Effects of lactotripeptide ingestion and physical activity intervention on the fatigue status of middle-aged and older adults: a randomized controlled trial

Abstract

This randomized controlled trial aimed to investigate the effects of eight weeks of lactotripeptide (LTP) ingestion, physical activity (PA) intervention, and combined intervention on the fatigue status of middle-aged and older adults. A total of 78 middle-aged and older adults (63 ± 8 years of age) were randomly assigned to four groups: placebo, LTP, placebo with PA intervention (placebo + PA), and LTP with PA intervention (LTP + PA). All participants ingested the placebo or LTP tablets daily (three tablets/day). The placebo + PA and LTP + PA groups participated in a weekly supervised exercise class and were instructed to increase their moderate- to vigorous-intensity PA at home. The visual analog scale, Brief Fatigue Inventory, Profile of Mood States second edition (POMS2), and Beck Depression Inventory second edition (BDI-II) were administered before and after the intervention. No significant interactions or main effects were observed between LTP ingestion and PA intervention on any of the fatigue scales. The main-effect analyses revealed that the PA intervention improved the total mood disturbance score of the POMS2 (F = 5.22, P = 0.03) and BDI-II score (F = 4.81, P = 0.03). After the post hoc paired comparisons, the total mood disturbance and BDI-II scores improved more with the combined intervention than with the PA intervention alone (percentage difference between the effect of combined intervention and PA intervention alone was 3.7% for total mood disturbance score and 13.7% for BDI-II score). The present study suggests that eight weeks of LTP ingestion and PA intervention did not have a significant effect on fatigue status. However, the PA intervention improved mood status and depressive symptoms, and these effects were enhanced by LTP ingestion.

Figure 1

The simple correlations between the changes in MVPA time and the changes in TMD (A) and BDI-II (B) scores. The change in MVPA time was calculated by subtracting the baseline MVPA time from the average MVPA time during the intervention period. Five participants were unable to assess baseline MVPA time, so the analysis was performed with 73 participants. Placebo placebo without physical activity intervention, LTP lactotripeptide without PA intervention, placebo + PA placebo with PA intervention, LTP + PA lactotripeptide with PA intervention, TMD total mood disturbance, BDI-II Beck Depression Inventory second edition.

Figure 2

Flow diagram of the participant’s progress through the 8-week randomized trial. Placebo placebo without physical activity intervention, LTP lactotripeptide without PA intervention, placebo + PA placebo with PA intervention, LTP + PA lactotripeptide with PA intervention.