U.K. organic milk better for you than conventional, thanks to cows' grass-based diet
http://www.grist.org/article/food-2011-01-19-uk-study-organic-milk-has-healthier-fat-profile
http://download.journals.elsevierhealth.com/pdfs/journals/0022-0302/PIIS0022030210006703.pdf
According to an important new study, organic milk sold in England delivers significantly higher levels of healthy fatty acids than does conventional milk. The study, funded by the European Union and published in the peer-reviewed Journal of Dairy Science. The researchers compared fat composition and protein content of 10 organic and 12 conventional brands found on supermarket shelves in northeast England. Researchers found that the organic milk had only slightly higher overall fat content, but much higher levels of what it calls “beneficial fatty acids.”
http://www.grist.org/article/food-2011-01-19-uk-study-organic-milk-has-healthier-fat-profile
http://download.journals.elsevierhealth.com/pdfs/journals/0022-0302/PIIS0022030210006703.pdf
According to an important new study, organic milk sold in England delivers significantly higher levels of healthy fatty acids than does conventional milk. The study, funded by the European Union and published in the peer-reviewed Journal of Dairy Science. The researchers compared fat composition and protein content of 10 organic and 12 conventional brands found on supermarket shelves in northeast England. Researchers found that the organic milk had only slightly higher overall fat content, but much higher levels of what it calls “beneficial fatty acids.”
| The differences are significant in public-health terms. In America and Great Britain alike, people on average don’t get enough essential fatty acids. For example, one of the fatty acids in question, conjugated linoleic acid (CLA), has been shown to lower heart disease and cancer risks, the researchers say. The meat and milk of ruminant animals are “almost our exclusive source of dietary CLA,” the researchers support — and organic milk has significantly more of it. By switching to organic milk, the U.K. public could increase its average CLA intake by as much as 40 percent, the authors reckon. |  |
Conclusions
This survey of processed milk from different UK retail outlets confirms the results of raw milk surveys at the farm level, showing higher concentrations of nutritionally desirable fatty acids and n-3:n-6 ratios in milk from organic production systems. Although these differences at the retail level were significant for both summer and winter milk, the differential between production systems for all nutritionally desirable parameters does decrease in winter. To provide organic milk with similar fatty acid profiles throughout the year it is therefore important to develop strategies (e.g., oil seed supplementation of winter diets) that allow the seasonal differences in milk quality to be reduced. The finding of relatively large differences in milk composition between the sampling periods in this study suggests that differences in climatic conditions may influence milk quality through an effect on forage availability, quality, and intake. Because climate change predicts alternations in rainfall patterns and the frequency of “extreme weather events” (), both forage crop and dairy management practices may have to be adapted in the future to maintain current levels of product quality.
Abstract
This study of UK retail milk identified highly significant variations in fat composition. The survey, conducted over 2 yr replicating summer and winter, sampled 22 brands, 10 of which indicated organic production systems. Results corroborate earlier farm-based findings considering fat composition of milk produced under conventional and organic management. Organic milk had higher concentrations of beneficial fatty acids (FA) than conventional milk, including total polyunsaturated fatty acids (PUFA; 39.4 vs. 31.8 g/kg of total FA), conjugated linoleic acid cis-9,trans-11 (CLA9; 7.4 v 5.6 g/kg of FA), and α-linolenic acid (α-LN; 6.9 vs. 4.4 g/kg of FA). As expected, purchase season had a strong effect on fat composition: compared with milk purchased in winter, summer milk had a lower concentration of saturated fatty acids (682 vs. 725 g/kg of FA) and higher concentrations of PUFA (37.6 vs. 32.8 g/kg of FA), CLA9 (8.1 vs. 4.7 g/kg of FA), and α-LN (6.5 vs. 4.6 g/kg of FA). Differences identified between sampling years were more surprising: compared with that in yr 2, milk purchased in year 1 had higher concentrations of PUFA (37.5 vs. 32.9 g/kg of FA), α-LN (6.0 vs. 5.1 g/kg of FA), and linoleic acid (19.9 vs. 17.5 g/kg of FA) and lower concentrations of C16:0 and C14:0 (332 vs. 357 and 110 vs. 118 g/kg of FA, respectively). Strong interactions were identified between management and season as well as between season and year of the study. As in the earlier farm studies, differences in fat composition between systems were greater for summer compared with winter milk. Large between-year differences may be due to changes in weather influencing milk composition through forage availability, quality, and intake. If climate change predictions materialize, both forage and dairy management may have to adapt to maintain current milk quality. Considerable variation existed in milk fat composition between brands.
This survey of processed milk from different UK retail outlets confirms the results of raw milk surveys at the farm level, showing higher concentrations of nutritionally desirable fatty acids and n-3:n-6 ratios in milk from organic production systems. Although these differences at the retail level were significant for both summer and winter milk, the differential between production systems for all nutritionally desirable parameters does decrease in winter. To provide organic milk with similar fatty acid profiles throughout the year it is therefore important to develop strategies (e.g., oil seed supplementation of winter diets) that allow the seasonal differences in milk quality to be reduced. The finding of relatively large differences in milk composition between the sampling periods in this study suggests that differences in climatic conditions may influence milk quality through an effect on forage availability, quality, and intake. Because climate change predicts alternations in rainfall patterns and the frequency of “extreme weather events” (), both forage crop and dairy management practices may have to be adapted in the future to maintain current levels of product quality.
Abstract
This study of UK retail milk identified highly significant variations in fat composition. The survey, conducted over 2 yr replicating summer and winter, sampled 22 brands, 10 of which indicated organic production systems. Results corroborate earlier farm-based findings considering fat composition of milk produced under conventional and organic management. Organic milk had higher concentrations of beneficial fatty acids (FA) than conventional milk, including total polyunsaturated fatty acids (PUFA; 39.4 vs. 31.8 g/kg of total FA), conjugated linoleic acid cis-9,trans-11 (CLA9; 7.4 v 5.6 g/kg of FA), and α-linolenic acid (α-LN; 6.9 vs. 4.4 g/kg of FA). As expected, purchase season had a strong effect on fat composition: compared with milk purchased in winter, summer milk had a lower concentration of saturated fatty acids (682 vs. 725 g/kg of FA) and higher concentrations of PUFA (37.6 vs. 32.8 g/kg of FA), CLA9 (8.1 vs. 4.7 g/kg of FA), and α-LN (6.5 vs. 4.6 g/kg of FA). Differences identified between sampling years were more surprising: compared with that in yr 2, milk purchased in year 1 had higher concentrations of PUFA (37.5 vs. 32.9 g/kg of FA), α-LN (6.0 vs. 5.1 g/kg of FA), and linoleic acid (19.9 vs. 17.5 g/kg of FA) and lower concentrations of C16:0 and C14:0 (332 vs. 357 and 110 vs. 118 g/kg of FA, respectively). Strong interactions were identified between management and season as well as between season and year of the study. As in the earlier farm studies, differences in fat composition between systems were greater for summer compared with winter milk. Large between-year differences may be due to changes in weather influencing milk composition through forage availability, quality, and intake. If climate change predictions materialize, both forage and dairy management may have to adapt to maintain current milk quality. Considerable variation existed in milk fat composition between brands.
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