Organic Food No Better Nutritionally Than Conventionally Produced, Research Review
Scientists in the UK who systematically reviewed research from the last 50 years concluded that from a nutritional point of view, organically produced foods are no better than conventionally produced.
The study was the work of researchers from the London School of Hygiene and Tropical Medicine and appears in the 29 July issue of the American Journal of Clinical Nutrition.
Based on figures from 2007, the organic food industry is estimated to be worth 29 billion pounds (about 48 billion US dollars) worldwide and continues to grow while consumers appear willing to pay premium prices for food they believe to be superior in health and nutritional benefits.
Although some previous reviews have concluded that organic food is superior in nutritional content compared to conventionally produced food, nobody has yet done a systematic review of the literature, said a press statement from the London School of Hygiene and Tropical Medicine.
For this study, which was funded and commissioned by the UK Food Standards Agency (FSA), the authors sought to:
“Quantitatively assess the differences in reported nutrient content between organically and conventionally produced foodstuffs.”
They systematically searched abstracts databases for details of papers dating from the beginning of 1958 to the end of February 2008, contacted experts on the subject, and also manually searched bibliographies.
They included reports of research where the abstracts were written in English and the researchers had measured and compared the nutrient content of organic and conventional food.
To be of satisfactory quality and be included in the analysis, a study had to show it was designed with rigour. For instance, it had to include evidence of the organic certification scheme from which the studied foodstuffs were derived, the breed of livestock, the crop cultivar, plus details of lab methods and statistical tools used in the analysis.
The reviewers then analysed data on 13 nutrient categories.
They did not examine the content of contaminants or chemical residues.
The results showed that:
- From a total of over 52,000 articles, there were 162 (137 on crops and 25 on livestock products) that met the researchers’ first level of inclusion criteria but only 55 of these were of satisfactory quality and went into the analysis.
- Conventionally produced crops had a significantly higher content of nitrogen.
- Organically produced crops had a significantly higher content of phosphorus and higher titratable acidity.
- There was no evidence of a difference among the remaining 8 crop nutritient categories.
- Analysis of the few quality studies on livestock products showed no evidence of differences in nutritient content between those that were organically and those that were conventionally produced.
The researchers concluded that:
“On the basis of a systematic review of studies of satisfactory quality, there is no evidence of a difference in nutrient quality between organically and conventionally produced foodstuffs.”