evidence-based blog of Filippo Dibari

Organic foods. Good for your health? We do not know, today. Maybe tomorrow…

In Under-nutrition on May 18, 2012 at 11:58 am

This morning, a friend of mine has solicited some insight about the relation between organic food and public health nutrition impact. I looked into the available systematic reviews from peer-reviewed journals. These are the results from the found studies – I could not find much more out there.

There are at least two ways to interpret these controversial papers* written by researchers from the London School of Hygiene and Tropical Medicine and other institutions, and whose abstracts are reported beneath.

  • The first interpretation is that “there is not sufficient evidence that eating organic may have a positive impact on human health“. Painful as it is, that is a matter of fact. However, there is more that can be learnt.
  • The second interpretation is that “the state of the art of the quality of research in the field of organic food and nutrition is (very?) poor“. Therefore, there is need not only for more research, but also with much higher quality standards.

Is there a third perspective about this topic? Other papers available?


* The papers retrieved are:

Nutrition-related health effects of organic foods: a systematic review

Alan D DangourKaren LockArabella HayterAndrea Aikenhead,Elizabeth Allen, and Ricardo Uauy

Am J Clin Nutr July 2010vol. 92 no. 1 203-210


Background: There is uncertainty over the nutrition-related benefits to health of consuming organic foods.

Objective: We sought to assess the strength of evidence that nutrition-related health benefits could be attributed to the consumption of foods produced under organic farming methods.

Design: We systematically searched PubMed, ISI Web of Science, CAB Abstracts, and Embase between 1 January 1958 and 15 September 2008 (and updated until 10 March 2010); contacted subject experts; and hand-searched bibliographies. We included peer-reviewed articles with English abstracts if they reported a comparison of health outcomes that resulted from consumption of or exposure to organic compared with conventionally produced foodstuffs.

Results: From a total of 98,727 articles, we identified 12 relevant studies. A variety of different study designs were used; there were 8 reports (67%) of human studies, including 6 clinical trials, 1 cohort study, and 1 cross-sectional study, and 4 reports (33%) of studies in animals or human cell lines or serum. The results of the largest study suggested an association of reported consumption of strictly organic dairy products with a reduced risk of eczema in infants, but the majority of the remaining studies showed no evidence of differences in nutrition-related health outcomes that result from exposure to organic or conventionally produced foodstuffs. Given the paucity of available data, the heterogeneity of study designs used, exposures tested, and health outcomes investigated, no quantitative meta-analysis was justified.

Conclusion: From a systematic review of the currently available published literature, evidence is lacking for nutrition-related health effects that result from the consumption of organically produced foodstuffs.

Nutritional quality of organic foods: a systematic review

Alan D Dangour,  Sakhi K Dodhia,  Arabella Hayter,  Elizabeth AllenKaren Lock, and Ricardo Uauy

Am J Clin Nutr September 2009 vol. 90 no. 3 680-685


Background: Despite growing consumer demand for organically produced foods, information based on a systematic review of their nutritional quality is lacking.

Objective: We sought to quantitatively assess the differences in reported nutrient content between organically and conventionally produced foodstuffs.

Design: We systematically searched PubMed, Web of Science, and CAB Abstracts for a period of 50 y from 1 January 1958 to 29 February 2008, contacted subject experts, and hand-searched bibliographies. We included peer-reviewed articles with English abstracts in the analysis if they reported nutrient content comparisons between organic and conventional foodstuffs. Two reviewers extracted study characteristics, quality, and data. The analyses were restricted to the most commonly reported nutrients.

Results: From a total of 52,471 articles, we identified 162 studies (137 crops and 25 livestock products); 55 were of satisfactory quality. In an analysis that included only satisfactory-quality studies, conventionally produced crops had a significantly higher content of nitrogen, and organically produced crops had a significantly higher content of phosphorus and higher titratable acidity. No evidence of a difference was detected for the remaining 8 of 11 crop nutrient categories analyzed. Analysis of the more limited database on livestock products found no evidence of a difference in nutrient content between organically and conventionally produced livestock products.

Conclusions: 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. The small differences in nutrient content detected are biologically plausible and mostly relate to differences in production methods.

A third paper tackles the topic more indirectly, but does not add much to the reported impact on the public health nutrition issue.

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