BMC Public Health. 2026 Jul 21. doi: 10.1186/s12889-026-28605-5. Online ahead of print.
ABSTRACT
BACKGROUND: South Africa has strong public health initiatives targeting salt reduction, yet population-level evidence and strategies regarding potassium intake remain limited. This gap is important given the role of potassium in mitigating sodium-related increases in blood pressure and cardiovascular disease risk. This study assessed potassium intake using dietary and urinary measures in young adults from the African-PREDICT study.
METHODS: Potassium intake was estimated using three 24-hour dietary recalls and a single 24-hour urine collection per participant. Agreement between methods was evaluated using Bland-Altman analysis.
RESULTS: Median potassium intake was 1911 mg/day from dietary assessment and 1683 mg/day from urinary analysis, both well below the recommended 3510 mg/day level, which is linked to sodium counterbalance and reduced cardiovascular risk. Over 90% of participants failed to meet the recommended intake across methods. Black participants and individuals of low socioeconomic status (SES) had substantially lower potassium intakes than their counterparts. Bland-Altman analysis demonstrated limited individual-level agreement (with a 95% limit-of-agreement span of approximately 5,600 mg/day), with dietary potassium intake marginally higher than urinary excretion (mean difference = 61 mg/day; p = 0.19), reflecting expected physiological potassium handling. In adjusted regression analyses, dietary potassium was inversely associated with diastolic blood pressure, while both urinary potassium and the sodium-to-potassium ratio showed no significant associations.
CONCLUSION: Both methods show that potassium intake is low among young adults in South Africa, particularly among Black and low-SES groups, highlighting the need for population-level strategies to increase potassium consumption, particularly in vulnerable groups. The sodium-to-potassium ratio was associated with blood pressure only in the unadjusted model, whereas dietary potassium was associated with diastolic blood pressure in the adjusted model. Dietary assessment may be appropriate for population-level estimation of potassium intake, but its limited agreement with urinary potassium excretion at the individual level, particularly at higher intakes, may limit its utility for individual assessment.
PMID:42477665 | DOI:10.1186/s12889-026-28605-5