A daily 160 mg dose of a standardized extract of Ginkgo biloba for six weeks was associated with improvements of VO2max (maximal oxygen uptake) and blood antioxidant capacity, report scientists from the Jerzy Kukuczka Academy of Physical Education and the Poznan University of Physical Education.
Writing in Nutrients, the scientists also note that Ginkgo supplementation resulted in increased production of brain-derived neurotrophic factor (BDNF) during exercise. “BDNF is a molecular mediator of synaptic plasticity, hence, the BDNF signaling pathway is reduced in many neurodegenerative and psychiatric diseases,” they explained. Increasing BDNF levels, therefore, is considered beneficial.
The Polish researchers recruited 18 young active men and randomly assigned them to receive either the standardized Ginkgo biloba extract or placebo for six weeks.
The results showed that VO2max increased in both groups, but the greatest increases were measured in the Ginkgo group. However, no statistical significance was found between the groups, which may be due to the dose – previous studies have shown benefits from higher doses.
“Mahady [Nutr. Clin. Care, 2001, Vol. 4, pp. 140–147.] showed that recommended dose of [standardized Ginkgo biloba extract] to achieve beneficial effects is located in a dose between 40 and 60 mg of [Ginkgo biloba extract] 3–4 times daily,” wrote the researchers.
“In our study, subjects consumed 160 mg of [Ginkgo biloba extract] once a day for six weeks, which may explain only a marginal (6% vs. 1%) increase in the relative percentage VO2max change (baseline to intervention) scores in individuals receiving, respectively, the [Ginkgo biloba extract] or the placebo capsules.”
In addition, despite there being no significant increases in resting BDNF levels, the researchers did find that Ginkgo supplementation was associated with significant BDNF increases during exhaustive exercise.
Commenting on the potential mechanism(s) of action, the researchers note that the polyphenolic compounds in Ginkgo biloba may exert antioxidant effects by both directly scavenging reactive oxygen species (ROS), or by indirectly boosting the activities of antioxidant enzymes, such as glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD). The researchers did measure 20% increases in SOD activity in the Ginkgo group, compared to an 8% increase in the placebo group.
“Our results show that six weeks’ supplementation with a standardized Ginkgo biloba extract in physically active young men may provide some marginal improvements in their endurance performance expressed as VO2max and blood antioxidant capacity, as evidenced by specific biomarkers (SOD, GSH, UA, FRAP, and TBARS). Moreover, it may provide somewhat better neuroprotection through increased exercise-induced production of BDNF,” they concluded.
2017, 9(8), 803; doi:10.3390/nu9080803
“Effects of Six-Week Ginkgo biloba Supplementation on Aerobic Performance, Blood Pro/Antioxidant Balance, and Serum Brain-Derived Neurotrophic Factor in Physically Active Men”
Authors: E. Sadowska-Krepa et al.