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Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses

  • Marcin Barański (a1), Dominika Średnicka-Tober (a1), Nikolaos Volakakis (a1), Chris Seal (a2), Roy Sanderson (a3), Gavin B. Stewart (a1), Charles Benbrook (a4), Bruno Biavati (a5), Emilia Markellou (a6), Charilaos Giotis (a7), Joanna Gromadzka-Ostrowska (a8), Ewa Rembiałkowska (a8), Krystyna Skwarło-Sońta (a9), Raija Tahvonen (a10), Dagmar Janovská (a11), Urs Niggli (a12), Philippe Nicot (a13) and Carlo Leifert (a1)...

Demand for organic foods is partially driven by consumers' perceptions that they are more nutritious. However, scientific opinion is divided on whether there are significant nutritional differences between organic and non-organic foods, and two recent reviews have concluded that there are no differences. In the present study, we carried out meta-analyses based on 343 peer-reviewed publications that indicate statistically significant and meaningful differences in composition between organic and non-organic crops/crop-based foods. Most importantly, the concentrations of a range of antioxidants such as polyphenolics were found to be substantially higher in organic crops/crop-based foods, with those of phenolic acids, flavanones, stilbenes, flavones, flavonols and anthocyanins being an estimated 19 (95 % CI 5, 33) %, 69 (95 % CI 13, 125) %, 28 (95 % CI 12, 44) %, 26 (95 % CI 3, 48) %, 50 (95 % CI 28, 72) % and 51 (95 % CI 17, 86) % higher, respectively. Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies. Additionally, the frequency of occurrence of pesticide residues was found to be four times higher in conventional crops, which also contained significantly higher concentrations of the toxic metal Cd. Significant differences were also detected for some other (e.g. minerals and vitamins) compounds. There is evidence that higher antioxidant concentrations and lower Cd concentrations are linked to specific agronomic practices (e.g. non-use of mineral N and P fertilisers, respectively) prescribed in organic farming systems. In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons.

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      Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses
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*Corresponding author: Professor C. Leifert, fax +44 1661 831 006, email
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2E Oughton & C Ritson (2007) Food consumers and organic agriculture. In Handbook of Organic Food Quality and Safety, pp. 7494 [J Cooper , U Niggli and C Leifert , editors]. Cambridge, UK: Woodhouse Publishing Ltd.

4 BPBaker , CMBenbrook , EGroth3rd , et al. (2002) Pesticide residues in conventional, integrated pest management (IPM)-grown and organic foods: insights from three US data sets. Food Addit Contam 19, 427446.

6AL Hansen (2010) The Organic Farming Manual: A Comprehensive Guide to Starting and Running a Certified Organic Farm. North Adams, MA: Storey Books.

7J Cooper , R Sanderson , I Cakmak , et al. (2011) Effect of organic and conventional crop rotation, fertilization, and crop protection practices on metal contents in wheat (Triticum aestivum). J Agric Food Chem 59, 47154724.

8ETL van Bueren , SS Jones , L Tamm , et al. (2011) The need to breed crop varieties suitable for organic farming, using wheat, tomato and broccoli as examples: a review. NJAS Wageningen J Life Sci 58, 193205.

9C Tetard-Jones , M Edwards , L Rempelos , et al. (2013) Effects of previous crop management, fertilization regime and water supply on potato tuber proteome and yield. Agronomy 3, 5985.

10L Rempelos , J Cooper , S Wilcockson , et al. (2013) Quantitative proteomics to study the response of potato to contrasting fertilisation regimes. Mol Breed 31, 363378.

11SJ Lehesranta , KM Koistinen , N Massat , et al. (2007) Effects of agricultural production systems and their components on protein profiles of potato tubers. Proteomics 7, 597604.

12C Tetard-Jones , PN Shotton , L Rempelos , et al. (2013) Quantitative proteomics to study the response of wheat to contrasting fertilisation regimes. Mol Breed 31, 379393.

13JP van Dijk , K Cankar , SJ Scheffer , et al. (2009) Transcriptome analysis of potato tubers – effects of different agricultural practices. J Agric Food Chem 57, 16121623.

14JP van Dijk , C Leifert , E Barros , et al. (2010) Gene expression profiling for food safety assessment: examples in potato and maize. Regul Toxicol Pharmacol 58, Suppl. 3, S21S25.

15JP van Dijk , K Cankar , PJM Hendriksen , et al. (2012) The identification and interpretation of differences in the transcriptomes of organically and conventionally grown potato tubers. J Agric Food Chem 60, 20902101.

16D Del Rio , A Rodriguez-Mateos , JPE Spencer , et al. (2013) Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases. Antioxid Redox Signal 18, 18181892.

19AD Dangour , SK Dodhia , A Hayter , et al. (2009) Nutritional quality of organic foods: a systematic review. Am J Clin Nutr 90, 680685.

20K Brandt , C Leifert , R Sanderson , et al. (2011) Agroecosystem management and nutritional quality of plant foods: the case of organic fruits and vegetables. Crit Rev Plant Sci 30, 177197.

21C Smith-Spangler , ML Brandeau , GE Hunter , et al. (2012) Are organic foods safer or healthier than conventional alternatives? A systematic review. Ann Intern Med 157, 348366.

23C Curl , RA Fenske & K Elgethun (2003) Organophosphorus pesticide exposure of urban and suburban preschool children with organic and conventional diets. Environ Health Perspect 111, 377382.

24C Leifert , K Ball , N Volakakis , et al. (2008) Control of enteric pathogens in ready-to-eat vegetable crops in organic and ‘low input’ production systems: a HACCP-based approach. J Appl Microbiol 105, 931950.

25G Stewart (2010) Meta-analysis in applied ecology. Biol Lett 6, 7881.

27K Brandt , D Srednicka-Tober , M Baranski , et al. (2013) Methods for comparing data across differently designed agronomic studies: examples of different meta-analysis methods used to compare relative composition of plant foods grown using organic or conventional production methods and a protocol for a systematic review. J Agric Food Chem 61, 71737180.

28G Stewart , I Cote , H Rothstein , et al. (2013) First steps in beginning a meta-analysis. In Handbook of Meta-Analysis in Ecology and Evolution, pp. 2736 [J Koricheva , J Gurevitch and K Mengersen , editors]. Princeton, NJ: Princeton University Press.

29E Palupi , A Jayanegara , A Ploeger , et al. (2012) Comparison of nutritional quality between conventional and organic dairy products: a meta-analysis. J Sci Food Agric 92, 27742781.

30Anonymous (2013) The R Project for Statistical Computing. (accessed 10 February 2013)..

31W Viechtbauer (2010) Conducting meta-analyses in R with the metafor package. J Stat Softw 36, 148.

32LV Hedges & I Olkin (1985) Statistical Methods for Meta-Analysis. San Diego, CA: Academic Press.

33J Sanchez-Meca & F Marin-Martinez (2010) Meta-analysis. In International Encyclopedia of Education, 3rd ed., pp. 274282 [P Peterson , E Baker and B McGaw , editors]. Amsterdam: Elsevier.

34MW Lipsey & DB Wilson (editors) (2001) Practical Meta-analysis. Thousand Oaks, CA: Sage Publications.

35LV Hedges , J Gurevitch & PS Curtis (1999) The meta-analysis of response ratios in experimental ecology. Ecology 80, 11501156.

, & () . : .37HR Rothstein AJ Sutton M Borenstein 2006 Publication Bias in Meta-Analysis Chichester, UKJohn Wiley & Sons Ltd

38J Gurevitch & LV Hedges (1999) Statistical issues in ecological meta-analyses. Ecology 80, 11421149.

41GH Guyatt , AD Oxman , GE Vist , et al. (2008) GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 336, 924926.

42L Grinder-Pedersen , SE Rasmussen , S Bügel , et al. (2003) Effect of diets based on foods from conventional versus organic production on intake and excretion of flavonoids and markers of antioxidative defense in humans. J Agric Food Chem 51, 56715676.

43M Søltoft , A Bysted , KH Madsen , et al. (2011) Effects of organic and conventional growth systems on the content of carotenoids in carrot roots, and on intake and plasma status of carotenoids in humans. J Sci Food Agric 91, 767775.

45C Lauridsen , C Yong , U Halekoh , et al. (2008) Rats show differences in some biomarkers of health when eating diets based on ingredients produced with three different cultivation strategies. J Sci Food Agric 88, 720732.

46D Srednicka-Tober , M Baranski , J Gromadzka-Ostrowska , et al. (2013) Effect of crop protection and fertilization regimes used in organic and conventional production systems on feed composition and physiological parameters in rats. J Agric Food Chem 61, 10171029.

47RL Nicholson & R Hammerschmidt (1992) Phenolic compounds and their role in disease resistance. Annu Rev Phytopathol 30, 369389.

48RN Bennett & RM Wallsgrove (1994) Secondary metabolites in plant defense mechanisms. New Phytol 127, 617633.

50JF Sander & R Heitefuss (1998) Susceptibility to Erysiphe graminis f. sp. tritici and phenolic acid content of wheat as influenced by different levels of nitrogen fertilization. J Phytopathol 146, 495507.

51S Rühmann , C Leser , M Bannert , et al. (2002) Relationship between growth, secondary metabolism, and resistance of apple. Plant Biol 4, 137143.

52AJ Stewart , W Chapman , GI Jenkins , et al. (2001) The effect of nitrogen and phosphorus deficiency on flavonol accumulation in plant tissues. Plant Cell Environ 24, 11891197.

54PK Bešter , F Lobnik , I Eržen , et al. (2013) Prediction of cadmium concentration in selected home-produced vegetables. Ecotoxicol Environ Saf 96, 182190.

57European Food Safety Authority (2011) The 2009 European Union report on pesticide residues in food. EFSA 9, 2430.

58M Marinovich , F Ghilardi & CL Galli (1996) Effect of pesticide mixtures on in vitro nervous cells: comparison with single pesticides. Toxicology 108, 201206.

59PA Pape-Lindstrom & MJ Lydy (1997) Synergistic toxicity of atrazine and organophosphate insecticides contravenes the response addition mixture model. Environ Toxicol Chem 16, 24152420.

60JC Axelrad , CV Howard & WG McLean (2002) Interactions between pesticides and components of pesticide formulations in an in vitro neurotoxicity test. Toxicology 173, 259268.

62P Bilsborrow , J Cooper , C Tetard-Jones , et al. (2013) The effect of organic and conventional crop production systems on the yield and quality of wheat (Triticum aestivum) grown in a long-term field trial. Eur J Agron 51, 7180.

66JO Lundberg , E Weitzberg & MT Gladwin (2008) The nitrate–nitrite–nitric oxide pathway in physiology and therapeutics. Nat Rev Drug Discov 7, 156167.

67A Machha & AN Schechter (2012) Inorganic nitrate: a major player in the cardiovascular health benefits of vegetables? Nutr Rev 70, 367372.

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