Amino acids incidence of hypertension in a Dutch older population: the Rotterdam study

Background Epidemiological studies have shown an association between dietary protein and hypertension, which may be attributed to specific amino acids (AAs). We examined the relation of dietary arginine, cysteine, lysine, proline and tyrosine with incident hypertension in 1958 men and women from the Rotterdam Study, aged =55 years, who were not treated with antihypertensive medication and were normotensive at baseline. Methods HRs (95% CI) were calculated in tertiles of AA intake (expressed as percentage of total protein intake), using a Cox proportional model with adjustment for age, gender, BMI, smoking, alcohol intake, education, and intake of energy and several nutrients. Results Mean systolic and diastolic blood pressure levels were 122±12 mm Hg and 69±9 mm Hg and dietary protein intake was 82±20 g/day (~17 en%). Arginine (with nuts being the main source) contributed 5.3±0.4% of total protein intake, cysteine contributed 1.4±0.1% (main source: grain), lysine 6.8±0.4% (main source: meat), proline 7.4±0.6% (main source: dairy and grain), and tyrosine 3.7±0.1% (main source: dairy). Intake of these AAs was not significantly associated with incident hypertension (HRs ranging from 0.84 to 1.15; ptrend =0.15). We observed, however, a tendency towards an increased risk for lysine (HR upper tertile vs lower tertile 1.15; ptrend=0.21) and towards a decreased risk for tyrosine (HR 0.86; ptrend=0.15). Conclusion We found no significant associations between AAs, and incidence of hypertension in this older population. There was, however, a tendency towards an adverse effect of lysine and a beneficial effect of tyrosine, which warrants further investigation in larger prospective studies.