The present study was aimed to clarify the effects of the time-dependent intake of NMN for 12 weeks on sleep quality, fatigue, and physical performance in Japanese older adults using a randomized, double-blind, placebo-controlled parallel-group study.
Deteriorating sleep quality and physical or mental fatigue in older adults leads to decreased quality of life and increased mortality rates.
This study investigated the effects of the time-dependent intake of Nicotinamide Mononucleotide (NMN) on sleep quality, fatigue, and physical performance in older adults.
This randomized, double-blind placebo-controlled study evaluated 108 participants divided into four groups (NMN_AM; antemeridian, NMN_PM; post meridian, Placebo_AM, Placebo_PM).
Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Fatigue was evaluated using the “Jikaku-sho shirabe” questionnaire.
Grip strength, 5-times sit-to-stand (5-STS), timed up and go, and the 5-m habitual walk was evaluated to assess the physical performance.
Overall, NMN intake in the afternoon effectively improved lower limb function and reduced drowsiness in older adults. These findings suggest the potential of NMN in preventing loss of physical performance and improving fatigue in older adults.
NMN (250 mg) or placebo was administered once a day for 12 weeks
Considering these findings this NMN study hypothesized that NMN intake has a more positive effect on sleep quality, fatigue, and physical performance than placebo in older adults.
There was no statistically significant interaction in sleep quality as assessed by the PSQI.
The interactions of fatigue with drowsiness were significant.
According to the post hoc analysis, the improvement in the drowsiness of Mid and Post was more significant than that of Pre in both NMN_PM and Placebo_PM groups
As shown in Table 4, a significant interaction was observed in 5-STS (p = 0.04). Significant main effects of time were observed in 5-STS.
An increase in NAD+ through NMN ingestion is expected to improve aging-related mitochondrial disorders, chronic inflammation, oxidative stress, DNA damage, and sirtuin inactivation [31,32], which may prevent the onset of age-related diseases and physical dysfunction.
Therefore, examination of the effects of the time-dependent intake of NMN was considered necessary, and two time zones (morning and afternoon) were set to investigate the optimal intake time to achieve the maximum efficiency of NMN absorption.
Although no human clinical study has reported that time-dependent intake of NMN leads to differences in its effects, activation of NAD+ has been reported to vary with time after NMN intake in mice.
This study showed a significant interaction between 5-STS and drowsiness after NMN intake for 12 weeks. The post hoc test and effect size revealed that 5-STS and drowsiness were significantly improved in the NMN_PM group. Collectively, this study suggests that NMN intake in the afternoon is more effective in improving lower limb function and reducing drowsiness in older adults, which could further benefit their physical and mental health.
The NMN study was conducted according to the guidelines of the Declaration of Helsinki and was approved by ethical committees of the University of Tsukuba (reference no. Tai 019-24).