Abstract 4151: Relation of Specific Urinary Amino Acids to Blood Pressure: Findings from the INTERMAP Study
Background: Urinary amino acids (AA) can be used not only to estimate objectively primary sources of dietary protein, but also to enhance understanding of relations between protein intake and blood pressure (BP). However, no data are available on the relation of urinary AA to BP from population-based studies of individuals of diverse sociodemographic backgrounds.
Objective and Methods: With control for multiple possible confounders, to assess relations of eight specific urinary AA (alanine, glutamine, glycine, histidine, lysine, serine, taurine, and threonine) to systolic and diastolic BP in 4,600 Chinese, Japanese, UK, and US men and women ages 40–59 from 17 population samples of the cross-sectional INTERMAP Study. Urinary AA were assessed from one timed 24-hour urine collection and BP based on eight measurements/ person at four visits. Urinary concentrations of AA were determined chromatographically (Biochrom 20 Plus AA Analyzer) and converted to μmol/day.
Results: In analyses controlled for age, sex, and country, the following urinary AA considered singly in linear regression analyses were related to systolic and diastolic BP, directly: alanine, glutamine, histidine, lysine, threonine; inversely: taurine (p-values ranged from 0.014 to <0.001). With further adjustment for special diet, body mass index, alcohol intake, dietary variables (AA or vegetable and animal protein, calcium, magnesium, cholesterol, saturated and polyunsaturated fatty acids), and urinary variables (sodium and potassium), glycine and taurine were significantly and inversely related to both systolic and diastolic BP (p-values from 0.005 to <0.001), and serine with diastolic BP only (p<0.003). For example, estimated BP differences for higher urinary taurine excretion by 1959 μmol/day (i.e., approx. 2 SD) were -1.39 mmHg systolic and -1.26 mmHg diastolic. Lysine remained directly associated with systolic BP only (p=0.048). Associations were similar after exclusion of diabetics (n=241) or people on special diets (n=628).
Conclusions: These data indicate that among population-based middle-aged individuals, specific urinary amino acids relate independently to BP. These findings may serve to clarify the influences of amino acids intake and metabolism on BP.