Chronobiology of Meal Timing in Early-Stage Hypertension: Effects on Renal and Vascular Function

Introduction: Effective lifestyle strategies are urgently needed for young adults with early-stage hypertension to prevent progression. A Western diet has been shown to stress the kidney, increase blood pressure and induce vascular dysfunction. The effects of time-of-day of eating (chrono-nutrition) on postprandial renal and vascular physiology are understudied in clinical trials. We hypothesized that when a Western-style meal is consumed during the circadian inactive phase, when the kidney clock is inactive, nocturnal blood pressure dipping would be impaired and renal sodium clearance would not be different between groups, indicative of prolonged sodium retention following circadian-misaligned eating. Methods: Ten adults with elevated or stage 1 hypertension (Mean±SD; 26±8 years, 50% female) underwent a randomized crossover, controlled feeding intervention. Participants were allocated to receive a Western-style meal high in sodium, sugar and saturated fat in the morning (MMC) or in the evening (EMC). Participants completed 24-hour ambulatory blood pressure monitoring and simultaneous urine collection. Results: Resting systolic (124.7±4.5 mmHg) and diastolic blood pressure (80.1±6.1 mmHg) was confirmed at screening. Daytime fractional excretion of sodium was increased after MMC (EMC vs. MMC: 0.35±0.13% vs. 0.84±0.28%, p =0.008). However, after EMC nighttime sodium excretion was not elevated (0.39 ± 0.30% vs. 0.48 ± 0.24%, p =0.314), suggestive of overnight sodium storage. Markers of kidney stress including proteinuria ( p =0.018) and urinary neutrophil gelatinase-associated lipocalin ( p =0.066) were elevated following MMC. There was a clinical meaningful increase in systolic (121.2±6.3 vs. 126.3±6.1mmHg, p =0.028), diastolic (77.4±6.4 vs. 80.6±4.8mmHg, p =0.028), and mean arterial (90.8±5.7 vs. 94.9±4.6 mmHg, p =0.028) blood pressures during waking hours after MMC. Following the EMC, nocturnal blood pressure elevation was mitigated, presumably through protective sodium storage mechanisms (systolic pressure dipping:12.3±4.7% vs.15.5±4.5%, p =0.249). Compared to the MMC phase there was an increase in resting systolic blood pressure the morning following EMC (121.8±9.3 vs. 119.0±7.8 mmHg, p =0.018). Conclusions: This study demonstrates that a Western-style meal increases kidney stress and blood pressure in young adults with early-stage hypertension. The findings suggest that a misaligned Western-style meal consumed in the evening may result in prolonged sodium retention and storage that, while protective in the short term, could potentially have detrimental long-term effects on cardiovascular health. Supported by Sigma Xi Grant in Aid of Research, UM1TR004360 from the National Center for Advancing Translational Sciences, and APS, John F Perkins Career Enhancement Award. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.