12:13PM Thursday Jul 30, 2009
By Martin Hickman
Scientists at the London School of Hygiene and Tropical Medicine have found there is no significant nutritional difference between organic and non-organic produce. Photo / Bay of Plenty Times
Organic food is no healthier than conventional produce, shows a comprehensive review of 50 years of evidence.
Scientists at the London School of Hygiene and Tropical Medicine spent 12 months reviewing nutritional research on foodstuffs produced normally and under organic standards which ban artificial fertilisers and other chemicals.
Which? said the conclusion that there is no significant nutritional difference between the two systems could prompt shoppers to think twice about buying organic food. But organic farming experts questioned why the study dismissed evidence from some papers.
Funded by the Food Standards Agency, researchers searched scientific journals for all reviews of organic and non-organic fruit, vegetables, meat and dairy between 1958 and February 2008.
Of 162 relevant studies, they deemed 55 to be of "satisfactory quality".
They found no significant difference between organic and non-organic farming for 20 of 23 nutritional categories including vitamin C and iron.
Organic food had higher levels of phosphorous and acidity and conventional food was higher in nitrates. When all 162 papers were considered, organic farming was higher in 11 nutrients.
Dr Alan Dangour, who led the study, said: "A small number of differences in nutrient content were found to exist between organically and conventionally-produced crops and livestock, but these are unlikely to be of public health relevance. We found, broadly, that there was no important difference between organic and conventional produce."
The FSA stressed that while it was neither for nor against organic food, it considered that the long-running health debate was over.
"This study does not mean we should not eat organic food," said Gill Fine, its director of dietary health.
"What it shows is that... there is no evidence of additional health benefits from eating organic food."
The findings accord with the FSA's previous advice and echo the views of government ministers that eating organic food is a "lifestyle" rather than a nutritional choice.
Peter Melchett, policy director of the organic certifier the Soil Association, said raw data showed some nutrients were far higher in organic food, such beta carotenes, 53 per cent higher and flavanoids, up 38 per cent.
He added: "The review rejected almost all of the existing studies of comparisons between organic and non-organic nutritional differences. This was because these studies did not meet particular criteria fixed by the London School of Hygiene and Tropical Medicine."
The independent research did not consider a £12m, four-year study by Carlo Leifert, professor of ecology at Newcastle University.