In a study published within the journal Frontiers in Nutrition, researchers in the UK investigated the impact of the 90-day supplementation of a multi-ingredient herbal complement on the cognitive abilities and gut microbiota of elderly patients showing a subjective memory decline. They found that the intervention resulted in memory deficits within the participants but improved the speed of cognitive tasks, coinciding with a better concentration of tyrosine within the urine and reduced levels of three bacterial species within the gut.
Study: Chronic supplementation of a multi-ingredient herbal complement increases speed of cognitive task performance alongside changes within the urinary metabolism of dopamine and the gut microbiome in cognitively intact older adults experiencing subjective memory decline: a randomized, placebo controlled, parallel groups investigation. Image Credit: lupvaliu / Shutterstock
Background
Although the consequences of specific individual herbs on brain function have been investigated, there is proscribed research on the intake of combos of herbal compounds. Combination products are typically formulated to boost the consequences of individual ingredients through the potential synergy amongst all of the ingredients, which will not be evident when the compounds are taken in isolation.
Evidence suggests that phytochemicals reminiscent of phenolics, terpene, micro- and macro-nutrients, and polysaccharide groups may support brain function by potentially conferring neuroprotection, interacting with neurotransmitter systems, supporting metabolism, and mediating the communication within the gut-brain axis. Given the dearth of research on a mixture of those ingredients, researchers in the current study evaluated the effect of a multi-ingredient complement on the cognitive function, urinary metabolome, and gut microbiome of older adults experiencing a subjective memory decline.
Concerning the study
The current randomized, placebo-controlled, double-blind, parallel-group intervention trial was conducted for 90 days on 128 participants between 55–75 years of age. The participants self-reported an age-related memory decline in comparison with their 20s and were otherwise healthy.
The participants were randomized to receive two capsules of either the magnesium stearate (placebo) or the herbal complement named “Turmeric Brainwave” with their day by day breakfast. The complement was a mixture of ingredients, including Bacopa monnieri, turmeric, gotu kola leaf, reishi (full spectrum), rosemary, cardamom, green tea, holy basil, and sea greens. The primary and last doses were taken on testing days within the laboratory, and the interim doses were taken by the participants at home.
The testing was done using a battery of cognitive tasks performed by participants once on day 1 (acute), twice on day 90 of the treatment (chronic), and once every week within the interim. The mental performance was assessed using a computerized, smartphone-based system (Cognim app) concerning speed and accuracy of attention, quality of memory, episodic memory, speed of memory, and overall speed and accuracy. The gut microbiome was analyzed by examining participants’ stool samples collected inside 18 hours of visiting the laboratory. Libraries of 16S-ribosomal ribonucleic acid (16S-rRNA) sequences were prepared and analyzed. Shannon diversity and rarefied bacterial richness were estimated, and statistical evaluation was performed using various tools. The urine metabolome was characterised using liquid chromatography of the urine samples collected prior to treatment within the laboratory.
Results and discussion
The post-dose compliance range of the intervention was found to be 84.6–112.1%. In comparison with baseline, placebo participants showed significantly higher accuracy of attention, quality of memory, episodic memory, speed of memory, and overall accuracy and speed. Moreover, memory deficits were observed even after 90 days of treatment with the multi-ingredient complement. Nonetheless, the treatment group showed a major improvement within the speed of cognitive task performance. Specifically, speed was found to be significantly higher in the next tasks: selection response time, numeric working memory, and Stroop tasks, with fewer errors within the rapid visual information processing task.
Within the gut microbiome evaluation, Shannon diversity was found to be greater within the treatment group than within the placebo group. Interestingly, although the gut bacterial abundance of the placebo group participants was impacted significantly by age, dietary habits, alcohol and caffeine consumption, and concomitant medication use, this effect was not observed within the treatment group. Moreover, the treatment group showed a major reduction within the abundance of three gut bacterial species, namely Anaerostipes spp., Sutterella, and Blautia, before and after the dose completion. A lower abundance of Sutterella was shown to coincide with reduced constipation and improved bowel movements within the treatment group.
The evaluation of the relative abundance of metabolites within the urine revealed increased tyrosine levels within the treatment group, indicating the role of dopamine within the observed increase in cognitive speed.
Conclusion
In conclusion, the study’s findings display that the multi-ingredient complement helped improve cognitive speed within the participants, modulated potentially by increased dopaminergic activity, while moreover improving their bowel experience. Nonetheless, the study is proscribed by the unequal randomization of participants into the treatment group before and after the coronavirus disease 2019 (COVID-19) pandemic. Further research is required to elucidate the unanticipated effects of the complement on memory and the potential utility of combination supplements in improving brain function in older adults.