title: 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.
abstract: 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.
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Dominika
authors.initials: D
authors.lastname: Średnicka-Tober
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Marcin
authors.initials: M
authors.lastname: Barański
authors.affiliation: 2School of Agriculture, Food and Rural Development,Human Nutrition Research Centre,Newcastle University,Agriculture Building,Kings Road,Newcastle upon Tyne NE1 7RU,UK.
authors.forename: Chris J
authors.identifier: http://orcid.org/0000-0001-6313-6691
authors.initials: CJ
authors.lastname: Seal
authors.affiliation: 3School of Biology,Newcastle University,Ridley Building,Newcastle upon Tyne NE1 7RU,UK.
authors.forename: Roy
authors.initials: R
authors.lastname: Sanderson
authors.affiliation: 4Benbrook Consulting Services,90063 Troy Road, Enterprise,OR 97828,USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Benbrook
authors.affiliation: 5Food and Agriculture Division-Grassland and Forage,Norwegian Institute of Bioeconomy Research (NIBIO),Gunnars veg 6,N-6630 Tingvoll,Norway.
authors.forename: Håvard
authors.initials: H
authors.lastname: Steinshamn
authors.affiliation: 6Department of Dietetics, Faculty of Human Nutrition and Consumer Sciences,Warsaw University of Life Sciences,Nowoursynowska 159c,Warsaw 02-776,Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Gromadzka-Ostrowska
authors.affiliation: 7Department 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.
authors.forename: Ewa
authors.initials: E
authors.lastname: Rembiałkowska
authors.affiliation: 8Department of Animal Physiology, Faculty of Biology,University of Warsaw,Miecznikowa 1,Warsaw 02-096,Poland.
authors.forename: Krystyna
authors.initials: K
authors.lastname: Skwarło-Sońta
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Mick
authors.initials: M
authors.lastname: Eyre
authors.affiliation: 9Department of Animal Medicine, Production and Health,University of Padua,Viale dell' Università 19,35020 Legnaro,Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Cozzi
authors.affiliation: 10Department of Food Science-Food Chemistry & Technology,Aarhus University,Blichers Allé 20,Building F20/8845,8830 Tjele,Denmark.
authors.forename: Mette Krogh
authors.initials: MK
authors.lastname: Larsen
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Teresa
authors.initials: T
authors.lastname: Jordon
authors.affiliation: 11Research Institute for Organic Agriculture (FiBL),Ackerstrasse 113,CH-5070 Frick,Switzerland.
authors.forename: Urs
authors.initials: U
authors.lastname: Niggli
authors.affiliation: 12Institute of Genetics and Animal Breeding,Polish Academy of Science,Jastrzębiec, Postępu 36,Magdalenka 05-552,Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Sakowski
authors.affiliation: 13Human Development and Health Academic Unit, Faculty of Medicine,University of Southampton,Southampton SO16 6YD,UK.
authors.forename: Philip C
authors.identifier: http://orcid.org/0000-0002-6038-710X
authors.initials: PC
authors.lastname: Calder
authors.affiliation: 13Human Development and Health Academic Unit, Faculty of Medicine,University of Southampton,Southampton SO16 6YD,UK.
authors.forename: Graham C
authors.initials: GC
authors.lastname: Burdge
authors.affiliation: 14National Agricultural Research Foundation (NAGREF),Veterinary Research Institute of Thessaloniki,Thermi 57001,Thessaloniki,Greece.
authors.forename: Smaragda
authors.initials: S
authors.lastname: Sotiraki
authors.affiliation: 14National Agricultural Research Foundation (NAGREF),Veterinary Research Institute of Thessaloniki,Thermi 57001,Thessaloniki,Greece.
authors.forename: Alexandros
authors.initials: A
authors.lastname: Stefanakis
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Sokratis
authors.identifier: http://orcid.org/0000-0002-7293-182X
authors.initials: S
authors.lastname: Stergiadis
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Halil
authors.initials: H
authors.lastname: Yolcu
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Eleni
authors.initials: E
authors.lastname: Chatzidimitriou
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Gillian
authors.initials: G
authors.lastname: Butler
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Gavin
authors.initials: G
authors.lastname: Stewart
authors.affiliation: 1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
authors.forename: Carlo
authors.initials: C
authors.lastname: Leifert
mesh_terms: D000818:Animals; D002417:Cattle; D003612:Dairying; D004042:Dietary Fats, Unsaturated / Q000032:analysis*; D055317:Evidence-Based Practice; D015525:Fatty Acids, Omega-3 / Q000032:analysis*; D058870:Food, Organic / Q000032:analysis*; D006801:Humans; D007455:Iodine / Q000032:analysis; D019266:Iron, Dietary / Q000032:analysis*; D044243:Linoleic Acids, Conjugated / Q000032:analysis*; D058751:Livestock; D008892:Milk / Q000737:chemistry*; D009753:Nutritive Value; D012643:Selenium / Q000032:analysis; D024502:alpha-Tocopherol / Q000032:analysis*
chemical_list: D004042:Dietary Fats, Unsaturated; D015525:Fatty Acids, Omega-3; D019266:Iron, Dietary; D044243:Linoleic Acids, Conjugated; D007455:Iodine; D024502:alpha-Tocopherol; D012643:Selenium
keywords:     n-3 PUFA; AA arachidonic acid; ALA 
                    α-linolenic acid; Antioxidants; BS basket studies; CLA conjugated linoleic acid; Conjugated linoleic acid; Dairy products; EFSA European Food Safety Authority; EX controlled experiments; FA fatty acid; LA linoleic acid; MPD mean percentage difference; Milk; Organic products; RDA redundancy analysis; SMD standardised mean difference; UM unweighted meta-analysis; VA vaccenic acid; VLC very long chain; Vitamins; WM weighted meta-analysis