Writing in the journal Nutrientsโ,ย researchers from the University of Auckland andย The Eastern Institute of Technologyย investigated the effects of supplementation with either a phytonutrient blend or placebo in 10 male cyclists following high-intensity interval exercise performed during ozone exposure.ย
โSerum BDNF levels increased following an acute bout of high-intensity exercise in an ozone-polluted environment,” they wrote.ย โIn addition, supplementation with an anthocyanin-rich supplement providing 4.3 mg/kg anthocyanins daily for 7 days resulted in significantly higher BDNF levels post-exercise compared to placebo.โย
The research was funded by the High Value Nutrition (HVN) Ko Ngฤ Kai Whai Painga National Science Challenge,ย a 10-year project to grow the science excellence and knowledge in support of food and beverage exports in Aotearoa, New Zealand.ย The supplement used in the study is manufactured by แพนrepa, a cognitive health company that markets brain drinks, shots, capsules and powders “designed and tested by neuroscientists”.
Polyphenols, exercise and ozone exposureโ
Tropospheric ozone, a component of urban air pollution, isย generated through photochemical reactionsโย involving hydrocarbons, nitrogen oxides and volatile organic compounds.
A highly reactive oxidizing molecule, it has adverse effects onย respiratoryโ, cardiovascular andย central nervous systemsโ, with links to neurological disorders such asย Alzheimer’s and Parkinson’s diseaseโ,ย cognitive impairmentโ,ย dementiaโย andย neuroinflammationโ.
Previous studiesโย have established the neurotoxic effects of ozone exposure, indicating interference with neural physiology, increased lipid peroxidation, reduced dopaminergic neurons, elevated inflammatory markers and accumulation of pathologic proteins.ย The hippocampus, which isย highly sensitive to oxidative effectsโ, is particularly affected byย acute ozone exposureโ.
BDNF is found throughout the brain andย abundantly in the hippocampusโย and plays a role inย neuronal growth, differentiation, neuronal survival, synaptic plasticityโย andย memory and learning processesโ.ย Previous research shows that it isย influenced by acute exerciseโย but appears to beย inhibited when exercise is performed in polluted airโ.
Polyphenols, including phenolic acids and compounds, have been associated withย neuroprotective effectsย andย improved cognitive functionโ, as well asย reduced respiratory inflammationโ. Theyย have also been reported to have aย beneficial effect on BDNF levelsโ.
However, the authors noted that controlled trials examining the acute effects of exercise on BDNF with ozone exposure in human subjects are lacking, particularly in the context of using a nutritional intervention to augment the effects.ย
โThis study therefore investigated whether supplementation with a functional blend of phytonutrients containing blackcurrant, L-theanine, and pine bark extract has a neuroprotective effect and affects cognitive processes following high-intensity interval exercise performed during ozone exposure,โ they wrote.
Study detailsโ
Participants completed a maximal incremental test and maximal effort 4 km time trial in ambient air.
They then completed two trials in an ozone-polluted environment (0.25 ppm) following seven days of supplementation with either the polyphenol (POLY) blend containing blackcurrant, L-theanine and pine bark extract or a placebo (PL).ย
Experimental trials consisted of a three-stage submaximal test followed by a 4 km time trial (TT).
Blood samples were drawn pre- and post-exercise and analyzed for BDNF, interleukin 6 (IL-6), interleukin 10 (IL-10) and tumor necrosis factor (TNF-ฮฑ).ย The Stroop test and serial subtraction task were performed before ozone exposure and again after the 4 km TT.
Serum BDNF increased post-exercise, and positive differences were observed post-exercise in the ozone POLY group relative to PL. In addition, plasma IL-6 increased post-exercise, and TNF-ฮฑ increased post-ozone exposure, however, there were no differences in Stroop or serial subtraction tasks pre- or post-exercise.
โA limitation of the study is the small sample size,” the authors noted. “We recommend that future studies be conducted to confirm the findings from the present study and that a larger sample size be recruited.โ
ย
Journal: Nutrientsโ
doi: 10.3390/nu16020233 โ
โThe Effects of Polyphenol Supplementation on BDNF, Cytokines and Cognition in Trained Male Cyclists following Acute Ozone Exposure during High-Intensity Cyclingโ
Authors: Lillian Morton et al.