Effects of Acute Ashwagandha Ingestion on Cognitive Function

International Journal of Environmental Research and Public Health

Sep 2022

DOI: 10.3390/ijerph191911852

Citations:33

Influential Citations:0

Interventional (Human) Studies

Enhanced Details

Methods

Randomized, double-blind, placebo-controlled, crossover trial; healthy men and women aged 18-59; no known cognitive deficits or major health issues (no wheat allergy, sleep disorders, chronic disease, uncontrolled migraines, high blood pressure, arrhythmias, anxiety disorders, or gastrointestinal disease); 15 participants randomized (7 placebo, 8 ASH); 13 completed; mean age 23.6 ± 4.7 years; weight 72.9 ± 18.9 kg; height 1.70 ± 0.12 m; BMI 24.8 ± 3.6.

Intervention

liposomal ashwagandha root and leaf extract (NooGandha), 400 mg per capsule; taken with 8 oz water; single-dose per session.

Results

Acute 400 mg liposomal ashwagandha root and leaf extract improved sustained attention and short-term/working memory in healthy young adults; faster reaction times in Go/No-Go tasks; no adverse effects reported; effects were domain-specific and not universal; supports potential cognitive-enhancing properties of ASH in healthy individuals.

Limitations

Small sample size; limited female representation; short-term, single-dose design; habitual diet and caffeine intake may confound results; considerable inter-individual variability; limited generalizability to other populations.

Abstract

Background: Ashwagandha (Withania somnifera) has been reported to decrease perceptions of stress, enhance mood, and improve cognitive function. However, it is currently unknown whether acute ashwagandha supplementation affects memory and cognitive function. This study evaluated the effects of acute ashwagandha extract ingestion on executive function. Materials and Methods: 13 healthy volunteers were administered the Berg–Wisconsin Card Sorting (BCST), Go/No-Go (GNG), Sternberg Task (STT), and Psychomotor Vigilance Task (PVTT) tests. Participants then ingested in a double-blind, placebo-controlled, and crossover manner 400 mg of a placebo (PLA) or ashwagandha (ASH) extract (NooGandha®, Specnova Inc., Boca Raton, FL, USA). Participants then performed cognitive function tests every hour for 6 h. After a 4-day washout period, volunteers repeated the experiment while receiving the remaining supplement. Data were analyzed by repeated measures General Linear Model multivariate and univariate statistics with body weight as a covariate. Results: Acute ASH supplementation increased STT-determined working memory as demonstrated by an improvement in 6 letter length, Present Reaction Time at 3 and 6 h. PVTT analysis revealed that ASH sustained attention by helping maintain reaction times, preventing mental fatigue, and remaining vigilant. Conversely, reaction times (at task 20, hour 6; overall, hour 3) increased with PLA. In the BCST, there was evidence that ASH increased the ability to recognize and ‘shift’ to a new rule compared with baseline. However, this was not seen when evaluating changes from baseline, suggesting that differences in baseline values influence results. In the GNG test, ASH ingestion promoted faster response times to respond correctly than PLA, indicating less metal fatigue. However, ASH did not affect accuracy compared to PLA, as both treatments decreased the percentage of correct answers. Conclusions: Acute supplementation with 400 mg of ashwagandha improved selected measures of executive function, helped sustain attention, and increased short-term/working memory. show less