The Association Between Tea Consumption Timing and Kidney Function: Insights From a National Survey

Tea consumption has garnered significant attention due to its rich polyphenolic compounds and associated health benefits. However, existing research primarily focuses on the quantity of tea intake, while studies examining tea consumption timing remain limited. Given the circadian rhythm of kidney function and its metabolic implications, this study investigated the association between tea consumption timing, estimated glomerular filtration rate (eGFR), and chronic kidney disease (CKD) risk. Based on NHANES data from 2005 to 2018, 40,496 participants were included. Participants were grouped into high, medium, low, and non-tea intake groups. Additionally, tea consumption timing was categorized into four periods: dawn to noon, noon to afternoon, afternoon to night, and night to dawn. Multivariate regression models and restricted cubic spline models were employed to evaluate the associations between tea consumption timing, intake levels, and eGFR. Tea consumption timing showed a significant time-dependent association with eGFR levels. After adjusting for confounders, dawn-to-noon tea consumption demonstrated the strongest positive association with higher eGFR (3.18 mL/min/1.73 m², p < 0.001), followed by noon to afternoon (1.12, p < 0.001) and afternoon to night (0.71, p < 0.01). Stratified analyses revealed that daytime tea consumption was significantly associated with higher eGFR levels in middle-aged and older groups, whereas nighttime tea consumption in the younger group showed a slight adverse association. Analyses by tea type showed consistently positive associations for black tea, while green and other teas showed more variable results. This study underscores the significant association of tea consumption timing on kidney function, with the strongest associations observed during the dawn-to-noon period. Given the cross-sectional design of this study, only associations were identified; thus, future longitudinal studies are necessary to confirm these findings. Adjusting tea timing may be a potential dietary consideration for CKD prevention, but further studies are warranted.