Are organic foods healthier?

By Amanda Johnson 07/09/2012

A new systematic review published in the Annals of Internal Medicine this week suggests not.

The authors of this latest research reviewed 17 human studies and 223 studies of nutrient and contaminant levels. They conclude that the published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods; although consumption of organic foods may reduce exposure to pesticide residues and antibiotic resistant bacteria.

So what is the difference between organic and conventionally produced food? Well, according to the NZFSA, organic agriculture is “a production system that avoids or largely excludes the use of synthetic fertilisers, pesticides, growth regulators and feed additives.”  

They go on to say that, “organic agricultural practices are premised on a philosophy of farming articulated through four basic principals – health, ecology, fairness and care. For consumers who purchase organic foods often health, taste and environmental benefits are important considerations in their food choice.”

This latest review paper found that organic produce had a 30% lower risk for contamination with any detectible pesticide residue than conventional produce. However, in New Zealand, the Ministry for Primary Industries state,

“The use of pesticides, herbicides, fertilisers, and veterinary medicines is strictly regulated in New Zealand, such that any residues present in food due to the use of these agricultural compounds are at levels that present notional zero risk to consumers. The term ‘notional zero risk’ is used to describe the risk associated with consuming levels of substances below the acceptable daily intake (ADI) which is the level at which a substance can be consumed every day for a whole lifetime without noticeable effect.”

From a nutritional perspective this latest review paper showed there is little difference between organic and conventionally produced food. There were no significant differences in vitamin content, and although phosphorous and total phenol content of organic foods were higher, the difference was of little clinical significance.

Organic produce can be considerably more expensive and the authors of this latest research conclude that despite the widespread perception that organically produced foods are more nutritious than conventional alternatives, they did not find any robust evidence to support this perception.

For anyone concerned about pesticide residues, consumption of conventionally produced fruits and vegetables has not been found to pose any risk to health – but washing and peeling fruits and vegetables will reduce exposure. For more information check out this Cancer Society information sheet.

The benefits of consuming fruits and vegetables certainly outweigh any risk, and we should all be consuming at least five portions a day of this important food group