Many of us go off to the grocery store and willing spend much more money for organically grown food thinking that the nutritional value of this food will be better. A recent review of the literature calls this assumption into question. The study published July 29 in The American Journal of Clinical Nutrition says there is no evidence supporting this claim.

Many prior reviews have concluded that organically produced food has a superior nutrient composition to conventional food, but there has to-date been no systematic review of the available published literature.

Researchers from the London School of Hygiene & Tropical Medicine have completed an extensive review of the available published literature on nutrient content of organic food ever conducted. However, the review focused only on the nutritional content of the food, but did not evaluate the levels of contaminants or chemical residues in foods from different agricultural production regimens, an even more important concern for many consumers.

They evaluated over 50,000 papers and sorted out a total of 162 relevant articles that were published over a fifty-year period up to 29 February 2008 which compared the nutrient content of organically and conventionally produced foodstuffs. The researchers evaluated the quality of each article including information on the organic certification of the food from, the cultivar of crop or breed of livestock analyzed, the nutrient or other nutritionally relevant substance assessed, the laboratory analytical methods used, and the methods used for statistical analysis. They finally identified fifty five papers that met their rigorous standards. The final analysis was conducted comparing the content in organically and conventionally produced foods of the 13 most commonly reported nutrient categories.

They concluded that organically and conventionally grown foods were in fact comparable in their nutrient content. For 10 out of the 13 nutrient categories that they analyzed, they found no significant differences between production methods and nutrient content. The differences that were detected were were attributed to differences in fertilizer use (nitrogen, phosphorus), and ripeness at harvest (acidity), and it is unlikely that consuming these nutrients at the levels reported in organic foods would provide any health benefit.
As I pointed out earlier, this study did not look at the levels of toxic substances left on or in the flesh of the food nor did it evaluate the significant implications of residual antibiotics left in foodstuffs that are consumed.

The study was commissioned and funded by the UK Food Standards Agency. The funder had no role in study design, data collection, analysis, interpretation or writing of the report. The review team held six progress meetings with the funder.
Journal reference:
1. Alan D Dangour, Sakhi K Dodhia, Arabella Hayter, Elizabeth Allen, Karen Lock, Ricardo Uauy. Nutritional quality of organic foods: a systematic review. The American Journal of Clinical Nutrition, July 29, 2009 DOI: 10.3945/ajcn.2009.28041

Joel T Nowak MA, MSW