Benefits of Monounsaturated Fatty Acids in Human Health 

                                                             37th Annual
                                        Texas Human Nutrition Conference

        
                         Dr. Stephen B. Smith, TAMU, Bill Fielding and JoJo Caralles, HeartBrand Beef

                                                Slippery Slope to Health:
                                       Adding Good Fat Back to the Diet

                Stephen B. Smith, PhD, Professor, Department of Animal Science, Texas A&M University

The general public perceives beef from pasture-fed cattle as reducing risk factors for cardiovascular disease (CVD).  However, because pasture feeding results in beef that is high in saturated fatty acid (SFA) and trans-fatty acids (TFA), this is a misconception. Beef from grain-fed cattle is naturally high in monounsaturated fatty acids (MUFA) and, therefore, should be better suited to reduce risk factors for CVD.  Over the course of several studies, we established that ground beef from grain-fed cattle increased high-density lipoprotein cholesterol (HDL-C) and often lowered triacylglycerols (TAG) compared to ground beef from pasture-fed cattle.  In one study, mildly hypercholesterolemic men consumed high-fat hamburger that contained high amounts of SFA and TFA (from pasture-fed cattle) or hamburger that contained high amounts of MUFA (from grain-fed cattle).  In a second study, normolipidemic men were fed ground beef from pasture-fed cattle, from normal feedlot cattle, and from cattle that had been feedlot-fed for an extended period to enrich the beef with MUFA.  In a third study, postmenopausal women were fed inexpensive chubpack ground beef (high in SFA and TFA) or ground beef from Japanese Akaushi cattle (high in MUFA).  In all studies, treatments consisted of consuming five, 114-g ground beef patties per week of different MUFA:SFA for 5-wk followed with intervening 4-wk washout periods.  In all studies, consumption of the high-MUFA hamburger or ground beef increased HDL-C over initial values and depressed plasma TAG.  Furthermore, high-MUFA ground beef increased LDL particle diameters, which has been associated with reduced risk for CVD.  We conclude from our studies that, contrary to popular perception, ground beef from pasture-fed cattle had no positive effects on plasma lipids.  Similar results were observed in women consuming chubpack ground beef.  In contrast, high-MUFA ground beef from grain-fed ("feedlot") domestic or Japanese Akaushi cattle increased HDL-C and LDL particle diameters, and decreased plasma TAG, indicating that ground beef produced by intensive production practices provides a healthful, high-quality source of protein. 

              
       Janie Bain, American Akaushi Association                              Casey Brinlee, HeartBrand Beef