Superiority of organic food thrown into doubt
By ALAN SAMSON
Claims that organically produced food has superior nutritional benefits to conventional food have been thrown into question by an Otago
The study, believed to be the first critical review of research comparing organic and conventional foods, and published by leading United States
journal Critical Reviews in Food Science and Nutrition, was commissioned by the Crop and Food Research Institute.
The review of about 100 international studies found no strong evidence that organic and conventional foods differed in concentrations of various
nutrients, with the possible exception of nitrate - found to be lower in some organic crops.
No evidence was found that certified organic foods might be more susceptible to microbiological contamination.
Also investigating taste, the study found no convincing evidence of any differences between conventional and organic produce. However, studies
had not clearly considered factors such as variety, time of harvest, distribution and storage conditions.
The principal researcher of Otago University's department of food science, Diane Bourn, said most of the studies that were looked at had been
poorly designed and did not control a large range of factors that could influence nutritional value.
Pursuing research that went beyond investigating basic nutrient levels was more difficult, but was an essential component in the evaluation of
organic production systems, she said.
People might still choose organics for other reasons, such as their containing no, or lower, pesticide residues, and environmental benefits such
as reduced fertiliser run-offs.
"It's possible that the non-use of pesticides in organic food production may lead to higher levels of compounds that help to naturally protect
plants against pests and diseases," Dr Bourn said. "Some of these may help protect against illnesses like heart disease and cancer. This is an
area where much more research needs to be carried out."
The study also found little data on pesticide residue in organic foods, "preventing definitive conclusions from being made about any differences
in the residue levels of organic and conventional".