RCT: Ashwagandha root extract may improve memory and cognitive functions

Dietary supplements that address cognitive function​​ are increasingly in the limelight thanks to a growing aging population, as well as the gaming, tech, and fitness culture that’s making nootropics in vogue​​.

Ashwagandha root has been a part of the medicinal traditions of Ayurveda as a memory aid, wrote researchers of a new study published in the Journal of Dietary Supplements​. In this current study, the researchers conducted what they claimed to be the first trial that looked at “the clinical impact of ashwagandha on the cognitive deficits seen in mild cognitive impairment.”​

Participants: Selecting patients of mild cognitive impairment​

The study was conducted over eight weeks using a random-assignment, parallel-group, double-blind, placebo-controlled design. Clinical visits all took place at one center, with participants being selected from different outpatient clinics in the city of Pune, India, who sought treatment for mild cognitive impairment.

To be included in the study, participants had to be aged 35 or older, have subjective sumptoms of memory impairment, a previous diagnosis of early dementia or a score a certain amount in a mini-mental state examination, and the ability and willingness to provide informed consent.

Excluded from the study are participants with severe memory impairment, known neuropsychiatric conditions, persistent endocrine disorders, and chronic medical conditions such as uncontrolled hypertension or diabetes mellitus.

Throughout the study period, other than ashwagandha root extract for the supplement group, the use of nootropic agents or anticholinesterase drugs were prohibited.

Preparing and assigning the supplements​

The ashwagandha root extract used in this study was the branded KSM-66, donated by Los Angeles-based Ixoreal Biomed, delivered in capsule form containing 300 mg of the aqueous extract.

For the placebo, starch capsules were kept in a cloth-covered envelope containing ashwagandha root so that the odor of ashwagandha permeated to the placebo capsules. The 50 recruited participants were randomized and divided into two equal groups.

The treatment group took two 300 mg capsules with water daily for eight weeks. The control group took an identical dose of the placebo capsules. Participants were evaluated at baseline, and twice again at the fourth and eighth weeks.

Measuring protocols and outcomes​

Participants were assessed using standardized tests for several memory types: Immediate memory (the ability to remember a small amount of information over a few seconds), general memory (delayed recall of word lists, geometric designs, text, faces), working memory (capacity to store information received from eyes, ears, and other sense organs in the immediate term).

They were also assessed for visuospatial processing and response, executive function, attention, and speed of information processing.

Study outcomes revealed that the ashwagandha group fared significantly better than baseline and the placebo group participants in terms of immediate and general memory test scores. There was also a great uptick in executive function, sustained attention, and information-processing speed.

According to the researchers, this may be from ashwagandha’s sedative properties, which “may be indirectly involved in improving memory and cognition in human subjects, as stress, anxiety, and sleep disorders can affect normal cognitive function,” ​they wrote.

The small sample size was one drawback of the study, and the researchers recommend a follow-up that is longer and with a larger sample to “confirm the promising results of this study.”​

Source: Journal of Dietary Supplements

Published online ahead of print, http://dx.doi.org/10.1080/19390211.2017.1284970​

Efficacy and Safety of Ashwagandha (Withania somnifera (L.) Dunal) Root Extract in Improving Memory and Cognitive Functions

Authors: Dnyanraj Choudhary, et al.