Raising cows on pasture is better for the environment. Could it be better for our diet too? UCS investigates the role grass-fed beef and milk can play in healthy eating.

By Kate Clancy

Americans love their beef and milk. With about 70 percent of the population consuming one or the other several times a week, the United States is the largest beef producer and one of the largest dairy producers in the world. But this love affair has serious consequences for the health of consumers, the environment, and the cattle themselves.

Many people assume that beef and dairy cows spend most of their lives happily grazing in grassy meadows. The reality is that most cattle in the United States spend significant parts of their lives in crowded feedlots with hundreds or thousands of other animals, eating feed that contains large amounts of grain (primarily corn). While cattle on pasture rarely get sick, those confined to feedlots and fed grain are prone to disease. Most feedlot operators routinely feed antibiotics to prevent illness and accelerate growth. This, in turn, increases the risk of antibiotic resistance in humans. In addition, air and water pollution stemming from mountains of feedlot manure, and the many fertilizers and pesticides used in grain production, exact a heavy toll on the environment and the health of farmers, farm workers, and nearby residents.

Fortunately, there are better ways to raise food animals. Raising cattle on pasture lessens environmental damage, improves animal health, and reduces antibiotic use. Over the past decade, numerous scientific studies have shown that the meat and milk from pasture-raised animals are higher in fats that may confer health benefits on humans. To confirm how strong the findings are, UCS undertook the first comprehensive comparison of fat levels in beef and dairy products from conventionally raised and pasture-raised animals. Our report, Greener Pastures: How Grass-fed Beef and Milk Contribute to Healthy Eating, presents the results of this analysis and examines what health benefits food producers could promote on their product labels.

Not All Fats Are Bad

Nutritionists have long been interested in the total and saturated fat content of meat and milk, and they now agree that lowering the total fat content of our diet is helpful in keeping weight gain under control, and perhaps in lowering the risk of breast cancer. There is also a large and growing body of evidence that fats such as some of the omega-3 fatty acids and conjugated linoleic acid (CLA) may actually protect against—rather than contribute to—disease. (See box for dietary sources of these fats.) 

UCS reviewed the literature supporting the nutrition benefits of omega-3 fatty acids and CLA and found that the strongest case can be made for the effect of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in reducing the risk of heart disease. There is also considerable evidence indicating that another omega-3 fatty acid, alpha-linolenic acid (ALA), may reduce the risk of fatal and acute heart attacks. Scientists are investigating other potential benefits of ALA, including enhanced immune function, but so far these effects have not been shown conclusively. As for CLA, animal studies have shown many positive effects on heart disease, cancer, and the immune system, but there is not yet enough research to demonstrate these benefits in humans.

Weighing the Evidence

UCS surveyed virtually every study in English that compared levels of fats in pasture-raised and conventionally raised animals. For the purposes of our analysis, we selected only those studies that included animals raised solely on pasture, with negligible nutrition obtained from grains or supplements. The selected studies also had to provide sufficient data to calculate fat levels per serving of food—the measure consumers need in order to understand the contribution a given food makes to their total intake of fats and fatty acids.

Our search produced 25 studies conducted in seven countries, and the resulting analysis of fat levels in steak, ground beef, and milk samples led us to the following conclusions:

• Steak and ground beef from grass-fed cattle are almost always lower in total fat than steak and ground beef from conventionally raised cattle.
• Steak from grass-fed cattle tends to have higher levels of the omega-3 fatty acid ALA.
• Steak from grass-fed cattle sometimes has higher levels of the omega-3 fatty acids EPA and DHA.
• Ground beef from grass-fed cattle usually has higher levels of CLA.
  Milk from pasture-raised cattle tends to have higher levels of ALA than milk from conventionally raised cattle.
• Milk from pasture-raised cattle has consistently higher levels of CLA.

Many questions remain about the exact levels of these fats needed to produce definitive health benefits, and until those questions are resolved, consumers who read food labels will see only a few health or nutrition claims on pasture-raised beef and milk in grocery stores. But some labeling claims can be made now. Grass-fed steaks, for example, could be labeled "lean" and their labels could also state that diets low in fat may reduce the risk of cancer.

In the future, depending on the outcome of further research, grass-fed steak might be labeled a good dietary source of EPA/DHA, and some pasture-raised milk might be labeled a good source of ALA. It will not be possible to make nutrition claims for CLA until human studies confirm its benefits.

A Strong Case for Grazing

Though it remains to be seen whether pasture-raised cattle can produce high enough levels of beneficial fatty acids to contribute to human health, we believe the guaranteed benefit of lean beef, combined with higher levels of ALA and CLA in milk and EPA/DHA in beef, warrant greater investment in pasture-based food production systems. Even without nutrition considerations, the environmental, public health, and humane benefits of such systems make a compelling case for their adoption (see box).

Creating a new production system is never simple or easy, and U.S. pasture-based beef and dairy producers in particular confront numerous challenges: What are the best breeds to raise on pasture? How can pastures be managed to produce the kinds of grass and other forage that maintain good body condition and maximize levels of beneficial fats? What should producers in northern states do during seasons when pastures are not available or do not produce high-quality forage? Luckily, U.S. producers can learn from the decades of experience Argentina, Ireland, New Zealand, and other countries have with pasture-based systems.

To complement this expertise, UCS recommends that the U.S. Department of Agriculture and other federal agencies support additional research on the health benefits of omega-3 fatty acids and CLA, pasture management strategies that will optimize the levels of these fats in beef and milk products, and environmental and economic benefits that could be reaped from expanded production of pasture-raised beef and milk. Encouraging the development of a more sustainable system would be a boon to animals, people, and the environment alike.

Kate Clancy is a senior scientist in the Food and Environment Program.

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