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Br J Nutr. 2016 Mar 28;115(6):1043-60. doi: 10.1017/S0007114516000349. Epub 2016 Feb 16.

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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1Nafferton Ecological Farming Group (NEFG),School of Agriculture, Food and Rural Development,Newcastle University,Nafferton Farm,Stocksfield,Northumberland NE43 7XD,UK.
2School of Agriculture, Food and Rural Development,Human Nutrition Research Centre,Newcastle University,Agriculture Building,Kings Road,Newcastle upon Tyne NE1 7RU,UK.
3School of Biology,Newcastle University,Ridley Building,Newcastle upon Tyne NE1 7RU,UK.
4Benbrook Consulting Services,90063 Troy Road, Enterprise,OR 97828,USA.
5Food and Agriculture Division-Grassland and Forage,Norwegian Institute of Bioeconomy Research (NIBIO),Gunnars veg 6,N-6630 Tingvoll,Norway.
6Department of Dietetics, Faculty of Human Nutrition and Consumer Sciences,Warsaw University of Life Sciences,Nowoursynowska 159c,Warsaw 02-776,Poland.
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.
8Department of Animal Physiology, Faculty of Biology,University of Warsaw,Miecznikowa 1,Warsaw 02-096,Poland.
9Department of Animal Medicine, Production and Health,University of Padua,Viale dell' Università 19,35020 Legnaro,Italy.
10Department of Food Science-Food Chemistry & Technology,Aarhus University,Blichers Allé 20,Building F20/8845,8830 Tjele,Denmark.
11Research Institute for Organic Agriculture (FiBL),Ackerstrasse 113,CH-5070 Frick,Switzerland.
12Institute of Genetics and Animal Breeding,Polish Academy of Science,Jastrzębiec, Postępu 36,Magdalenka 05-552,Poland.
13Human Development and Health Academic Unit, Faculty of Medicine,University of Southampton,Southampton SO16 6YD,UK.
14National Agricultural Research Foundation (NAGREF),Veterinary Research Institute of Thessaloniki,Thermi 57001,Thessaloniki,Greece.


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.


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

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