The data on nutrient content of beef are done using cuts of beef. We don't know of a commercial lab that would conduct the analysis that you are requesting. Scientists at California State University-Chico (CSUC) recently conducted a comprehensive review of research on the nutrient content of grass-fed beef. The following is a brief summary of their review:
- Although beef is not a significant source of beta-carotene (pro-vitamin A), grass-fed beef furnishes approximately two times the beta-carotene content of that raised on a concentrate-based diet. It also provides a three-fold increase in vitamin E.
- The typical American diet contains an imbalance of 10 to 20 times more omega-6 fatty acids than omega-3 fatty acids. A more appropriate omega-6 intake would be no greater than four or five times than that of omega-3. An ideal ratio would be 2 to 1. Concentrate-fed beef has a ratio of about 4 to 1. The ratio in grass-fed beef is approximately 2 to 1.
- In recent years, numerous human health benefits have been attributed to an increased consumption of conjugated linoleic acid (CLA), which is synthesized in the rumen of cattle and other ruminants. Beef raised on grass-based diets contains two to three times more CLA than beef from cattle fed concentrate-based diets.
- It is important to note, however, that an average 3.5 oz serving of beef, whether it be grain-fed or grass-fed, contains only a fraction of the omega-3 fatty acids (8% vs. 13%) or CLA (10% vs. 25%) recommended in the human diet (Abbott et al., 2004, College of Agriculture, CSUC, and Univ. of California Cooperative Extension Service).
