A Fraxinus excelsior L. seeds/fruits extract benefits glucose homeostasis and adiposity related markers in elderly overweight/obese subjects: A longitudinal, randomized, crossover, double-blind, placebo-controlled nutritional intervention study

The aim of this study was to investigate the potential benefits of an extract obtained from seeds/fruits of an Oleaceae (Fraxinus excelsior L.) on glucose homeostasis and associated metabolic markers in non-diabetic overweight/obese subjects.This study was performed in 22 participants (50–80 years-old; BMI 31.0kg/m2). The design was a longitudinal, randomized, crossover, double-blind, placebo-controlled 7-week nutritional intervention. The participants received daily 3 capsules each containing either 333mg of an extract from Fraxinus excelsior L. seeds (Glucevia®) or placebo capsules (control) in a random order for 3 weeks with 1 week of washout between treatments. Moreover, they followed a balanced covert energy-restricted diet (−15% energy). All variables were measured at the beginning and at the end of each period.Compared to baseline, the administration of 1g of Glucevia® for 3 weeks resulted in significantly lower incremental glucose area under the curve (−28.2%; p<0.01), and significantly lower 2h blood glucose values (−14%; p<0.01) following an oral glucose tolerance test. No significant changes were found in the control group (−7.9% AUC, −1.6% 2h blood glucose). Furthermore, significant differences were found between responses in the control and Glucevia® groups with respect to serum fructosamine and plasma glucagon levels (p<0.01 and p<0.05, respectively). Interestingly, administration of Glucevia® significantly increased the adiponectin:leptin ratio (p<0.05) and decreased fat mass (p<0.01) compared to control (p<0.05).The administration of an extract from Fraxinus excelsior L. seeds/fruits in combination with a moderate hypocaloric diet may be beneficial in metabolic disturbances linked to impaired glucose tolerance, obesity, insulin resistance and inflammatory status, specifically in older adults.