Poster Topical Area: Energy and Macronutrient Metabolism
Location: Hall D
Poster Board Number: 500
Objective: The recognized benefits of generous, balanced intakes of high quality protein to muscle mass and strength in older adults is tempered by concerns about the cardiometabolic impact of dietary sources of animal protein. The objective of this study was to explore the cardiometabolic impact of a protein-enhanced (predominantly lean beef and pork) versus an RDA-level protein weight reduction diet in obese middle-aged and older women and men.
Methods: Obese participants (mean BMI = 37.3 kg/m2; 90% female) aged ≥45 yrs (mean = 64 yrs) were randomly assigned to either an RDA-level protein Control (0.8 grams protein/kg bw) or a balanced, higher Protein (1.2 grams protein/kg bw; 30 grams high quality protein/meal) weight loss diet (500 kcal deficit) for 6 months. Protein participants were provided protein as lean and very lean red meat for 2 of 3 meals daily. Blood samples collected at baseline and study completion were analyzed using nuclear magnetic resonance spectroscopy to quantify cardiometabolic risk factors: lipids, lipoprotein size and number, glycoprotein acetylation (GlycA), trimethylamine-N-oxide (TMAO), and Lipoprotein Insulin Resistance Index (LP-IR) scores.
Results: Completers in both the Control (n = 27) and Protein (n = 53) groups lost weight (6-7%; P < 0.0001) and improved function (6-minute walk; P < 0.0001); they also had reduced fasting triglycerides (P < 0.02), large triglyceride-rich lipoprotein particles (P = 0.02) and plasma glucose (P < 0.003). Neither group experienced a change in total cholesterol, HDL-C, LDL-C, apolipoprotein A-I, apolipoprotein B, or TMAO (all P > 0.05). GlycA levels were reduced in the Control (P = 0.04) but not in the Protein (P > 0.05) group. Low-density lipoprotein particle number (LDL-P) and LP-IR scores were reduced in the Protein (P = 0.04 and 0.0004, respectively) but not in the Control (P > 0.05) group.
Conclusions: While further study in larger samples is warranted, these findings support the conclusion that a balanced, higher protein (predominantly as lean red meat) hypocaloric diet not only leads to weight loss and improved function, but also may benefit insulin resistance (LP-IR) and lessen cardiovascular risk (LDL-P) in obese middle-aged and older adults. These findings have important implications for treatment of sarcopenic obesity and align with recent recommendations that older adults consume generous, balanced amounts of high quality protein throughout the day.
This study was funded by the Beef Checkoff and Pork Checkoff and received additional support from the North Carolina Pork Council, Smithfield Foods, National Institutes of Health (5T32 AG000029), and United States (U.S.) Department of Veterans Affairs Rehabilitation Research and Development Service Program (CDA-2/IK2 RX002348).
Kathryn Porter Starr
Duke University School of Medicine; Durham VA Medical Center
Durham, North Carolina