Background/objectives: Objective methods such as the monitoring of salt concentrations in home-prepared dishes may be effective in reducing salt intake. We investigated the effect of monitoring the salt concentration of home-prepared dishes (Monitoring) on salt reduction and change in taste threshold, and the effect of the simultaneous use of low-sodium seasonings (Seasoning) to compare the effect of Monitoring with the conventional method.
Subjects/methods: We conducted a double-blind randomized controlled study using a 2 × 2 factorial design with two interventions. A total of 50 participants (40-75 years-old) were recruited among residents of Niigata Prefecture, a high sodium-consuming population in Japan, then randomly allocated to four groups. After excluding participants with incomplete urine collection, change in salt intake was evaluated using 24-hour urinary excretion as a surrogate of intake for 43 participants. Change in taste threshold was evaluated in 48 participants after excluding those with incomplete threshold measurement.
Results: The Monitoring intervention group showed a significant decrease in sodium intake (-777 mg/24 h), whereas the decrease in the Seasoning intervention group was not significant (-413 mg/24 h). Sodium intake did not statistically differ between the intervention and control groups (-1011 mg/24 h and -283 mg/24 h for Monitoring and Seasoning, respectively). The changes in taste threshold measurement were very small and did not markedly differ between groups.
Conclusions: Monitoring the salt concentration of dishes had a potentially stronger salt-reducing effect than the use of low-sodium seasonings, a conventional method. Confirmation requires additional study with a larger sample size.