Organic Production Enhances Milk Nutritional Quality by Shifting Fatty Acid Composition: A United States–Wide, 18-Month Study

Indiana University, United States of America
PLoS ONE (Impact Factor: 3.23). 12/2013; 8(12):e82429. DOI: 10.1371/journal.pone.0082429
Source: PubMed


Over the last century, intakes of omega-6 (ω-6) fatty acids in Western diets have dramatically increased, while omega-3 (ω-3) intakes have fallen. Resulting ω-6/ω-3 intake ratios have risen to nutritionally undesirable levels, generally 10 to 15, compared to a possible optimal ratio near 2.3. We report results of the first large-scale, nationwide study of fatty acids in U.S. organic and conventional milk. Averaged over 12 months, organic milk contained 25% less ω-6 fatty acids and 62% more ω-3 fatty acids than conventional milk, yielding a 2.5-fold higher ω-6/ω-3 ratio in conventional compared to organic milk (5.77 vs. 2.28). All individual ω-3 fatty acid concentrations were higher in organic milk-α-linolenic acid (by 60%), eicosapentaenoic acid (32%), and docosapentaenoic acid (19%)-as was the concentration of conjugated linoleic acid (18%). We report mostly moderate regional and seasonal variability in milk fatty acid profiles. Hypothetical diets of adult women were modeled to assess milk fatty-acid-driven differences in overall dietary ω-6/ω-3 ratios. Diets varied according to three choices: high instead of moderate dairy consumption; organic vs. conventional dairy products; and reduced vs. typical consumption of ω-6 fatty acids. The three choices together would decrease the ω-6/ω-3 ratio among adult women by ∼80% of the total decrease needed to reach a target ratio of 2.3, with relative impact "switch to low ω-6 foods" > "switch to organic dairy products" ≈ "increase consumption of conventional dairy products." Based on recommended servings of dairy products and seafoods, dairy products supply far more α-linolenic acid than seafoods, about one-third as much eicosapentaenoic acid, and slightly more docosapentaenoic acid, but negligible docosahexaenoic acid. We conclude that consumers have viable options to reduce average ω-6/ω-3 intake ratios, thereby reducing or eliminating probable risk factors for a wide range of developmental and chronic health problems.

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Available from: Charles Benbrook, May 05, 2014
    • "Recently it has been shown that the concentrations of n-3 LC-PUFA in cow milk can be substantially increased by supplementing the cow diet with feed containing high quantities of n-3 FA (Moghadasian, 2008; Nelson and Martini, 2009; Moate et al., 2013). One study also found that the concentration of n-3 FA, including EPA and docosapentaenoic acid (DPA; C22:5n-3), was higher in organic milk as compared with conventional milk (Benbrook et al., 2013). A recent study into the heritability of lipid classes in milk (SFA, MUFA, and PUFA) suggests that potential to select for a healthy milk composition exists (Penasa et al., 2015). "
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    ABSTRACT: The n-3 long-chain polyunsaturated fatty acids (LC-PUFA) are low-abundance components in milk fat, but have great potential in promoting human health. A comprehensive survey on triacylglycerol (TAG) molecular species in milk that contain at least one type of n-3 LC-PUFA, namely eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid, has been conducted in this work using HPLC-linear trap quadrupole-Orbitrap and HPLC-Triple Quadrupole mass spectrometry techniques. A total of 51 TAG species that contain n-3 LC-PUFA have been identified in bovine milk and their structures assigned. The TAG species containing docosahexaenoic acid were found in much smaller number and at much lower abundance compared with the other 2 types of TAG. An HPLC-Triple Quadruple mass spectrometry-based method was developed, which provides relative quantification of all these TAG species in a run of 36 min. Application of this method to the quantification of n-3 LC-PUFA-incorporated TAG in 32 individual animal milk samples allowed us to determine variation between animals, identify strong metabolic relationships between TAG species, and reveal negative effect of a grape marc supplement on the accumulation of eicosapentaenoic acid in milk.
    No preview · Article · Oct 2015 · Journal of Dairy Science
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    • "The question is whether organic milk actually contains a higher level of beneficial compounds than conventional milk from cows with no access to pasture . Benbrook et al. (2013) examined organic and conventional milk from 14 commercial processors across the USA over an 18-month period , finding higher omega-3 fatty acid concentrations in the organic milk. This work did not deal with milk at the farm level, although it indicates that a transition to organic management could be beneficial to the consumers who purchase the resulting milk. "
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    ABSTRACT: Characteristics of conventional milk and milk from a herd transitioning from nongrazing to organic were studied by comparing adjacent farms over a 12-month period. Levels of short- and medium-chain fatty acids partially responsible for aroma and flavour were initially lower in the milk from the transitioning herd, but not after the cows had settled into an organic diet. Once that point was reached, the amount of α-linolenic acid in the transitioning herd milk exceeded that of the conventional herd. This case study demonstrates that subtle differences occur in the milk as cows transition to organic.
    Full-text · Article · Jul 2015 · International Journal of Dairy Technology
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    • "The Sustainable Agriculture Research Vol. 4, No. 3; 2015 authors of this study (Benbrook et al., 2013) on how organic production enhances milk quality conclude that " increasing reliance on pasture and forage-based feeds on dairy farms has considerable potential to improve the FA [fatty acid] profile of milk and dairy products " and " it is far more common – and indeed mandatory on certified organic farms in the U.S. – for pasture and forage-based feeds " and " improvements in the nutritional quality of milk … should improve long-term health status and outcomes, especially for pregnant women, infants, children, and those with elevated CVD [cardiovascular disease] risk. " Other studies have also reported differences in composition of animal products as a result of pasture feeding. "

    Preview · Article · Jun 2015 · Sustainable Agriculture Research
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