Green Tea Extract Concurrent with an Oral Nutritional Supplement Acutely Enhances Muscle Microvascular Blood Flow without Altering Leg Glucose Uptake in Healthy Older Adults

Din, Ushnah S. U.; Sian, Tanvir S.; Deane, Colleen S.; Smith, Ken; Gates, Amanda; Lund, Jonathan N.; Williams, John P.; Rueda, Ricardo; Pereira, Suzette L.; Atherton, Philip J.; Phillips, Bethan E.

Abstract

Postprandial macro-and microvascular blood flow and metabolic dysfunction manifest with advancing age, so vascular transmuting interventions are desirable. In this randomised, singleblind, placebo-controlled, crossover trial, we investigated the impact of the acute administration of green tea extract (GTE; containing ~500 mg epigallocatechin-3-gallate) versus placebo (CON), alongside an oral nutritional supplement (ONS), on muscle macro-and microvascular, cerebral macrovascular (via ultrasound) and leg glucose/insulin metabolic responses (via arterialised/venous blood samples) in twelve healthy older adults (42% male, 74 ± 1 y). GTE increased m. vastus lateralis microvascular blood volume (MBV) at 180 and 240 min after ONS (baseline: 1.0 vs. 180 min: 1.11 ± 0.02 vs. 240 min: 1.08 ± 0.04, both p < 0.005), with MBV significantly higher than CON at 180 min (p < 0.05). Neither the ONS nor the GTE impacted m. tibialis anterior perfusion (p > 0.05). Leg blood flow and vascular conductance increased, and vascular resistance decreased similarly in both conditions (p < 0.05). Small non-significant increases in brachial artery flow-mediated dilation were observed in the GTE only and middle cerebral artery blood flow did not change in response to GTE or CON (p > 0.05). Glucose uptake increased with the GTE only (0 min: 0.03 ± 0.01 vs. 35 min: 0.11 ± 0.02 mmol/min/leg, p = 0.007); however, glucose area under the curve and insulin kinetics were similar between conditions (p > 0.05). Acute GTE supplementation enhances MBV beyond the effects of an oral mixed meal, but this improved perfusion does not translate to increased leg muscle glucose uptake in healthy older adults.

Citation

Din, U. S. U., Sian, T. S., Deane, C. S., Smith, K., Gates, A., Lund, J. N., …Phillips, B. E. (2021). Green Tea Extract Concurrent with an Oral Nutritional Supplement Acutely Enhances Muscle Microvascular Blood Flow without Altering Leg Glucose Uptake in Healthy Older Adults. Nutrients, 13(11), Article 3895. https://doi.org/10.3390/nu13113895

• Journal Article Type: Article
• Acceptance Date: Oct 28, 2021
• Online Publication Date: Oct 29, 2021
• Publication Date: Nov 1, 2021
• Deposit Date: Nov 12, 2021
• Publicly Available Date: Nov 12, 2021
• Journal: Nutrients
• Electronic ISSN: 2072-6643
• Publisher: MDPI AG
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 11
• Article Number: 3895
• DOI: https://doi.org/10.3390/nu13113895
• Keywords: Food Science; Nutrition and Dietetics
• Public URL: https://nottingham-repository.worktribe.com/output/6681621
• Publisher URL: https://www.mdpi.com/2072-6643/13/11/3895