they were eating their normal, Western diet,’ Professor Leifert said.

Professor Leifert and his colleagues warned, however, that it is too early for health chiefs to start recommending against a Mediterranean diet based around non-organically grown produce.

With only a small study cohort, more research is needed, they explained.

Alongside this, environmental contaminants also enter our bodies from other sources such as skin creams and even the air we breathe.

The study was published in the American Journal of Critical Nutrition.


At the core of the Mediterranean diet is the consumption of more fruit and fish, and fewer sugary drinks and snacks.

The diet places an emphasis on:

  • Fruits
  • Vegetables
  • Legumes
  • Nuts
  • Seeds
  • Whole grains
  • Fish and meat
  • Monounsaturated fats, such as olive oil

Followers of the diet should each less:

  • Saturated fats, like butter
  • Red meat
  • Processed foods, like juice and white bread
  • Soda
  • Sugar

However, in moderation, a glass of red wine here and there is fine.

How you can follow the Mediterranean diet:

  • Eat more fish
  • Squeeze more fruit & veg into every meal
  • Swap your sunflower oil or butter for extra virgin olive oil
  • Snack on nuts
  • Eat fruit for dessert