Abstract P037: 24-hour Urinary Amino Acid Excretion And Blood Pressure: The Intermap Study

Background: Available data indicate inverse relations to blood pressure (BP) of dietary vegetable protein and its main amino acid, glutamic acid, also direct relations to BP of meat and animal protein intakes. Data on association of urinary amino acids (UAAs) with BP are limited. Objective: To assess the relationship between UAAs and BP. Methods: This study assessed relations to BP of 21 urinary amino acids among 4,677 men and women ages 40-59 (17 population samples in China, Japan, UK, USA) from the International Study on Macro/Micronutrients and Blood Pressure (INTERMAP). Urinary amino acid excretion was expressed as log transformed value of each urinary amino acid (μmol/24 h), and as % dietary total protein (based on urinary urea nitrogen excretion). Results: In multivariate analyses with all 21 UAAs considered together, independent inverse relations to BP were found for serine, glycine, and lysine, and independent direct relations to BP for threonine, cystine, and 3-methylhistidine, controlling for possible non-dietary and dietary confounders (including body mass index and each of the other UAAs). For example, with log urinary serine at 75th compared to the 25th percentile, SBP/DBP was lower by 2.4/1.8 mm Hg and 2.2/1.7 mm Hg on average without and with adjustment for body mass index in multivariate models. With log urinary 3-methylhistidine at 75th compared to the 25th percentile, SBP/DBP was higher by 3.8/2.7 and 1.6/1.4 mm Hg. Conclusions: These significant new findings on relations to blood pressure of urinary amino acids need to be verified by additional - including prospective - data.