Effect of meal composition on postprandial lipid concentrations and lipoprotein particle numbers: A randomized cross-over study

BACKGROUND It is unclear how high-protein (HP) and high-monounsaturated fat (HMF) meals affect postprandial blood lipids and lipoprotein particle numbers (LPN). PURPOSE To compare a HP versus a HMF meal on postprandial lipid and LPN responses. METHODS Twenty-four participants (age: 36.3±15.0 years; body mass index: 23.6±2.0 kg/m2; 45.8% female) were fed a HP (31.9% energy from protein) and a HMF (35.2% fat and 20.7% monounsaturated fat) meal in a randomized cross-over trial design. Energy and carbohydrate content were the same across meals. Blood samples were drawn in the fasting state and 3 hour postprandial state, and assessed for lipids and LPN. RESULTS Repeated measures analysis showed a significant (p<0.05) treatment by time interaction effect for triglycerides (TG), the primary variable, total high-density lipoprotein particles (T-HDLP) and T-HDLP minus large-buoyant high-density lipoprotein 2b (T-HDLP-LB-HDL2b). HP versus HMF condition led to significantly lower TG at 120 (geometric mean: 90.1 (95% confidence interval (CI): 76.4-106.3) vs. 146.5 (124.2-172.9) mg/dL) and 180 (101.4 (83.1-123.8) vs. 148.7 (121.9-181.4) mg/dL) min and higher T-HDLP at 120 (mean difference: 297.3 (95% CI: 48.6-545.9) nmol/L) and 180 (291.6 (15.8-567.5) nmol/L) min. The difference in T-HDLP by condition was due to the significantly higher small-dense HDLP (T-HDLP-LB-HDL2b) during HP versus HMF condition at 120 (mean difference: 452.6 (95% CI: 177.4-727.9) nmol/L) and 180 (496.8 (263.1-730.6) nmol/L) min. Area under the curve analysis showed that HP versus HMF condition led to significantly lower TG, non-HDLP, and very-low-density lipoprotein particles (VLDLP) responses but significantly less favorable responses in LB-HDL2b particles, T-HDLP-LB-HDL2b, and LB-HDL2b/T-HDLP ratio. CONCLUSION The HP meal led to lower TG, non-HDLP, and VLDLP but less favorable LB-HDL2b, small-dense HDLP, and LB-HDL2b/T-HDLP ratio responses versus a HMF meal. Further studies are needed to confirm these findings over multiple meals.