Effekt av ashwaganda på minne och uppmärksamhet

[King Grub]

Chronic supplementation with ashwagandha (Withania somnifera root) reduces feelings of stress, improves mood and cognitive function. The potential benefits of acute ashwagandha supplementation on sustained attention, cognitive flexibility, and/or working memory are currently unknown. The purpose of this double-blind, placebo-controlled, crossover study was to examine the effect of acute ingestion of ashwagandha extract on executive function over time.

Materials and Methods

13 healthy male and female subjects (24±5 years, 170.0±11.8 cm, 72.9±19.3 kg, 24.8±3.7 kg/m2) were randomly assigned to consume 400mg of a proprietary ashwagandha extract (NooGandha®, Specnova Inc., FL) or placebo (PLA). Subjects completed four cognitive function tests (go no-go test, psychomotor vigilance task test, the Berg-Washington card sorting task, and the Sternberg task test), and then ingested a capsule of ashwagandha extract or PLA with 8 ounces of water. Participants repeated cognitive function tests 1, 2, 3, 4, 5, and 6 hours after ingestion of the supplement. After 7 days participants then repeated the experiment while consuming the alternative treatments. Data were analyzed by a General Linear Model multivariate and univariate analyses with repeated measures using body weight as a covariate.

Results

Acute supplementation with 400mg ashwagandha extract significantly increased short-term/working memory in one measure of the Sternberg test (letter length 6, present reaction time after 3 and 6 hours). As the list length increases, probe judgments become less accurate and slower, indicating increases in short-term memory and working memory demands. Ashwagandha resulted in sustained attention (maintained reaction times, prevention of mental fatigue) in the Vigilance Task Test, measuring a person's ability to remain heedfully vigilant. In contrast, placebo showed significantly reduced reactions times (task 20, hour 6; overall, hour 3). Ashwagandha increased the ability to both recognize and ‘shift' to a new rule (BCST) compared to baseline, however, change scores showed no beneficial effects, indicating that the difference in the pre-post analysis are due to differences in baseline values and not due to supplementation. Ashwagandha supplementation resulted in faster response times to correctly respond compared to PLA (shows less metal fatigue) in the go/no-go test. However, ashwagandha didn’t seem to alter accuracy relative to the placebo condition, as both treatments decreased the percentage of correct answers.

Conclusions

Acute supplementation with 400mg ashwagandha extract resulted in sustained attention and increased short-term/working memory.

Journal of the International Society of Sports Nutrition volume 17, Article number: 59 (2020). Acute ashwagandha supplementation improves cognitive function.