Charles M. Benbrook1*, Gillian Butler2, Maged A. Latif3, Carlo Leifert2, Donald R. Davis11 Center for Sustaining Agriculture and Natural Resources, Washington State University, Pullman, Washington, United States of America, 2 School of Agriculture, Food and Rural Development, Newcastle University, Northumberland NE, United Kingdom, 3 Organic Valley/CROPP Cooperative/Organic Prairie, Lafarge, Wisconsin, United States of America

Over the last century, intakes of omega-6 (v-6) fatty acids in Western diets have dramatically increased, while omega-3 (v-3) intakes have fallen. Resulting v-6/v-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 v-6 fatty acids and 62% more v-3 fatty acids than conventional milk, yielding a 2.5-fold higher v-6/v-3 ratio in conventional compared to organic milk (5.77 vs. 2.28). All individual v-3 fatty acid concentrations were higher in organic milk—a-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 v-6/v-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 v-6 fatty acids. The three choices together would decrease the v-6/v-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 v-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 a-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 v-6/v-3 intake ratios, thereby reducing or eliminating probable risk factors for a wide range of developmental and chronic health problems.

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PLOS ONE | www.plosone.org 13 December 2013 | Volume 8 | Issue 12 | e82429