If you're like most Americans, you probably grew up hearing that milk is an important part of a healthy diet. But research suggests health benefits such as lowering heart disease risk may ultimately depend on a cow's diet.
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Cows consuming an essentially 100 percent organic grass and legume forage-based diet produce milk rich in nutrients that slash the risk of heart disease, diabetes and other illnesses, according to a recent study published in "Food Science & Nutrition."
Researchers from the University of Minnesota, Johns Hopkins University, Newcastle University in England, Southern Cross University in Australia, and the Aarhus University Hospital in Denmark collaborated to analyze over 1,160 samples of whole "grassmilk" over three years, taken from on-farm bulk tanks before processing.
Their results showed that grassmilk cows produce milk with elevated levels of omega-3 and CLA, which provides a significantly healthier balance of fatty acids.
"The improved fatty acid profile in grass-fed organic milk and dairy products (also known as grassmilk) brings the omega-6/omega-3 ratio to a near 1 to 1, compared to 5.7 to 1 in conventional whole milk," according to a press release from the University of Minnesota. "Omega-6 and omega-3 fatty acids are essential human nutrients, yet consuming too much omega-6 and too little omega-3 can increase the risk of cardiovascular disease, obesity, and diabetes."
The data has led some of the researchers to suggest milk suppliers could increase their margins by turning to pasture fed cows.
"With growing consumer demand for organic dairy products, producers may be able to expand their profitability and market share by converting to grass-based pasture and forage-feeding systems," study co-author Dr. Bradley Heins and associate professor of dairy science at the University of Minnesota's West Central Research and Outreach Center, said, according to Express.
For the study, researchers divided cows into three groups based on what they were fed: "grassmilk" cows, "organic" cows and "conventional" cows.
Grassmilk cows consumed an essentially 100 percent organic grass and legume forage-based diet, via pasture and stored feeds like hay and silage. The organic cows ate about 80 percent of their daily Dry Matter Intake (DMI) from forage-based feeds, and 20 percent from grain and concentrates. In contrast, conventional cows consumed rations in which forage-based feeds account for only about 53 percent of daily DMI. The other 47 percent comes from grains and concentrates.
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The research showed that grassmilk provided the highest level of omega-3s (0.05 grams per 100 grams of milk), compared to 0.02 grams per 100 grams in conventional milk. This demonstrated an increase of 147 percent in omega-3s when cows are primarily grass fed.
Additionally, grassmilk contains 52 percent less omega-6 than conventional milk, and 36 percent less omega-6 than normal organic milk. The research team also found that the grassmilk had the highest average level of CLA (0.043 grams per 100 grams of milk). In comparison, the conventional milk contained just 0.019 grams per 100 grams, and the organic milk contained 0.023 grams per 100 grams.
Despite the significantly healthier balance of fatty acids in grassmilk, conventional feeding of cows accounts for the vast majority, or more than 90 percent, of the milk cows on U.S. farms.
However, consumers concerned about their health should definitely consider avoiding conventional milk, according to the researchers.
"The near-perfect balance of omega-6 and omega-3 fatty acids in grassmilk dairy products will help consumers looking for simple lifestyle options to reduce the risk of cardiovascular and other metabolic diseases," Dr. Charles Benbrook, from Johns Hopkins University, said, according to NDTV.
Read the full study at onlinelibrary.wiley.com.