The study is said to be the first to investigate how the combination of these specific herbal ingredients may influence cognitive performance, and brain activation of the prefrontal cortex (PFC) using functional near-infrared spectroscopy (fNIRS).
“Importantly, the results show clearly that the combination can modulate brain activation and cognitive task performance, and show reduced activation of the PFC related to effortful mental demand, reflecting increased neural efficiency concomitant with improved cognitive performance,” wrote scientists from Central Queensland University (Australia), Deakin University (Australia), and Nanyang Technological University (Singapore) in Nutritional Neuroscience.
The need for more research
Being the first study of its kind the researchers said the conclusions should be interpreted with some caution, and called for additional studies to replicate the findings.
“Whilst there may be different mechanisms of action for each substance in the combination of extracts, considering an underlying mechanism that might influence specific brain regions may be more useful,” they wrote. “Further, comparing dose, time of testing and age of healthy adults in future research could then determine potential ‘peak’ times and dose for acute beneficial effects utilising fNIRS as a sensitive measure to qualify the brain regions benefiting from consumption in more detail.
“Chronic intake studies would also be useful to determine whether there are any sustained long-term gains for performance and brain activation.”
Led by Central Queensland University’s Dr Talitha Best, the researchers recruited 40 healthy adults aged between 18–60 to participate in their randomized, double-blind, placebo-controlled, between-group study. Volunteers were randomly assigned to receive either two tablets of the multi-herb combination or placebo.
The active supplement was formulated using commercially available extracts of Bacopa monnieri (Bacognize from Verdure Sciences at a dose of 150 mg per tablet), American ginseng Panax quinquefolieus (Cereboost by Naturex at a dose of 50 mg per tablet) and whole coffee fruit extract (Neurofactor from FutureCeuticals at a dose of 50 mg per tablet).
The participants had their working memory and attention tested at the start of the study and again 45 minutes after ingesting the active supplement or placebo. During the cognitive testing, fNIS was used to continuously monitor changes in hemodynamic response in the prefrontal cortex.
Significant improvements in performance on the working memory task in terms of accuracy and response time were reported following consumption of the active supplement, compared to placebo, said the researchers.
The fNIS data showed a reduction of activation of the prefrontal cortex related to effortful mental demand, “reflecting increased neural efficiency concomitant with improved cognitive performance”, said the researchers.
Dr Best and her co-workers said that future studies should narrow the age range of participants to better examine how cognitive performance relates to cognitive aging, noting that middle-aged adults may experience more pronounced effects.
“The potential synergistic effects of polyphenolic compounds on neurocognitive function and fNIRS use in nutritional intervention studies, poses a significant increase in the capacity to understand the effects of dietary compounds on the brain,” they concluded.
Source: Nutritional Neuroscience
Published online ahead of print, doi: 10.1080/1028415X.2019.1690288
“Acute effects of combined Bacopa, American ginseng and whole coffee fruit on working memory and cerebral haemodynamic response of the prefrontal cortex: a double-blind, placebo-controlled study”
Authors: T. Best et al.