A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef.
Growing consumer interest in grass-fed beef products has raised a number of questions with regard to the perceived differences in nutritional quality between grass-fed and grain-fed cattle. Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability. Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, trans vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis. While the overall concentration of total SFAs is not different between feeding regimens, grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries. Fat conscious consumers will also prefer the overall lower fat content of a grass-fed beef product. However, consumers should be aware that the differences in FA content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A). It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.
Daley
Cynthia A
CA
College of Agriculture, California State University, Chico, CA, USA. cdaley@csuchico.edu
Abbott
Amber
A
Doyle
Patrick S
PS
Nader
Glenn A
GA
Larson
Stephanie
S
D000821:Animal Feed; D000818:Animals; D000975:Antioxidants / Q000032:analysis*; D002417:Cattle; D002523:Edible Grain; D005227:Fatty Acids / Q000032:analysis*; D015525:Fatty Acids, Omega-3 / Q000032:analysis; D043371:Fatty Acids, Omega-6 / Q000032:analysis; D044243:Linoleic Acids, Conjugated / Q000032:analysis; D008460:Meat / Q000032:analysis*; D009829:Oleic Acids / Q000032:analysis; D006109:Poaceae; D013649:Taste; D014810:Vitamin E / Q000032:analysis; D019207:beta Carotene / Q000032:analysis
D000975:Antioxidants; D005227:Fatty Acids; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D044243:Linoleic Acids, Conjugated; D009829:Oleic Acids; D019207:beta Carotene; D014810:Vitamin E; C050413:11-octadecenoic acid