Organic Milk: A Heart-Healthy Recipe?

The increase in obesity among Americans and the high saturated fat content of the average American diet have together triggered widespread nutritional recommendations to decrease the intake of whole milk and other high-fat dairy products. In addition, manufacturing and processing pressures have led to food processing practices that may further compromise the nutritional content of milk. Recent data published in PLoS One raise questions about whether these practices may actually be reducing the average American’s intake of beneficial omega-3 (ω-3) fatty acids. Concurrently, the consumption of omega-6 (ω-6) fatty acids in the US population is rising. Although the optimal ω-6 to ω-3 ratio should be near 2.3, the current national ratio is estimated to be much higher-between 10 and 15-and therefore, to be nutritionally undesirable.

The study was led by a group at Washington State University and sought to assess the impact of organic whole milk compared with conventional whole milk, with particular attention paid to the ratio of ω-6 to ω-3 fatty acids between these products. In this large, national study of US milk manufacturing processes, there was a significant difference in this ratio (5.77 vs 2.28) between conventional and organic milk; the latter had 25% fewer ω-6 fatty acids and 62% more ω-3 fatty acids and was therefore more nutritionally sound than conventional milk. In addition, organic milk was higher in all beneficial ω-3 fatty acids (α-linolenic acid [by 60%], eicosapentaenoic acid [by 32%], and docosapentaenoic acid [by 19%]).

Hypothetical dietary patterns were also modeled to assess milk-based differences in overall ω-6 to ω-3 ratios. Three dietary patterns emerged, which might positively affect Americans’ dietary ω-6 to ω-3 fatty acid ratio by up to 80%: (1) high instead of moderate dairy consumption; (2) organic vs conventional dairy products; and (3) reduced vs typical consumption of ω-6 fatty acids.

The study should raise the medical community's awareness of how national food-processing practices may alter the nutritional content of commonly consumed food products. Practitioners can offer their patients the above dietary tips to help them improve their ω-6 to ω-3 fatty acid intake ratio, moving it closer to the desired value of 2.3. Such a change in diet might have a positive impact on future heart health and potentially reduce risk factors for other chronic health problems. However, the nutritional consequences of consuming whole milk vs low-fat or fat-free milk still remain unknown and warrant further investigation.

References:

Benbrook CM, Butler G, Latif MA, et al. Organic production enhances milk nutritional quality by shifting fatty acid composition: a United States–wide, 18-month study. PLoS One. 2013;8:1-13.e82429. doi:10.1371/journal.pone.0082429. (Full text PDF.)