Submitted to: Atherosclerosis
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/2/2009
Publication Date: 12/5/2009
Citation: Lichtenstein, A., Vega-Lopez, S., Matthan, N., Ausman, L., Harding, S., Rideout, T., Ai, M., Otokozawa, S., Freed, A., Kuvin, J., Karas, R., Jones, P., Schaefer, E. 2009. Altering dietary lysine: arginine ratio has little effect on cardiovascular risk factors and vascular reactivity in moderately hypercholesterolemic adults. Atherosclerosis. 210(2):555-562. Interpretive Summary: There has been sporadic interest in the effect of dietary protein type on cardiovascular risk factors and vascular reactivity with specific focus on the amino acid profile of the diet (lysine to arginine [Lys:Arg] ratio). The objective of the study was to determine effect of dietary Lys:Arg ratio on cardiovascular risk factors and vascular reactivity in moderately hypercholesterolemic adults. The design was a randomized cross-over design with two 35-day diet phases involving thirty adults greater than 50 years of age with LDL cholesterol concentrations greater than 120 mg/dL. Each of the two diets contained 20% energy (E) as protein, 30%E as fat, 50%E ascarbohydrate, and were designed to have low (0.7) or high (1.4) Lys:Arg ratio. The obtained results suggest that dramatic shifts in dietary Lys:Arg ratio had no or small effects on cardiovascular risk factors and vascular reactivity. Thus, possible roles of Lsy:Arg ratio in controlling cardiovascular risk may be minimal.
Technical Abstract: Background: The effect of dietary protein type on cardiovascular risk factors and vascular reactivity, with specific focus on the lysine to arginine (Lys:Arg) ratio, has been studied sporadically. Objective: Determine effect of dietary Lys:Arg ratio on cardiovascular risk factors and vascular reactivity in moderately hypercholesterolemic adults. Design: Randomized cross-over design of two 35-day diet phases; thirty adults (=50 y, LDL cholesterol =120 mg/dL). Diets had 20% energy (E) protein, 30%E fat, 50%E carbohydrate and were designed to have low (0.7) or high (1.4) Lys:Arg ratio. Measures included fasting and postprandial lipid, lipoprotein, apolipoprotein concentrations; fasting high sensitivity C-reactive protein (hsCRP), small dense LDL (sdLDL)-cholesterol, remnant lipoprotein cholesterol (RemLC), glycated albumin, adiponectin and immunoreactive insulin concentrations, endogenous cholesteryl ester transfer protein (CETP) and lecithin:cholesterol acyl transferase (LCAT) activities; cholesterol fractional synthesis rate (FSR); and flow mediated dilation (FMD) and peripheral artery tonometry (PAT). Results: No differences in fasting and/or postprandial total, LDL, HDL and sdLDL cholesterol, RemLC, Lp(a) or apo B concentrations, LCAT and CETP activities, FSR, glycated albumin, immunoreactive insulin, FMD or PAT were observed. The low, relative to the high, Lys:Arg ratio diet resulted in lower postprandial VLDL cholesterol (-49 24%, P=0.001) and triglycerides (-23%, P=0.001), and small but significant differences in fasting (-3%, P=0.003) and postprandial (-3%, P=0.018) apo AI, and fasting adiponectin concentrations (+7%, P=0.035). Fasting and postprandial hsCRP concentrations were lower after the low Lys:Arg ratio diet 52 (-23%, P=0.020 for both). Conclusions: Dramatic shifts in dietary Lys:Arg ratio had no or small effects on cardiovascular risk factors and vascular reactivity.