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Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses

  • Dominika Średnicka-Tober (a1) (a2), Marcin Barański (a1), Chris J. Seal (a3), Roy Sanderson (a4), Charles Benbrook (a5), Håvard Steinshamn (a6), Joanna Gromadzka-Ostrowska (a7), Ewa Rembiałkowska (a2), Krystyna Skwarło-Sońta (a8), Mick Eyre (a1), Giulio Cozzi (a9), Mette Krogh Larsen (a10), Teresa Jordon (a1), Urs Niggli (a11), Tomasz Sakowski (a12), Philip C. Calder (a13), Graham C. Burdge (a13), Smaragda Sotiraki (a14), Alexandros Stefanakis (a14), Sokratis Stergiadis (a1) (a15), Halil Yolcu (a1) (a16), Eleni Chatzidimitriou (a1), Gillian Butler (a1), Gavin Stewart (a1) and Carlo Leifert (a1)...

Demand for organic milk is partially driven by consumer perceptions that it is more nutritious. However, there is still considerable uncertainty over whether the use of organic production standards affects milk quality. Here we report results of meta-analyses based on 170 published studies comparing the nutrient content of organic and conventional bovine milk. There were no significant differences in total SFA and MUFA concentrations between organic and conventional milk. However, concentrations of total PUFA and n-3 PUFA were significantly higher in organic milk, by an estimated 7 (95 % CI −1, 15) % and 56 (95 % CI 38, 74) %, respectively. Concentrations of α-linolenic acid (ALA), very long-chain n-3 fatty acids (EPA+DPA+DHA) and conjugated linoleic acid were also significantly higher in organic milk, by an 69 (95 % CI 53, 84) %, 57 (95 % CI 27, 87) % and 41 (95 % CI 14, 68) %, respectively. As there were no significant differences in total n-6 PUFA and linoleic acid (LA) concentrations, the n-6:n-3 and LA:ALA ratios were lower in organic milk, by an estimated 71 (95 % CI −122, −20) % and 93 (95 % CI −116, −70) %. It is concluded that organic bovine milk has a more desirable fatty acid composition than conventional milk. Meta-analyses also showed that organic milk has significantly higher α-tocopherol and Fe, but lower I and Se concentrations. Redundancy analysis of data from a large cross-European milk quality survey indicates that the higher grazing/conserved forage intakes in organic systems were the main reason for milk composition differences.

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      Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses
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This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Corresponding author
* Corresponding author: Professor C. Leifert, fax +44 1661 831 006, email
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