The Study
Nutritional composition of beef: a comparison of commercial North American grass- and grain-finishing systems
This study compared beef from cows that ate grass vs. cows that ate grain, and found that grass-fed beef usually has more good fats and minerals. But it didn’t make the cows eat different things — it just looked at what was already being sold. So we can say grass-fed beef often has more of these nutrients, but we can’t say eating it will make you healthier.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
This study looked at real beef from stores and farms to see if grass-fed beef is better for you than grain-fed beef.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 517 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The omega-3 difference is small in absolute terms — eating 100g of grass-fed beef gives you about 30mg more omega-3s than grain-fed, which is less than a single salmon fillet.
- 2But it’s still a meaningful boost if you don’t eat fish.
- 3Grass-fed beef had 65% more omega-3s and 2-3x less omega-6s than grain-fed beef.
- 4It also had more calcium, copper, iron, and selenium.
- 5But some grass-fed beef from stores had omega-3 levels as low as grain-fed beef.
- 6Beef from diverse pastures with legumes had the best omega-3 levels.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Animal Science
Year
2025
Authors
J. Varre, Travis Statham, Autumn F Smith, M. Ahsin, J. Cloward, Marina Carbonell Herrera, Camille Mittendorf, Chyanne Crompton, Robert E. Ward, Tiffany Evans, T. Bird, S. Lyons, Amanda Pinelli, Dan Kittredge, S. van Vliet
Related Content
Claims (7)
Certain grain-fed beef, when cattle are finished with shorter feeding periods and more alfalfa silage, contains omega-6 to omega-3 fatty acid ratios below 5:1.
The omega balance metric, which calculates omega-3 as a percentage of all polyunsaturated fats, is a more accurate and informative measure of beef fat quality than the omega-6 to omega-3 ratio because it does not plateau at low values and more clearly distinguishes high-quality from low-quality fat profiles.
Grass-fed beef has a lower ratio of omega-6 to omega-3 fats and higher levels of several fatty acids and minerals compared to grain-fed beef, based on average measurements from analyzed samples.
Beef from cows raised on pastures with a variety of plants including legumes and forbs contains a higher proportion of omega-3 fatty acids relative to other polyunsaturated fats compared to beef from cows raised on less diverse pastures.
Grass-fed beef varies greatly in its omega-3 and omega-6 fat content, and some products sold as grass-fed have fat profiles similar to grain-fed beef, meaning the label 'grass-fed' does not guarantee better nutritional quality.
In the United States, there is no legal standard for the term 'grass-fed,' so animals can be labeled as grass-fed even if they are fed a lot of grain.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.