We often get questions about the safety, nutritional qualities, environmental benefits, taste and texture of beef that comes from cattle with different types of diets (we like the way Beef Checkoff describes this here). There are many rumors and myths out there, which Penn State's Dr. John Comerford has addressed in a recent blog post. We have also included some nutritional insight from Best Food Facts registered dietitian, Sarah Downs. Here are a few highlights:
When looking at the environmental impacts of grass- and grain-fed beef, "there is a 500% increase in greenhouse gas emissions for each pound of beef produced from grass-fed compared to grain-fed cattle. Uncontrolled nitrogen and phosphate release to the environment, 35% more water use, and 30% more land use for grass-fed cattle compared to grain-fed increases the environmental impact of strictly grass feeding."
Dr. Comerford also seeks to set straight several misconceptions and rumors about the healthfulness of grass-fed compared to grain-fed beef. Here are some of the facts he outlines:
- Some people have stated that there is a greater amount of conjugated linoleic acid, or CLA, in grass-fed beef. CLA has been shown to decrease tumor growth in mice in laboratory studies, so you can understand why this is an important finding. It is true that raw grass-fed beef consistently has twice the CLA content (as a proportion of total fat) than raw grain-fed beef. However, this is irrelevant because studies show when the meat is cooked, there is no difference in CLA content because a large amount of the fat is lost in cooking. Even if people ate the meat raw, you would have to eat 176 pounds of grass-fed beef daily to get the level fed to the mice in the original CLA study (Ha et al, 1987).
With several recent food recalls, the safety of our food is of high importance. Dr. Comerford addresses this as well.
- The advertisements for grass-fed beef that claim there are no chances of E. coli infection in humans from grass-fed beef are scary and dangerous, because it gives consumers a false sense of security. In the case of E. coli, this contamination happens in a processing plant and has nothing to do with how or where the animal was raised. Cattle in all types of environments - feedlots and pasture - have been shown to have the virulent form of E. coli in their digestive tract, and it requires the special care that is taken in beef processing plants to prevent meat contamination. It also requires consumers to use safe handling and cooking methods common to all foods for their safety, and these false claims do not diminish that need.
What about the omega-3 fatty acids in grain fed vs grass-fed beef? Is there a difference? Sarah Downs, MBA, RDN provides some insight.
- Ultimately, the nutrition of grass-fed versus grain-fed beef is very similar. Grass-fed beef does in fact high a higher amount of omega-3 fatty acids (these are healthy fats!) than grain-fed beef. However, this small amount is not significant enough to be able to make it a great source of omega-3 fatty acids. The American Heart Association recommends foods like fatty fish (salmon, trout, and sardines to name a few), walnuts and flaxseeds as the primary source of omega-3 fatty acids.
Here are some great resources from the Academy of Nutrition and Dietetics on omega-3 fatty acids.
In a nutshell, Dr. Comerfield says, "The reality is there is no evidence whatsoever that grass-fed beef has any advantage for safety, human health, or impact on the environment than grain-fed beef. Both types of beef deliver the important factors of nutrition in the human diet of protein, iron, and zinc in equal proportions."