A Combination of Green Tea, Rhodiola, Magnesium, and B Vitamins Increases Electroencephalogram Theta Activity During Attentional Task Performance Under Conditions of Induced Social Stress

Abstract

Background: A combination of green tea, rhodiola and magnesium with B vitamins has previously been reported to significantly increase EEG resting state theta, attenuate subjective stress, anxiety and mood disturbance, and heighten subjective and autonomic arousal under acute psychosocial laboratory stress. Here we examine the capacity of green tea and rhodiola extract administered in combination or in isolation with magnesium and B vitamins to moderate spectral brain activity during attentional task performance under stress.

Materials and methods: One-hundred moderately stressed adults received oral supplementation of (i) Mg + B vitamins + green tea + rhodiola; (ii) Mg + B vitamins + rhodiola; (iii) Mg + B vitamins + green tea; or (iv) placebo, in a double-blind, randomised, placebo-controlled, parallel-group design (Clinicaltrials.gov: NCT03262376; 25/0817). Participants completed an attention switching and emotionally threatening attentional bias task after stress induction (Trier Social Stress Test). Spectral alpha and theta brain activity and event related potentials (ERPs) were recorded during cognitive task performance by electroencephalogram (EEG; BioSemi ActiveTwo 64 channel).

Results: The combined treatment of Mg + B vitamins + green tea + rhodiola significantly increased frontal midline theta vs. placebo and rhodiola in isolation during the attention switching task, specifically in anticipation of a change in task performance parameter. The combined treatment also significantly increased contralateral theta activation in relation to viewing emotionally threatening images in the left (vs. placebo and rhodiola in isolation) and right parietal (vs. placebo) regions. Further, this treatment demonstrated significantly heightened ipsilateral left parietal theta activation in relation to viewing emotionally threatening images. The combined treatment attenuated a decrease in alpha power during the attentional bias task evident in comparator treatments, but this did not reach significance. No significant effects of treatments on behavioural performance or ERP were found.

Conclusion: The combination of Mg + B vitamins + green tea + rhodiola increased spectral theta brain activity during the execution of two attentional tasks suggestive of a potential to increase attentional capacity under conditions of stress. Further examination of these ingredients in relation to attentional performance under stress is warranted to ascertain if functional benefits suggested by theta activation can be shown behaviourally.

Keywords: EEG; green tea; magnesium; rhodiola; stress.

Conflict of interest statement

LD has received consultancy and honoraria for work in the area of stress from Sanofi. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2022 Boyle, Dye, Lawton and Billington.

Figures

FIGURE 1

Attention switching task stimulus configuration [adapted with permission from Wylie et al. (7)] showing seven consecutive trials/EEG epochs.

FIGURE 2

Attentional bias task stimulus configuration showing two consecutive trials and EEG epoch.

FIGURE 3

Procedural timeline.

FIGURE 4

(A) Map of t-statistic comparison of oscillatory theta band activity during attention switching task in COMBINED vs. PLACEBO treatments (positive values indicate COMBINED > PLACEBO in comparison). A priori defined ROI midline frontal electrodes shown in map by . (B) Mean averaged ROI (SEM) frontal midline theta for each attention switching trial by treatment.

FIGURE 5

T-statistic map of alpha band power differences between COMBINED and PLACEBO treatments during presentation of emotionally threatening images shown in the (A) LEFT and (B) RIGHT visual fields. Values > 0 indicate COMBINED treatment alpha values are higher than PLACEBO treatment. Significant electrodes (p < 0.05) marked with an x. Each figure depicts a series of T-tests along the time course of the presentation of the images (0.5–1.05 s, in 0.1 s steps, 0.25 s sample widths).

FIGURE 6

Central figure: T-statistics maps of alpha difference between COMBINED and PLACEBO treatments 0.5–0.75 s after presentation of the images, distinguished by left and right emotionally threatening image presentation. Positive values in maps indicate COMBINED > PLACEBO. ROI electrodes symbols shown on maps and in respective summary bar charts. (A–D) Ipsilateral and contralateral frontal a priori defined ROI alpha band power when emotionally threatening image shown on left and right. (E–H) Ipsilateral and contralateral centro-parietal a priori defined ROI alpha band power when emotionally threatening image shown on left and right.

FIGURE 7

Theta band power differences between COMBINED and PLACEBO treatments during presentation of emotionally threatening and neutral images when stress images shown in (A) LEFT and (B) RIGHT visual fields. Values > 0 indicate COMBINED treatment theta values are higher than PLACEBO treatment. Significant electrodes (p < 0.05) marked with an x. Each figure depicts a series of T-tests along the time course of the presentation of the images (0.5–1.05 s, in 0.1 s steps, 0.25 s sample widths).

FIGURE 8

Central figure: T-statistic maps of spectral theta activity difference between COMBINED and PLACEBO treatments 0.5–0.75 s after presentation of the images, distinguished by left and right emotionally threatening image presentation. Positive values in maps indicate COMBINED > PLACEBO. ROI electrodes symbols shown on maps and in respective summary bar chart. (A,B) Theta band activity in a priori defined ROI midline frontal region for left and right presented images. (C,D) RIGHT parietal a priori defined ROI theta activity when emotionally threatening image shown on left and right. (E,F) LEFT parietal a priori defined ROI theta activity when emotionally threatening image shown on left and right.

FIGURE 9

Attention switching task (A) mean accuracy and (B) RT (ms) by trial type and treatment, and (C) attentional bias task attentional congruency score (incongruent trials RT – congruent trials RT) by treatment.