Effects of Food Containing Pine Bark Extract on Capillary Blood Flow: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study

Background: Capillary blood flow supplies oxygen and nutrients to tissues throughout the body and removes metabolic waste; however, it declines with unhealthy lifestyles and aging. Therefore, maintaining adequate capillary blood flow is important. In this study, we aimed to evaluate the effects of consuming food containing pine bark extract on capillary blood flow in healthy adults. Methods: A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate the effect of pine bark extract on capillary blood flow in healthy participants. Fifty healthy women aged 40 - 59 years who were troubled by cold sensitivity were enrolled and randomly assigned to two groups. The active food group consumed food containing pine bark extract (2.4 mg/day as procyanidins B1 and B3) for 8 weeks, whereas the placebo food group consumed food without pine bark extract for the same period. The primary outcome was capillary blood flow velocity. The secondary outcome was capillary congestion, which was evaluated by a physician using a visual analog scale (VAS) based on capillary images. Results: After 8 weeks, compared with the placebo food group, the active food group showed a significant increase in capillary blood flow velocity and a significant decrease in capillary congestion. No adverse events related to the test food were observed. Conclusions: Intake of food containing pine bark extract may improve capillary blood flow in healthy women troubled by cold sensitivity.