Grass-fed beef may not have as many healthful traits as some perceive, concludes a Texas AgriLife Research study.
Stephen Smith, an AgriLife Research meat scientist, and a team of researchers found that contrary to popular perception, ground beef from pasture-fed cattle had no beneficial effects on plasma lipid. However, high monounsaturated fat ground beef from grain-fed cattle increased HDL cholesterol, increased LDL particle diameters, and decreased insulin, suggesting that ground beef produced by intensive production practices provides “a healthful, high-quality source of protein.”
"We wanted to see if product from pasture-fed and corn-fed cattle had different effects on LDL or HDL cholesterol," Smith says. "We looked at the scientific literature and couldn’t find any justifications for the statement that pasture-fed beef is better for you. All we found were rat studies in which they were fed omega-3 fatty acids, so we wanted to know if this applied to beef from grass-fed cattle."
The study, funded by the National Cattlemen’s Beef Association, used Angus cattle raised at the McGregor AgriLife Research Center.
- One group of steers was fed a pasture diet with supplement hay and kept on pasture until 20 months of age.
- A second group was fed the same way a feedlot operator would and kept on a corn-based diet until 16 months of age, then reaching USDA Choice status.
- A third group was fed the corn-based diet until reaching USDA Prime. The fat in cattle that are high in marbling is low in saturated and trans-fats, and higher in monounsaturated fats.
Next, a group of 27 men completed a three-way crossover study. Each group rotated, consuming five 114-gram ground beef patties/week for six weeks from each of the three sets of cattle used in the study.
"There really were no negative effects of feeding ground beef from the pasture-fed cattle," Smith says. "We did see many positive effects in men who consumed ground beef from corn-fed cattle. The ground beef from the USDA Prime cattle increased HDL cholesterol and LDL particle diameter. Both effects are protective against cardiovascular disease. The Prime ground beef also decreased insulin, so it may have some protective effect against type II diabetes."
To see the article, go to agnews.tamu.edu/showstory.php?id=1934
-- Texas AgriLife Research release