More people are choosing organic food for a wide range of reasons. According to the Soil Association (2005) information sheet, organic milk generally contains higher levels of beneficial nutrients and vitamins than milk from non-organic cows.
Findings and Conclusions
The review concluded that organic milk contains higher levels of short-chain omega-3 essential fatty acids as well as vitamin E and the antioxidant beta-carotene. Higher levels of the antioxidants lutein and zeaxanthine have also been found on in milk from cows that eat grass-based diet typical of organic farming.
The compounds found in organic milk have a range of nutritional benefits including cancer and disease prevention. Soil Association (2005) reported the following from Ellis et al (2006) that organic milk had higher levels of polyunsaturated fatty acids through the year compared with non-organic milk. Average omega-3 fatty acids were 68% higher in organic milk. Organic milk contains a much lower omega-6:omega-3 fatty acid ratio, which is considered beneficial, than non-organic milk. The lower omega-3/omega-6 ratio is more desirable in reducing the risk of many chronic diseases of high prevalence in Western societies. No significant differences were found in conjugated linoleic acid (CLA) or vaccenic acid content.
Soil Association (2005) also reported that at a Danish Institute of Agricultural Sciences, studies have shown that organic milk in 7 out of 10 samples contained higher levels of vitamin E than non-organic milk and similarly, the beta-carotene content in organic milk was twice to thrice higher than non-organic milk (Nielsen & Lund-Nielsen, 2005). However, there was no difference in the fatty acid composition of the two milk types.
In Italy, Bergamo et al (2003) reported significantly higher essential fatty acids, including conjugated linoleic acid (CLA), linolenic acid (LNA) and vitamin E (alpha-tocopherol) in organic buffalo milk and mozzarella cheese obtained from farm dairies. Their study also found significantly higher levels of polyunsaturated fatty acids as well as fat-soluble vitamins and antioxidants (vitamin E and beta-carotene) in pasteurized and heat-treated organic cow’s milk and dairy products purchased from supermarkets. Organic cow milk contained 46% higher vitamin E, 60% beta-carotene and organic ricotta cheese contained 91% more CLA.
At the Institute of Grassland and Environmental Research, Aberystwyth, Dewhurst et al (2003) found that feeding clover silage, particularly red clover, increased the levels of polyunsaturated fatty acids which are beneficial for human health, particularly alpha-linolenic acid in milk according to the Soil Association (2005). A three-fold increase in milk alpha-linolenic acid levels was observed between cows offered red clover silage compared with grass silage. With cows fed with alfalfa and red clover silage, a significant reduction was observed in palmitic acid content of milk, which is known to increase plasma cholesterol in human.
Bergamo, P., Fedele, E., Iannibelli, L. & Marzillo, G. (2003). Fat-soluble vitamin contents and fatty acid composition in organic and conventional Italian dairy products. J. Food Chem. 82 (4):625-631.
Dewhurst, R. J., Fisher, W. J., Tweed, J. K. S. & Wilkins, R. J. (2003). Comparison of grass and legume silages for milk production. 1. Production responses with different levels of concentrate. Journal of dairy science 86:2598-2611.
Ellis, K., Innocent, G., Grove-White, D., Cripps, P., McLean, W. G., Howard, C. V. & Mihm, M. (2006). Comparing the fatty acid composition of organic and conventional milk. Journal of Dairy Science 89:1938-1950.
Nielsen, J. H. & Lund-Nielsen, T. (2005). Healthier organic livestock products; antioxidants in organic and conventional produced milk. Book of Abstract. First Annual Congress of the EU Project Quality Low Input Food and the Soil Association Annual Conference. Newcastle, 6-9 January, 2005.
Soil Association (2005). The nutritional benefits of organic milk – a review of the evidence. Soil Association Organic Standards. Revision 15. Soil Association, Bristol.