The feasibility of implementing a dietary sodium reduction intervention among free-living normotensive individuals in south west Nigeria

High sodium intake is associated with high levels of blood pressure, both among and within populations. However, there have been few intervention studies from Africa reporting blood pressure changes with dietary reduction of sodium. In this study, we tested the feasibility of achieving a reduction in dietary sodium intake in free-living individuals using a dietary intervention among 82 free-living normotensive adults in southwest Nigeria. The participants, 49 men (mean age 47.2 years) and 33 women (mean age 43.6 years), received dietary advice to reduce sodium intake and maintained the reduced sodium diet for a 2-week period. Blood pressure and 24-hour urinary excretion of sodium were measured at baseline and after two weeks on the reduced sodium diet. Baseline 24-hour urinary sodium excretion was 140.5 (SD 53.4) mmol/24 hours among men and 132.6 (SD 48.0) mmol/24 hours among women. Twenty-four hour urinary sodium excretion fell by 76.9 (95% CI 59.7, 94.1) mmol/24 hours among men, and by 79.4 (95% CI 59.4, 99.1) mmol/24 hours among women. On the low sodium diet, systolic blood pressure fell by 4.7 (95% CI 1.9, 7.4) mm Hg among men, and by 7.0 (95% CI 2.6, 11.4) mm Hg among women while diastolic blood pressure fell by 1.9 (95% CI -0.3, 4.1) mm Hg among men and by 1.6 (95% CI - 1.8, 5.0) mm Hg among women. It is concluded that a significant reduction in sodium intake may be achievable in free-living individuals in this setting using a simple dietary intervention. The findings of this pilot study should encourage more sophisticated intervention studies (such as cross-over trials and double blind randomized clinical trials) in Africans for the elucidation of mechanisms and consequences of hypertension in Blacks.