A: While all types of cow’s milk are equal when it comes to protein, calcium and vitamin D, emerging science shows that milk from cows eating grass may have a nutrition advantage. Milk from cows that graze on grass—versus eating a grain-based diet—is a better source of a healthy fat.
Research shows that milk from grass-fed cows has more conjugated linoleic acid (CLA) than conventional milk. CLA, a fatty acid found in dairy and beef, is linked to protection from colorectal and breast cancers, diabetes and heart disease. A 2010 study from the Harvard School of Public Health found that people with the highest levels of CLA in their body had a lower risk of heart attack than those with the lowest levels.
The main dietary sources of CLA are meats from ruminant animals (e.g., cows, sheep, goats and camels) and dairy products. Milk, cheese and yogurt contain 3.5-4.8 mg. of CLA per gram of fat; beef is quite similar at 2.5-5.6 mg. of CLA per gram of fat.
Scientific studies indicate that the health benefits of CLA are achieved at intakes much higher than what is currently consumed in people’s diets. And although CLA might have some health benefits, the foods that contain CLA also contain saturated fat, which is associated with a higher risk of heart disease.
Another health claim is that milk from grass-fed cows contains more omega-3 fats, which are also regarded as healthy. Like CLAs, it’s vital to look at amounts of omega-3s. While milk from grass-fed cows is higher in omega-3 fats than milk from grain-fed cows, a cup still has only 18 milligrams. The USDA Nutrient Database states that a four-ounce serving of grass-fed top sirloin contains 65 milligrams of omega-3 fats. Compare grass-fed milk and beef to the omega-3 powerhouse king salmon: it contains with 1,270 milligrams per 3 ounces! Recommendations on the quantity of omega fats needed vary between 300–1,000 milligrams per day.
What does this mean as related to Americans’ current eating habits? The bottom line is that milk from grass-fed cows is probably better for you, but only by a little bit.
American Dairy Association North East is one of 19 state and regional promotion organizations working under the umbrella of the United Dairy Industry Association. It is the local affiliate of the National Dairy Council®, which has been conducting nutrition education and nutrition research programs since 1915. For more information, visit www.americandairy.com.