Acute and Repeated Ashwagandha Supplementation Improves Markers of Cognitive Function and Mood

Abstract

Background: Ashwagandha has been reported to reduce stress and attenuate cognitive decline associated with inflammation and neurodegeneration in clinical populations. However, the effects as a potential nootropic nutrient in younger populations are unclear. This study examined the effects of liposomal ashwagandha supplementation on cognitive function, mood, and markers of health and safety in healthy young men and women.

Methods: 59 men and women (22.7 ± 7 yrs., 74.9 ± 16 kg, 26.2 ± 5 BMI) fasted for 12 h, donated a fasting blood sample, and were administered the COMPASS cognitive function test battery (Word Recall, Word recognition, Choice Reaction Time Task, Picture Recognition, Digit Vigilance Task, Corsi Block test, Stroop test) and profile of mood states (POMS). In a randomized and double-blind manner, participants were administered 225 mg of a placebo (Gum Arabic) or ashwagandha (Withania somnifera) root and leaf extract coated with a liposomal covering. After 60-min, participants repeated cognitive assessments. Participants continued supplementation (225 mg/d) for 30 days and then returned to the lab to repeat the experiment. Data were analyzed using a general linear model (GLM) univariate analysis with repeated measures and pairwise comparisons of mean changes from baseline with 95% confidence intervals (CI).

Results: Ashwagandha supplementation improved acute and/or 30-day measures of Word Recall (correct and recalled attempts), Choice Reaction Time (targets identified), Picture Recognition ("yes" correct responses, correct and overall reaction time), Digit Vigilance (correct reaction time), Stroop Color-Word (congruent words identified, reaction time), and POMS (tension and fatigue) from baseline more consistently with several differences observed between groups.

Conclusion: Results support contentions that ashwagandha supplementation (225 mg) may improve some measures of memory, attention, vigilance, attention, and executive function while decreasing perceptions of tension and fatigue in younger healthy individuals. Retrospectively registered clinical trial ISRCTN58680760.

Keywords: attention; cognition; executive function; memory; mood; nootropic; vigilance.

Figure 1

Consolidated Standards of Reporting Trials (CONSORT) flow chart for the ashwagandha (ASH) and placebo (PL) groups.

Figure 2

Testing timeline. RHR indicates resting heart rate, BP indicates resting blood pressure, and POMS represents Profile of Mood States inventory.

Figure 3

Word recall test results. † = p < 0.05 effect from baseline value while ‡ = p > 0.05 to p < 0.10 difference from baseline.

Figure 4

Word recognition test results. † = p < 0.05 difference from baseline value while ‡ = p > 0.05 to p < 0.10 difference from baseline.

Figure 5

Choice reaction test results. ⁑ = p > 0.05 to p < 0.10 difference between treatment groups. † = p < 0.05 difference from baseline value.

Figure 6

Picture recall test results. † = p < 0.05 difference from baseline value while ‡ = p > 0.05 to p < 0.10 difference from baseline.

Figure 7

Digit vigilance test results. * = p < 0.05 difference between treatment groups. † = p < 0.05 difference from baseline value while ‡ = p > 0.05 to p < 0.10 difference from baseline.

Figure 8

Corsi Block test results.

Figure 9

Stroop Color–Word test results. ⁑ = p < 0.05 difference between treatment groups. † = p < 0.05 difference from baseline value while ‡ = p > 0.05 to p < 0.10 difference from baseline.

Figure 10

Profile of Mood States results. * = p > 0.05 to p < 0.10 difference between treatment groups. † = p < 0.05 difference from baseline value while ‡ = p > 0.05 to p < 0.10 difference from baseline.