Amino Acid Intake Is Inversely Associated with Arterial Stiffness and Central Blood Pressure in Women

Background: Although data suggest that intake of total protein, and specific amino acids (AAs) reduces blood pressure, data on other cardiovascular disease risk factors are limited. Objective: We examined associations between intake of AAs with known mechanistic links to cardiovascular health and direct measures of arterial stiffness, central blood pressure, and atherosclerosis. Methods: In a cross-sectional study of 1898 female twins aged 18–75 y from the TwinsUK registry, intake of 7 cardioprotective AAs (arginine, cysteine, glutamic acid, glycine, histidine, leucine, and tyrosine) was calculated from foodfrequency questionnaires. Direct measures of arterial stiffness and atherosclerosis included central systolic blood pressure (cSBP), mean arterial pressure (MAP), augmentation index (AI), pulse wave velocity (PWV), and intima–media thickness (IMT). ANCOVA was used to assess the associations between endpoints of arterial stiffness and intake (per quintile), adjusting for potential confounders. Results: In multivariable analyses, higher intake of total protein and 7 potentially cardioprotective AAswas associatedwith lower cSBP, MAP, and PWV. Higher intake of glutamic acid, leucine, and tyrosine was most strongly associated with PWV, with respective differences of20.46 0.2 m/s (P-trend = 0.02),20.46 0.2 m/s (P-trend = 0.03), and20.46 0.2 m/s (P-trend = 0.03), comparing extreme quintiles. There was a significant interaction between AA intake and protein source, and higher intake of AAs from vegetable sourceswas associated with lower central blood pressure and AI. Higher intake of glutamic acid, leucine, and tyrosine from animal sources was associated with lower PWV. Conclusions: These data provide evidence to suggest that intake of several AAs is associatedwith cardiovascular benefits beyond blood pressure reduction in healthy women. The magnitude of the observed associations was similar to those previously reported for other lifestyle factors. Increasing intake of these AAs could be an important and readily achievable way to reduce cardiovascular disease risk. J Nutr doi: 10.3945/jn.115.214700.