Ashwagandha boosts memory and mood in clinical trial

By Vijay Kumar MalesuReviewed by Susha Cheriyedath, M.Sc.Jun 10 2024

In a recent study published in the journal Nutrients, researchers in the United States evaluated the impact of acute and repeated Ashwagandha (Withania somnifera) (ASH) supplementation on cognitive function and mood markers.

Study: Acute and Repeated Ashwagandha Supplementation Improves Markers of Cognitive Function and Mood. Image Credit: Bankim Desai / Shutterstock

Background 

Due to its antioxidant, endocrine-influencing, and immunomodulatory properties, ASH has been used for over 3,000 years in Ayurvedic medicine to manage stress, anxiety, and inflammation. Known to reduce cognitive decline related to inflammation and neurodegeneration, it is bioavailable and crosses the blood-brain barrier, making it therapeutic for conditions like type 2 diabetes mellitus, mild cognitive impairment (MCI), and neurodegenerative diseases. While studies show cognitive benefits in both clinical and healthy populations, such as improved memory and reduced stress markers, further research is needed to fully understand its long-term effects and mechanisms, especially in diverse populations.

About the study 

In the present double-blind, placebo-controlled clinical trial, participants aged 18 to 60 were recruited through various channels and screened for eligibility. Sixty individuals were enrolled and randomly assigned to either the placebo (PLA) group or the ASH group, with one participant excluded for non-compliance. The study was registered with the International Standard Randomised Controlled Trial Number (ISRCTN) and approved by the Human Research Protection Program Review Board. 

Participants attended a familiarization and two testing sessions, completing cognitive function tests (COMPASS), Profile of Mood States (POMS) questionnaires, and blood sample collections. Pre-supplementation assessments were conducted, followed by random assignment to placebo (225 mg of Gum Arabic) or liposomal ASH (225 mg of NooGandha®), with post-supplementation testing an hour later. Daily supplementation continued for 30 days, with final assessments mirroring initial protocols.

Cognitive function was evaluated using COMPASS software, and mood states were assessed via POMS. Blood samples were analyzed for health markers, and side effect perceptions were recorded. Statistical analysis using SPSS software included repeated measures General Linear Model (GLM) analyses and chi-squared tests for side effect differences, with clinical significance determined by mean changes from baseline and effect sizes assessed through partial Eta squared values.

Study results 

Participant demographic data indicated an average age of 22.7 ± 7.4 years (range 18-49), a height of 166.8 ± 21.7 cm, a weight of 74.9 ± 16.5 kg, and a body mass index (BMI) of 26.2 ± 5.1 kg/m². Significant sex differences were observed in body weight (females 68.8 ± 16.6 kg, males 82.1 ± 13.5 kg, p = 0.001) and resting blood pressure (females 112.3 ± 9.2 mmHg, males 125.8 ± 9.9 mmHg, p < 0.001), but not in age, height, BMI, resting heart rate, or diastolic blood pressure.

Cognitive function assessments revealed various outcomes. The word recall test showed a significant time effect (p < 0.001, ηₚ² = 0.063) with improvements in recall and delayed recall attempts following ASH supplementation, while no significant differences were observed in the PLA group. The word recognition test also displayed a significant time effect (p = 0.008, ηₚ² = 0.076) with improved recognition accuracy and reaction time for the ASH group. In the choice reaction time test, ASH supplementation tended to maintain target identification accuracy, contrasting with a decline observed in the PLA group.

The picture recognition test indicated significant time effects (p = 0.006, ηₚ² = 0.077) with ASH supplementation enhancing correct and overall reaction times. Digit vigilance test results showed improvements in correct response reaction time for the ASH group after 30 days, with no significant changes in the PLA group. The Corsi Block test and Stroop Color-Word test revealed significant time effects without notable interaction effects, with ASH maintaining cognitive performance over time.

The POMS questionnaire results indicated significant time effects across various mood domains, with ASH supplementation reducing tension and fatigue levels significantly over 30 days. Markers of health and safety, assessed through blood cell counts and serum clinical markers, showed that ASH supplementation maintained or improved clinical blood profiles more favorably compared to the PLA group. Specifically, ASH increased High-Density Lipoprotein (HDL) cholesterol and decreased the HDL to total cholesterol ratio, with additional favorable changes in Blood Urea Nitrogen (BUN), total bilirubin, protein, and calcium levels.

Throughout the study, no significant differences were observed in the frequency or severity of side effects between the ASH and PLA groups. No participants withdrew due to perceived side effects, indicating good tolerability of ASH supplementation. 

Conclusions 

To summarize, ASH has antioxidant, anti-inflammatory, neuroprotective, endocrinological, and immune-modulatory properties that may enhance cognition. Clinical trials suggest it benefits individuals with bipolar disorder, MCI, and chronic stress and improves memory, reaction times, and well-being in healthy individuals. This study found that acute and 30-day liposomal ASH supplementation improved episodic memory, attention, vigilance, and executive function and reduced tension and fatigue. Potential mechanisms include adaptogenic effects, neurotransmission enhancement, and gamma-aminobutyric acid (GABA)ergic activity. No significant adverse effects were reported.