Effects of Green Tea-Intake Timing on Glucose and Lipid Metabolism in Older Adults: An 8-Week Randomized Controlled...

Catechins in green tea have been reported to enhance glucose tolerance and lipid metabolism. However, the influence of chronic intake timing on these outcomes in older adults has not been fully elucidated. In this randomized controlled trial, we investigated the effects of green tea intake at different timings on glucose and lipid metabolism in older adults. Forty-five participants aged ≥ 65 years were randomly assigned to morning (n = 15), day (n = 15), or evening (n = 15) group. Participants consumed green tea daily for 8 weeks at specified times (0600-1100, 1100-1600, and 1600-2100 h for the morning, day, and evening groups, respectively). Glucose metabolism, lipid metabolism, and body composition were evaluated before and after the intervention. Blood glucose level, glycated hemoglobin level, body weight, and fat mass decreased with green tea intervention, while muscle mass increased across all groups (all p < 0.05). These findings indicate that individuals can expect similar improvements in glucose tolerance and body composition parameters from continuous green tea consumption regardless of intake timing in older adults. Trial Registration: University Hospital Medical Information Network (UMIN): UMIN000058708.