(P42-28-26) Study Protocol: A Comparative Efficacy Study of Sodium Reduction Strategies to Inform Future Dietary Recommendations

Objectives: Current guidelines recommend healthy adults consume < 2,300 mg sodium/day to mitigate cardiovascular (CVD) risk. Sodium intake is strongly positively correlated with calorie intake, making it challenging for some to achieve sodium recommendations. Additionally, the strength of the relation between sodium intake and both blood pressure and vascular endothelial function varies with energy intake. Setting one absolute sodium intake recommendation without consideration for energy may be impractical. A better way to examine sodium intake in relation to CVD risk may be to use dietary sodium density (i.e. mg Na/kcal/day). To date, no study has directly compared the efficacy of a sodium reduction intervention based on current guidelines (i.e. one absolute sodium intake recommendation for all) versus an intervention based on reducing sodium density for improving CVD risk factors. The objective of this pilot study is to explore whether reducing dietary sodium density improves CVD risk factors more consistently than reducing absolute sodium intake.

Methods: This pilot study is a triple-masked, randomized, crossover, controlled feeding study. Twenty healthy middle-aged adults (age 45-65 y) who habitually consume ≥2,300 mg sodium/day will consume two controlled diets for 14 days each in randomized order: a low absolute sodium (2,300 mg/day) diet and a low sodium density diet (1.2 mg/kg/day). Diets will be isocaloric and designed to meet participants’ estimated energy needs. Diets will be separated by a ≥14-day washout period. Dietary compliance will be assessed via 24-hour urine collection. Endothelial function will be assessed at the end of both diets via brachial artery flow-mediated dilation (FMD). Seated and 24-hour ambulatory blood pressure (BP) will also be assessed. Differences between diets and interindividual variability within diets in BP and FMD will be reported.

Results: Participant enrollment and data collection are ongoing.

Conclusions: This study will provide preliminary data to inform future investigations into personalizable guidelines for sodium intake. The long-term goal with this line of work is to optimize dietary sodium recommendations to improve adherence and effectively reduce CVD burden.

Funding Sources: UF-FSU Clinical and Translational Science Award, U.S Department of Agriculture, FSU Council on Research and Creativity