TY - JOUR
T1 - Dietary nitrate modulates cerebral blood flow parameters and cognitive performance in humans: A double-blind, placebo-controlled, crossover investigation
AU - Wightman, Emma
AU - Haskell, Crystal
AU - Thompson, Kevin
AU - Blackwell, James
AU - Winyard, Paul
AU - Forster, Joanne
AU - Jones, Andrew
AU - Kennedy, David
N1 - Crystal Haskell now known as Crystal Haskell-Ramsay Published online first - 31 May 2015
PY - 2015/10/1
Y1 - 2015/10/1
N2 - Nitrate derived from vegetables is consumed as part of a normal diet and is reduced endogenously via nitrite to nitric oxide. It has been shown to improve endothelial function, reduce blood pressure and the oxygen cost of sub-maximal exercise, and increase regional perfusion in the brain. The current study assessed the effects of dietary nitrate on cognitive performance and prefrontal cortex cerebral blood-flow (CBF) parameters in healthy adults. In this randomised, double-blind, placebo-controlled, parallel-groups study, 40 healthy adults received either placebo or 450. ml beetroot juice (~. 5.5. mmol nitrate). Following a 90. minute drink/absorption period, participants performed a selection of cognitive tasks that activate the frontal cortex for 54. min. Near-Infrared Spectroscopy (NIRS) was used to monitor CBF and hemodynamics, as indexed by concentration changes in oxygenated and deoxygenated-haemoglobin, in the frontal cortex throughout. The bioconversion of nitrate to nitrite was confirmed in plasma by ozone-based chemi-luminescence. Dietary nitrate modulated the hemodynamic response to task performance, with an initial increase in CBF at the start of the task period, followed by consistent reductions during the least demanding of the three tasks utilised. Cognitive performance was improved on the serial 3s subtraction task. These results show that single doses of dietary nitrate can modulate the CBF response to task performance and potentially improve cognitive performance, and suggest one possible mechanism by which vegetable consumption may have beneficial effects on brain function.
AB - Nitrate derived from vegetables is consumed as part of a normal diet and is reduced endogenously via nitrite to nitric oxide. It has been shown to improve endothelial function, reduce blood pressure and the oxygen cost of sub-maximal exercise, and increase regional perfusion in the brain. The current study assessed the effects of dietary nitrate on cognitive performance and prefrontal cortex cerebral blood-flow (CBF) parameters in healthy adults. In this randomised, double-blind, placebo-controlled, parallel-groups study, 40 healthy adults received either placebo or 450. ml beetroot juice (~. 5.5. mmol nitrate). Following a 90. minute drink/absorption period, participants performed a selection of cognitive tasks that activate the frontal cortex for 54. min. Near-Infrared Spectroscopy (NIRS) was used to monitor CBF and hemodynamics, as indexed by concentration changes in oxygenated and deoxygenated-haemoglobin, in the frontal cortex throughout. The bioconversion of nitrate to nitrite was confirmed in plasma by ozone-based chemi-luminescence. Dietary nitrate modulated the hemodynamic response to task performance, with an initial increase in CBF at the start of the task period, followed by consistent reductions during the least demanding of the three tasks utilised. Cognitive performance was improved on the serial 3s subtraction task. These results show that single doses of dietary nitrate can modulate the CBF response to task performance and potentially improve cognitive performance, and suggest one possible mechanism by which vegetable consumption may have beneficial effects on brain function.
KW - beetroot
KW - near-infrared spectroscopy
KW - cerebal blood flow
KW - nitric oxide
KW - nitrite
KW - nitrate
KW - cognition
U2 - 10.1016/j.physbeh.2015.05.035
DO - 10.1016/j.physbeh.2015.05.035
M3 - Article
SN - 0031-9384
VL - 149
SP - 149
EP - 158
JO - Physiology and Behavior
JF - Physiology and Behavior
ER -