British Journal of Nutrition

  • British Journal of Nutrition / Volume 115 / Issue 06 / March 2016, pp 1043-1060
  • Copyright © The Authors 2016 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.
  • DOI: (About DOI), Published online: 16 February 2016

Full Papers

Human and Clinical Nutrition

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-Tobera1a7, Marcin Barańskia1, Chris J. Seala2 id1, Roy Sandersona3, Charles Benbrooka4, Håvard Steinshamna5, Joanna Gromadzka-Ostrowskaa6, Ewa Rembiałkowskaa7, Krystyna Skwarło-Sońtaa8, Mick Eyrea1, Giulio Cozzia9, Mette Krogh Larsena10, Teresa Jordona1, Urs Nigglia11, Tomasz Sakowskia12, Philip C. Caldera13 id2, Graham C. Burdgea13, Smaragda Sotirakia14, Alexandros Stefanakisa14, Sokratis Stergiadisa1a15 id3, Halil Yolcua1a16, Eleni Chatzidimitrioua1, Gillian Butlera1, Gavin Stewarta1 and Carlo Leiferta1 c1

a1 Nafferton Ecological Farming Group (NEFG), School of Agriculture, Food and Rural Development, Newcastle University, Nafferton Farm, Stocksfield, Northumberland NE43 7XD, UK

a2 School of Agriculture, Food and Rural Development, Human Nutrition Research Centre, Newcastle University, Agriculture Building, Kings Road, Newcastle upon Tyne NE1 7RU, UK

a3 School of Biology, Newcastle University, Ridley Building, Newcastle upon Tyne NE1 7RU, UK

a4 Benbrook Consulting Services, 90063 Troy Road, Enterprise, OR 97828, USA

a5 Food and Agriculture Division-Grassland and Forage, Norwegian Institute of Bioeconomy Research (NIBIO), Gunnars veg 6, N-6630 Tingvoll, Norway

a6 Department of Dietetics, Faculty of Human Nutrition and Consumer Sciences, Warsaw University of Life Sciences, Nowoursynowska 159c, Warsaw 02-776, Poland

a7 Department of Functional and Organic Food and Commodities, Faculty of Human Nutrition and Consumer Sciences, Warsaw University of Life Sciences, Nowoursynowska 159c, Warsaw 02-776, Poland

a8 Department of Animal Physiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, Warsaw 02-096, Poland

a9 Department of Animal Medicine, Production and Health, University of Padua, Viale dell’ Università 19, 35020 Legnaro, Italy

a10 Department of Food Science-Food Chemistry & Technology, Aarhus University, Blichers Allé 20, Building F20/8845, 8830 Tjele, Denmark

a11 Research Institute for Organic Agriculture (FiBL), Ackerstrasse 113, CH-5070 Frick, Switzerland

a12 Institute of Genetics and Animal Breeding, Polish Academy of Science, Jastrzębiec, Postępu 36, Magdalenka 05-552, Poland

a13 Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK

a14 National Agricultural Research Foundation (NAGREF), Veterinary Research Institute of Thessaloniki, Thermi 57001, Thessaloniki, Greece

a15 School of Agriculture, Policy and Development, Centre for Dairy Research, Food Production and Quality Division, University of Reading, PO Box 237, Earley Gate, Reading RG6 6AR, UK

a16 Kelkit Aydin Vocational Training School, Gumushane University, 29600 Kelkit, Gumushane, Turkey





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.

(Received August 10 2015)

(Revised November 13 2015)

(Accepted January 08 2016)

Key words

  • Organic products;
  • Milk;
  • Dairy products;
  • Vitamins;
  • Antioxidants;
  • n-3 PUFA;
  • Conjugated linoleic acid


  • AA:arachidonic acid;
  • ALA: α-linolenic acid;
  • BS:basket studies;
  • CLA:conjugated linoleic acid;
  • EFSA:European Food Safety Authority;
  • EX:controlled experiments;
  • FA:fatty acid;
  • LA:linoleic acid;
  • MPD:mean percentage difference;
  • RDA:redundancy analysis;
  • SMD:standardised mean difference;
  • UM:unweighted meta-analysis;
  • VA:vaccenic acid;
  • VLC:very long chain;
  • WM:weighted meta-analysis


c1 Corresponding author: Professor C. Leifert, fax +44 1661 831 006, email