Blog by Chuck Benbrook and Don Davis
We started our research in 2011 comparing the fatty acid profile of whole milk from cows managed conventionally and on organic farms, and now in our new paper, on grassmilk farms.
Our first paper in December 2013 describes how organic management improves the fatty acid levels and quality of milk fat. Organic milk showed sizable increases in omega-3 fatty acids and conjugated linoleic acid (CLA), plus markedly lower levels of omega-6 fatty acids.
The 2013 paper is online in the journal PLOS ONE, here.
Our new paper, accessible here, reports even more impressive and positive shifts in the fatty acid profile of grassmilk—milk from cows fed essentially 100% on pasture and stored grass and legume forage-based feeds, with no mature grains or soy permitted.
In whole grassmilk, total omega-3s rise from 0.0198 grams per 100 grams of conventional milk (g/100 g) to 0.0489 g/100 g, a 147% increase. CLA levels more than double, rising from 0.0192 to 0.0431 g/100 g milk. Total omega-6 fatty acids decrease by more than half, from 0.098 to 0.0454 g/100 g.
The consistency and magnitude of the differences between conventional milk and grassmilk are striking, and surprised the research team. They are also encouraging, since a large body of research links higher daily intakes of omega-3s and CLA to improved health.
To assess the possible impact of mostly full-fat grassmilk dairy products on typical diets, we modeled daily fatty acid intakes for a 30-year old woman consuming a typical U.S. diet. We quantified changes in total dietary intakes of omega-3 and omega-6 fatty acids across some three-dozen diet scenarios, reflecting various combinations of three simple changes in food choices:
- Switching from conventional milk to organic or grassmilk, and/or
- Consuming 4.5 instead of 3 daily servings of dairy products, and/or
- Reducing total omega-6 intake by swapping three high-omega-6 foods for similar foods relatively low in omega-6 content (e.g., tortilla chips for pita chips).
Shifting from conventional to grassmilk dairy products has the most dramatic and positive impact on total omega-3 and CLA intakes.
Three daily servings of grassmilk-based dairy products provide about 300 milligrams of CLA, about three-fourths of the target intake for adult men and 100% of target levels for adult women (target levels are two-thirds of the daily intake levels shown to reduce the risk of cancer). Comparable intakes of conventional dairy products would supply less than half as much CLA.
For omega-3 fatty acids (ALA), three daily servings of grassmilk-based dairy products would deliver about 22% of daily needs for adult men, and 32% for adult women. Conventional dairy products would supply well less than half of these amounts.
In our modeled diets, the three daily servings of grassmilk dairy products supply up to 58% of average total daily omega-3 intakes, making the dairy food group by far the primary source of omega-3 fatty acids across all food groups.
But dairy supplies relatively little omega-6s—less than 10% of the total in our modeled diets. Most of the omega-6 in the American diet today comes from fried foods and vegetable oils in pastries, dips, salad dressings, and a wide range of processed foods.
The switch from conventional to organic to grassmilk production enhances the nutritional quality of milk fat along a continuum. It is not necessary for dairy farmers to go all the way to essentially 100% forage-based feeds to substantially improve the quality of milk fat.
For people striving to lower their risk of cardiovascular and other metabolic diseases, for pregnant and lactating women, and for infants and children, the greater omega-3 and CLA intakes from grassmilk should help tip the odds toward improved health.
Dairy farmers looking for ways to lower costs and increase profit margins might give a close look at options for shifting away from high-production, high-cost systems heavily reliant on purchased grains and concentrate feeds.
With the right mix of land, animal genetics, a steady market, and experience plus timely guidance, other important benefits become obtainable on grassmilk farms. These include healthier animals and soils, a lower environmental footprint, and a greater degree of self-reliance.
Hence, a wide array of benefits for consumers, farmers, animals, and the environment will follow a shift toward forage-based feeds. We need to seriously consider how such a shift can be made easier and more profitable through targeted R+D and infrastructure investments, than current practices in the U.S. dairy industry.
For more on the study, the fatty acid profile of milk, and health implications, see the study’s landing page.