What is organic milk and does it confer any benefits compared to non-organic milk?

What is organic milk?

Milk that is labelled as organic has been certified to have been produced organically. This means that it has met the legislated standards for organic food production (European Commission, 2007). These standards aim to establish a sustainable management system for agriculture that:

·         Sustains and enhances the health of soil, water, plants and animals;

·         Contributes to a high level of biological diversity;

·         Makes responsible use of emergency and natural resources;

·         Respects high animal welfare standards;

·         Aims to produce ‘high quality’ products using processes that do not harm the environment, human health, plant health or animal health and welfare.

According to these rules, and with respect to organic milk production, cows must have plenty of space, access to pasture when the weather permits, and spend as much time outdoors as possible. There should be no routine use of antibiotics and de-wormers and cows must be fed a natural, grass-rich, organic diet.

Organic milk must carry the label of the government-approved body that it has been certified by (Box 1).

Box 1: Organic food labels

Nutritional differences between organic milk and non-organic milk

Although being labelled as ‘organic’ is no guarantee that milk will be more nutritious, studies have found differences in the nutritional content of organic milk compared to non-organic milk, as summarised below.

Fatty acids

A meta-analysis and systematic review of the results of 170 published studies (Srednicka-Tober, 2016) found that organic milk has significantly higher concentrations of total polyunsaturated fatty acids and beneficial omega-3 fatty acids than non-organic milk, by an estimated 7% and 56% respectively. Concentrations of long chain α-linolenic acid (ALA), very long-chain n-3 fatty acids (Eicosapentaenoic acid (EPA), Docosapentaenoic Acid (DPA) and Docosahexaenoic Acid (DHA)) and conjugated linoleic acid were also significantly higher in organic milk, by an estimated 69%, 57%, and 41% respectively. As there were no significant differences in total omega-6 fatty acids and linoleic acid (LA) concentrations (which it has been suggested are present in too high concentrations in Western diets), the n-6:n-3 and LA:ALA ratios were at lower levels in organic milk, by an estimated 71% and 93% respectively. On the basis of these results, the study concluded that organic milk has a more desirable fatty acid profile compared to non-organic milk, although intervention and cohort studies would be required to quantify any potential health impacts of switching to organic milk and dairy products (Srednicka-Tober, 2016).

It should be noted that the differences in fatty acid concentrations of organic and non-organic milk tend to be smaller in wintertime when cows in organic production systems are housed (Butler, 2008) and may also be affected by climatic conditions in different geographic areas (Stergiadis, 2012). However, even taking these variations into account, organic milk still has a more desirable fatty acid profile compared to non-organic milk (Butler and Stergiadis, 2020).

There is strong evidence to show that the improved fatty acid profile of organic milk is the result of organic farms relying more heavily on pasture and forage-based feeds, rather than imported grain-based feeds (Srednicka-Tober, 2016; Benbrook, 2013; Butler, 2011). The same, or in some cases greater, benefits in respect of the fatty acid profiles may therefore be found in milk produced from pasture-fed cows (Box 1), whether organic or not. 

 Box 2:  Pasture-fed cows

Micronutrients

In addition to the preferable fatty acid profile of organic milk compared to non-organic milk, the same meta-analysis of 170 studies showed that organic milk has an estimated 13% higher concentration of α-tocopherol (a form of vitamin E) and 20% higher iron, but a 74% lower level of iodine and 21% lower level of selenium (Srednicka-Tober, 2016).

The much lower level of iodine in organic milk may appear concerning given that iodine is essential for brain development, particularly in early pregnancy, and because milk is the main source of dietary iodine in the UK. However, while milk contributes an estimated 47% of the iodine intakes of children aged 1.5-3 years, it provides 85% of the recommended nutrient intake for iodine (PHE, 2020). Milk and milk products together contribute an estimated 64% of the iodine intakes of children aged 1.5-3 years, contributing even more to the RNI (see our briefing note on Animal milks in the diets of 1-4 year olds here). Whether organic or pasture-fed milk and milk products or non-organic milk and milk products are chosen for children aged 1-4 years old, these should be consumed as part of a healthy, well balanced diet that includes foods that are rich in iodine, such as fish and shellfish.

Agricultural contaminants in organic and non-organic milk  

Contaminants may find their way into milk indirectly through residues of pesticides on cow feed, or as residues of veterinary drugs such as antibiotics. Evidence shows that with sufficient exposure, pesticides can contribute to delayed motor and neurological development in children (Welsh, 2019). The use of growth hormones is not permitted in the UK meaning these are not contaminants of concern.

Organic production regulations greatly limit the number of pesticides that can be used, how often and how they are used. In addition, organic production regulations stipulate that artificial fertilisers cannot be used in cow feed, and there can be no routine use of antibiotics.

However, despite more stringent controls in organic production systems, routine surveillance suggests that pesticide residues are typically absent from both organic and non-organic milk in the UK (DEFRA, 2021) added to which there are limits on antibiotic residues in all cows’ milk.

Sustainability of organic compared to non-organic milk

It is claimed that organic milk is better for the planet, wildlife and animal welfare (Soil Association, 2021).

A systematic review of 179 studies across multiple countries compared organic and non-organic livestock production systems for their sustainability (Van Wagenberg, 2017). Results showed that, compared to non-organic systems, organic systems had lower water eutrophication (water becoming full of excessive nutrients), and lower acidification (soil becoming more acidic) per unit of land. However, as organic systems were less productive than non-organic systems, acidification and eutrophication were higher per unit of product compared to non-organic systems. Conversely, organic systems had a lower negative impact on biodiversity, explained by the absence of pesticides and synthetic fertilisers, a lower stocking rate per unit of land, and a better balance between cutting, grazing and external inputs.

A total of 12 of the 179 studies reviewed assessed the impact of organic farming on climate change (Van Wagenberg, 2017). Results showed that the global warming potential (GWP) of organic and non-organic systems was the same, given that organic systems had higher enteric methane emission per unit of milk (due to the lower milk yield per cow and increased use of roughage), but lower emissions of CO2 and nitrous oxide when compared to non-organic systems. However, a study by Trydeman Knudsen (2019) found that when soil carbon changes are included in such analyses, the GWP of organic milk production came out 5-18% lower given that increased pasture feeding of cows leads to increased soil carbon sequestration. The same benefits may also in theory be applied to pasture-fed production, whether organic or not (Box 1).

In terms of animal welfare, a recent systematic review of 166 studies of animal health and welfare in organic versus non-organic production systems (Akerfeldt, 2021) found some evidence of positive effects on livestock behaviour in organic compared to non-organic systems, due to factors such as larger areas for grazing and longer outdoor periods. However, judged on the basis of a narrow set of metrics, this study reported no evidence of an effect on animal health and welfare, which were the same in organic and non-organic systems. Despite this finding it is relevant to note that compared with normal industry practice, organic standards offer many potential welfare advantages in addition to those factors outlined above, including: prohibition of tethering; prohibition of fully-slatted floors; provision of adequate bedding, shelter and shade; prohibition of electric goads; a restriction on transport duration to eight hours and prohibition of the live export of calves under one month old and of cows for slaughter; and specifications and monitoring to ensure effective pre-slaughter stunning and unconsciousness until death (CIWF and OneKind, 2012).

To summarise, the evidence we could find suggests that organic production systems are probably more sustainable and better for the environment than non-organic systems. Added to this, organic standards deliver a range of potential welfare benefits, though more research is needed to thoroughly understand how these translate consistently into health and welfare outcomes.

Cost of organic milk compared to non-organic milk

The below cost comparison between two pint cartons of semi-skimmed milk available from leading UK supermarkets (undertaken in August 2021) indicates that across these brands, the average price for two pints of non-organic milk was 73p, compared to an average price of the same volume of organic milk of 97.4p. Organic milk was between 21p and 31p more expensive within the same brand. Across the brands, on average, two pints of organic milk was 24.4p, or one third more expensive than non-organic milk. For a child consuming 350ml of milk a day over a year, the excess cost for purchasing organic milk over non-organic milk using these prices would therefore be about £28.

Conclusion

Organic milk is more expensive than non-organic milk, however it is likely more sustainable and better for the environment than non-organic milk and to confer some welfare advantages to the cows involved. In addition, organic milk has a more desirable fatty acid profile compared to non-organic milk, as well as higher levels of some micronutrients, but lower levels of iodine, and to a lesser extent, selenium. The same nutritional differences are likely to be seen in pasture-fed milk. Whether organic or pasture-fed milk and milk products, or non-organic milk and milk products are chosen for children aged 1-4 years old, these should be consumed as part of a healthy, well balanced diet that includes foods that are rich in iodine, such as fish and shellfish.

References 

Åkerfeldt, M.P., Gunnarsson, S., Bernes, G. et al. (2021). Health and welfare in organic livestock production systems—a systematic mapping of current knowledge. Org. Agr. 11, 105–132. https://doi.org/10.1007/s13165-020-00334-y

Benbrook, C.M., Butler, G., Latif, M.A., et al. (2013). Organic Production Enhances Milk Nutritional Quality by Shifting Fatty Acid Composition: A United States–Wide, 18-Month Study. PLoS ONE 8(12): e82429. https://doi.org/10.1371/journal.pone.0082429

Butler, G., Nielsen, J.H., Slots, T. et al. (2008). Fatty acid and fat-soluble antioxidant concentrations in milk from high- and low-input non-organic and organic systems: seasonal variation. J. Sci. Food Agric., 88, 1431-1441. https://doi.org/10.1002/jsfa.3235

Butler, G., Nielsen, J.H., Larsen, B. et al. (2011). The effects of dairy management and processing on quality characteristics of milk and dairy products, NJAS - Wageningen Journal of Life Sciences, 58, (3–4),  97-102, ISSN 1573-5214, https://doi.org/10.1016/j.njas.2011.04.002 

Butler, G. and Stergiadis, S. (2020). Chapter 5 - Organic milk: Does it confer health benefits?, Editor(s): D. Ian Givens, Milk and Dairy Foods, Academic Press, 2020, https://doi.org/10.1016/B978-0-12-815603-2.00005-X.

Compassion in World Farming and One Kind (2012). Farm assurance schemes and animal welfare: How the standards compare. https://www.ciwf.org.uk/media/5231255/standards_analysis_main_report.pdf

Davis, H., Chatzidimitriou, E., Leifert, C., and Butler, G. (2020). Evidence That Forage-Fed Cows Can Enhance Milk Quality. Sustainability  12, (9), 3688. https://doi.org/10.3390/su12093688

DEFRA (2021) Pesticide residues in food: quarterly monitoring results for 2021https://www.gov.uk/government/publications/pesticide-residues-in-food-quarterly-monitoring-results-for-2021 (accessed 15/02/2022)

European Commission (2007). Council Regulation (EC) No 834/2007 of 28 June 2007 on organic production and labelling of organic products. https://www.legislation.gov.uk/eur/2007/834/contents# (accessed 27/08/2021)

Soil Association (2021). https://www.soilassociation.org/ (accessed 27/08/2021)

Średnicka-Tober, D., Barański, M., Seal, C., et al. (2016). 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. British Journal of Nutrition, 115, (6), 1043-1060. doi:10.1017/S0007114516000349

Stergiadis, S., Leifert, C., Seal, C.J., et al. (2012). Effect of feeding intensity and milking system on nutritionally relevant milk components in dairy farming systems in the North East of England. J. Agric. Food Chem.  60, (29), 7270–7281 https://doi.org/10.1021/jf301053b 

Knudsen, M,T., Dorca-Preda, T., Djomo, S,N,. et al.  (2019). The importance of including soil carbon changes, ecotoxicity and biodiversity impacts in environmental life cycle assessments of organic and non-organic milk in Western Europe, Journal of Cleaner Production, 215, 433-443, ISSN 0959-6526, https://doi.org/10.1016/j.jclepro.2018.12.273.

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Van Wagenberg, C., De Haas, Y., Hogeveen, H., et al. (2017). Animal Board Invited Review: Comparing conventional and organic livestock production systems on different aspects of sustainability. Animal, 11, (10), 1839-1851. doi:10.1017/S175173111700115X

Welsh, J.A., Braun, H., Brown, N., et al. (2019). Production-related contaminants (pesticides, antibiotics and hormones) in organic and conventionally produced milk samples sold in the USA. Public Health Nutr. 22, (16), 2972-2980. doi: 10.1017/S136898001900106X