Theanine maintains sleep quality in healthy young women by suppressing the increase in caffeine-induced wakefulness after sleep onset

Effect of a nutraceutical combination on sleep quality among people with impaired sleep: a randomised, placebo-controlled trial

In this randomised, placebo-controlled trial, adults with impaired sleep (Pittsburgh Sleep Quality Index ≥ 5) were randomly assigned using a minimization algorithm to receive a formulation containing L-theanine plus lemon balm, valerian, and saffron extracts, or placebo, during 6 weeks. Objective sleep quality parameters were measured using an actigraphy device. We enrolled and randomised 64 individuals, 31 from the active group and 27 from the placebo group completed the 6 week follow-up. Mean sleep efficiency remained unmodified in the active group, and increased by 3% in the placebo group, the between-group difference in the change was not statistically significant (p = 0.49). Total sleep time also improved more with placebo (13.0 vs. 1.33 min, p = 0.66). Time wake after sleep onset (WASO) decreased more in the active group (4.6% vs. 2.4%), but the difference was not significant (p = 0.33). Mean PSQI decreased by 3.11 points (32.3%) in the active group, and by 3.86 points (39.5%) in the placebo group (p = 0.41). SF-36 increased more with placebo (+ 18.3 in active, + 32.1 in placebo, p = 0.68). Salivary cortisol remained unchanged in both groups. No serious adverse events were reported. Among adults with impaired sleep, a nutraceutical combination did not improve objective or subjective sleep parameters more than a placebo infusion.

A combined effect of fish-originated collagen peptides and caffeine on the cognitive function of sleep-deprived mice

Refreshing beverages, consumed worldwide, commonly take advantage of caffeine's impacts on attention and motor performance. However, excessive long-term caffeine intake might disturb sleep/wake rhythms and exacerbate daily anxiety. Fish-originated collagen peptides (FCP) are of high nutrient value with stimulating, calming or relaxing effects, which could reduce the excitotoxicity of caffeine. This study aims to investigate two facets: (1) the combined effect of caffeine and FCP (namely C&F) on the cognitive function of sleep-deprived mice by different administration strategies with dose dependence (low and high dose) or time dependence (intervention in a day and prevention for a week); (2) the potential "microbiota-gut-brain" mechanism by which C&F improves sleep deprivation (SD)-induced cognitive impairments. Here, C57BL/6 mice were administered caffeine (10 or 20 mg per kg per bw) combined with FCP (100 or 200 mg per kg per bw) and were then subjected to 48 h SD. The open-field and Morris water maze tests were performed to evaluate the cognitive function and spatial learning capacities of mice. Our results indicated that the cognitive impairments of SD mice were significantly relieved to a different degree by treating C&F in a dose- and time-dependent manner. The pathological observation of the hippocampus indicated both intervention (time of a day) and prevention (time of a week) of the C&F protected brain tissue from SD-induced injuries. The accumulated pro-inflammatory neurometabolites and factors were significantly inhibited by C&F via the hypothalamus-hippocampal circuit. Furthermore, 16S rDNA analysis of colonic contents showed that the level of Lactobacillus murinus was significantly upregulated and that of Clostridia_UCG-014 was suppressed in the C&F group. The receiver operating characteristic (ROC) curve of Lactobacillus murinus indicated a certain diagnostic utility to distinguish C&F intervention (AUC = 0.52) or prevention (AUC = 0.68). Pathways of ko04622 (immune system) and ko00472 (metabolism processes) were significantly regulated by C&F in a time-dependent manner. Based on PICRUSt2 algorithm analysis, C&F might potentially regulate gut microbial functions through several metabolic pathways, including the RIG-I-like receptor signaling pathway and limonene and pinene degradation. In conclusion, C&F plays a key role in brain function and behavior, which could synergistically relieve cognitive impairments via the microbiota-gut-brain axis.