Impact of different dietary sodium reduction strategies on blood pressure: a systematic review

High sodium intake was found to be associated with increased blood pressure. Decreasing dietary sodium intake can effectively reduce blood pressure, especially among hypertensive individuals, but the extent of reduction remains debatable. The effectiveness of different sodium reduction strategies on blood pressure reduction was identified in the current review. Randomized controlled trials and clinical trials on dietary sodium intake and blood pressure published from 23 March 2008 to 23 March 2021 were collected from the PubMed database. Twenty-six studies were included and divided into four subgroups based on the types of interventions identified. Subgroups included a low-sodium diet (1) in a group with or without added sodium, (2) through food substitutes, (3) through health education and behavior change, and (4) through salt substitutes. Reduction of dietary sodium intake resulted in a mean difference of 4.51 mmHg (95% CI: 3.35-5.67) in systolic blood pressure and 2.42 mmHg (95% CI: 1.61-3.23) in diastolic blood pressure. The effectiveness of these strategies was approximated from the difference in 24-h urinary sodium excretion between the intervention and control groups, which was 53.74 mmol/day (95% CI: 31.95-75.53). When analyzed, the low-sodium diet without added sodium showed the greatest significant differences in blood pressure (7.58/4.01 mmHg) and 24-h urinary sodium excretion (101.49 mmol/day), whereas the low-sodium diet through food substitutes yielded the lowest significant differences in blood pressure (2.26/0.81 mmHg) and 24-h urinary sodium excretion (25.78 mmol/day). Thus, reducing sodium intake can be an effective strategy for the prevention and treatment of hypertension.