Dietary Protein Intake and Blood Pressure Among Vocational High School Students: A Cross-Sectional Study

Background: Hypertension in adolescents represents a growing and increasingly recognized public health concern, principally because elevated blood pressure established during early life frequently persists into adulthood, thereby substantially augmenting the long-term risk of cardiovascular disease widely influenced by dietary habit. Whilst the influences of dietary sodium, refined carbohydrates, and saturated fats on blood pressure regulation are widely recognized in the literature, the specific role of dietary protein intake in adolescent blood pressure remains insufficiently investigated. Aims: This study aimed to determine the nature and magnitude of the association between dietary protein intake and blood pressure among vocational high school students in Indonesia. Participants and Methods: A cross-sectional analytical study involved 88 vocational high school students, selected via proportionate stratified random sampling. Dietary protein intake was assessed employing a validated Semi-Quantitative Food Frequency Questionnaire (SQ-FFQ), and raw dietary data converted into nutritional quantitative values via Nutrisurvey 2007. Blood pressure was measured in accordance with a standardized protocol involving both oscillometric and aneroid sphygmomanometers. Spearman’s rank correlation coefficient was employed to examine the association between dietary protein intake and blood pressure, with statistical significance set at p < 0.05. Results: The majority of participants (n = 59; 67.0%) exhibited protein intake levels exceeding the nationally recommended dietary allowance. Overall, blood pressure values across the study sample remained within the normotensive range, with a mean systolic blood pressure of 110.0 mmHg and a mean diastolic pressure of 71.43 mmHg. Bivariate correlation analysis revealed a significant negative correlation between dietary protein intake and systolic blood pressure (r = -0.217; p = 0.042), as well as a significant negative correlation between protein intake and diastolic blood pressure (r = -0.234; p = 0.028), indicating that higher protein intake was weakly associated with lower blood pressure values in this cohort. Conclusions: A statistically significant, albeit weak, negative correlation was identified between dietary protein intake and both systolic and diastolic blood pressure among the study participants. These findings suggest that higher dietary protein consumption may be inversely associated with blood pressure levels in adolescents, a relationship that warrants further investigation through prospective longitudinal designs. Given the inherent limitations of the cross-sectional study design employed, causal inferences cannot be drawn from the present findings, and confounding by other dietary and lifestyle variables cannot be excluded.