Nutritional Quality of Organic Milk

Abstract: Over the last century, intakes of omega-6 fatty acids in Western diets have dramatically increased, while omega-3 intakes have fallen. Resulting omega-6/omega-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 omega-6 fatty acids and 62% more omega-3 fatty acids than conventional milk, yielding a 2.5-fold higher omega-6/omega-3 ratio in conventional compared to organic milk (5.77 vs. 2.28). All individual omega-3 fatty acid concentrations were higher in organic milk-alpha-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 omega-6/omega-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 omega-6 fatty acids. The three choices together would decrease the omega-6/omega-3 ratio among adult women by similar to 80% of the total decrease needed to reach a target ratio of 2.3, with relative impact "switch to low omega-6 foods''. "switch to organic dairy products" approximate to "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 omega-6/omega-3 intake ratios, thereby reducing or eliminating probable risk factors for a wide range of developmental and chronic health problems.

Reference: Benbrook, C.M., et al. (2013). Organic Production Enhances Milk Nutritional Quality by Shifting Fatty Acid Composition: A United States-Wide, 18-Month Study, Plos ONE 8(12): e82429. Online: