Altering dietary lysine:arginine ratio has little effect on cardiovascular risk factors and vascular reactivity in moderately hypercholesterolemic adults.

BACKGROUND

Information is scarce regarding the effect of dietary protein type, with specific focus on the lysine-to-arginine (Lys:Arg) ratio, on cardiovascular risk factors and vascular reactivity in humans.

OBJECTIVE

Determine the 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 (21 females and 9 males, >or=50 years, LDL cholesterol>or=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 were observed 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. The low, relative to the high, Lys:Arg ratio diet resulted in lower postprandial VLDL cholesterol (-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 23% lower after the low Lys:Arg ratio diet (P=0.020 for both).

CONCLUSIONS

Diets differing in Lys:Arg ratios had no or small effects on cardiovascular risk factors and vascular reactivity.