(EA03-01-25) Endothelial Function Responses to Alterations in Sodium Vary With Energy Intake in Healthy, Normotensive Adults

Scientific conference where the work was recently presented: American Physiology Summit

Date on which the work was previously presented at the scientific conference listed: April 25, 2025

Objectives: High sodium intakes are a key contributor to cardiovascular disease. The Dietary Reference Intakes recommend healthy adults consume < 2,300 mg Na/d, regardless of energy needs. Newer evidence suggests the relation between sodium and blood pressure varies by energy intake. Whether the relation between sodium and endothelial dysfunction, a precursor to atherosclerosis, varies with energy intake in salt-resistant individuals is unknown. Our objective was to determine if the magnitude of change in endothelial function on a low vs high sodium diet differs by energy level.

Methods: Twenty-three healthy young adults (15W/8M, age 28±6 y, BP 109±11/70±8 mmHg, BMI 24.9±2.8 kg/m²) consumed a low sodium (1100 mg Na/d) and a high sodium (6900 mg Na/d) diet for 10 days each in random order. Diets were customized to meet participants’ energy needs. On day 10, endothelial function was assessed via brachial artery flow-mediated dilation (FMD), and mean difference in FMD from the low to high sodium diet (Δ%FMD) was calculated. Participants were stratified based on energy needs: low (1837±196 kcal/d), moderate (2262±58 kcal/d), and high (2543±215 kcal/d).

Results: For all participants, 24h mean arterial pressure did not increase by ≥6 mmHg from the low to high sodium diet, confirming salt resistance. Regardless of energy, %FMD was lower on the high vs low sodium diet (5.4±2.8% vs 7.6±3.7%, p< 0.001). Δ%FMD from the low to high sodium diet was greatest in the low kcal group and smallest in the high kcal group (-2.80±2.6% vs -2.38±3.2% vs -1.44±1.9%) though group differences did not reach statistical significance (p=0.61). The magnitude of change in dietary sodium density (mg Na/kcal, ΔNaDensity) from the low to high sodium diet was greatest in the low kcal group and smallest in the high kcal group (3.2±0.3 mg/kcal vs 2.6±0.1 mg/kcal vs 2.3±0.2, p< 0.001). After controlling for BMI, Δ%FMD was inversely correlated with ΔNaDensity (r=-0.44, p=0.02) such that a greater decline in %FMD is observed with a greater increase in dietary sodium density.

Conclusions: FMD responses to alterations in sodium intake may vary with energy intake. This highlights the need to examine sodium relative to energy in future studies and when developing dietary recommendations to mitigate cardiovascular disease risk.

Funding Sources: AHA/VIVA 23POST1009835; NHLBI R01 HL145055