title: Organic production enhances milk nutritional quality by shifting fatty acid composition: a United States-wide, 18-month study.
abstract: 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.
authors.affiliation: Center for Sustaining Agriculture and Natural Resources, Washington State University, Pullman, Washington, United States of America.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Benbrook
authors.affiliation: School of Agriculture, Food and Rural Development, Newcastle University, Northumberland NE, United Kingdom.
authors.forename: Gillian
authors.initials: G
authors.lastname: Butler
authors.affiliation: Organic Valley/CROPP Cooperative/Organic Prairie, Lafarge, Wisconsin, United States of America.
authors.forename: Maged A
authors.initials: MA
authors.lastname: Latif
authors.affiliation: School of Agriculture, Food and Rural Development, Newcastle University, Northumberland NE, United Kingdom.
authors.forename: Carlo
authors.initials: C
authors.lastname: Leifert
authors.affiliation: Center for Sustaining Agriculture and Natural Resources, Washington State University, Pullman, Washington, United States of America.
authors.forename: Donald R
authors.initials: DR
authors.lastname: Davis
mesh_terms: D000328:Adult; D000818:Animals; D003612:Dairying; D005227:Fatty Acids / Q000032:analysis*; D005260:Female; D005399:Fishes; D005843:Geography; D006801:Humans; D019787:Linoleic Acid / Q000032:analysis; D008892:Milk / Q000737:chemistry* / Q000592:standards*; D009753:Nutritive Value; D058871:Organic Agriculture / Q000379:methods*; D012621:Seasons; D013997:Time Factors; D014481:United States; D055815:Young Adult; D017962:alpha-Linolenic Acid / Q000032:analysis
chemical_list: D005227:Fatty Acids; D017962:alpha-Linolenic Acid; D019787:Linoleic Acid