The 12-week double-blind, placebo-controlled trial, conducted by researchers from the University of Tsukuba and Japan Society for the Promotion of Sciences, involved 108 adults aged 65 and older who were independently mobile, did not suffer from dementia, and had no need for long-term care service.
To compare the effect of NMN intake at different times, they were each supplemented with 250 mg of NMN daily, either between waking up and noon, or between 6 PM and bedtime. Based on this, they were divided into four groups: two taking NMN either in the morning or evening, and two taking a placebo in the same periods.
A questionnaire was used to determine participants’ level of fatigue, while their limb function was evaluated with a series of physical performance tests. The participants
Better sleep, better function
The researchers found that NMN intake in the afternoon was the most effective in enhancing lower limb function, and effective in reducing drowsiness in those experiencing fatigue. They stated that this study was “the first to demonstrate the effects of the time-dependent intake of NMN on older adults”, and lined up with previous observations that fatigue typically “occurs more frequently in the afternoon when most daily activities end in a day”.
The participants who ingested NMN in the evening “showed significant improvement in sleep quality with a significant reduction in drowsiness, which may further improve physical performance”, though the researchers noted that it was “necessary to further verify the effect of NMN intake on sleep, as evaluated by objective measures in the future”.
At the same time, the researchers acknowledged the study’s limitations — namely, a daily diet containing NMN was not controlled, and a survey on daily nutrient intake was not conducted. As such, the study could not determine if the participants’ daily diet affected the effectiveness of their NMN intake. However, the amount of NMN in daily food such as fruits, vegetables, meat and seafood is “less than 1.8 mg per 100 g of food consumed”.
A placebo effect on drowsiness and sleep disturbance scores was also observed in the study. The research paper stated that though both researchers and participants were kept double blind until the end of the experiment, “participants might have perceived the placebo as NMN, which could be the reason for the observed placebo effects and the non-significant interaction between the four groups”.
Indications for future studies and supplementation
The researchers concluded that in future studies, it would be “necessary to conduct a survey on nutrient intake in daily life and additional analyses to examine the double effect”. They also mentioned NMN supplements to combat ageing had been launched on the market of late, but still maintained the opinion that “the effectiveness and safety of NMN should be clarified through further human clinical studies”.
“Effect of 12-Week Intake of Nicotinamide Mononucleotide on Sleep Quality, Fatigue, and Physical Performance in Older Japanese Adults: A Randomized, Double-Blind Placebo-Controlled Study”
Authors: Mijin Kim, et al.