We previously performed a 4 week interventional trial that suggested that continuous intake of rosemary extract improves the mood states, fatigue, and cognitive function of working generation healthy adult Japanese men. However, the severity of depression in participants in our previous study was relatively mild. Therefore, in the present study, a post-hoc analysis of our previous study was conducted, limited to participants whose total mood disturbance (TMD) scores, which indicate greater mood disturbance, were above the median at baseline, to evaluate whether rosemary extract was effective for individuals with poor mental health. Following the intervention, the scores of TMD and “Confusion-Bewilderment” were significantly decreased (both p < 0.05), and scores of “Vigor-Activity” were significantly increased in the rosemary group (n = 8) compared with those in the control group (n = 13; p < 0.01). When comparing the scores from pre- and post-intervention, significant improvements in “Tension-Anxiety”, “Vigor-Activity”, “Fatigue on awakening”, “Daytime sleepiness”, and “Psychomotor speed” were observed in the rosemary group only (all p < 0.05). Based on these results, it was expected that rosemary extracts were effective for improving the mental energy and sleep quality of work-age men with poor mental health.

The natto containing high levels of gamma-polyglutamic acid (γ-PGA) was recently developed. We investigated the effect of γ-PGA-rich natto consumption on postprandial glycemic excursion in humans. A randomized crossover meal test study was performed on healthy volunteers aged 20–64 years using the following test meals: (1) white rice (WR), (2) low-γ-PGA natto meal (WR + low-γ-PGA natto), and (3) high-γ-PGA natto meal (WR + high-γ-PGA natto). Blood samples were obtained at each visit before and for 120 min after loading. The incremental area under the curve (IAUC) of blood glucose and insulin levels was calculated and compared among the test meals. The blood glucose’s IAUC at 0–120 min, the primary endpoint, was 20.1% and 15.4% lower for the high- and low-γ-PGA natto meal than for the WR, with a significant difference only between the high-γ-PGA natto meal and WR (p < 0.05). The blood glucose’s IAUC at 0–15, 0–30, and 0–45 min was lower for the high-γ-PGA natto meal than for the low-γ-PGA natto meal (all p < 0.05). The possibility that high-γ-PGA natto might suppress blood glucose elevations in the early phase after eating is indicated.

We evaluated the suppressive effects of high-gamma-polyglutamic acid (γ-PGA) natto on postprandial blood glucose level and insulin response. After confirming the eligibility of candidates using a pre-selective test with packaged white rice, a meal loading test including low- or high-γ-PGA natto (with 57.6 mg (LPGA) and 439.6 mg (HPGA) of γ-PGA, respectively) was conducted in men aged 20 to 70 years (n = 29) and postmenopausal women aged ≤70 years (n = 7). On each examination day, blood samples were obtained after they fasted overnight and for 120 min after test meal loading. The primary outcome of this study was the difference between the measurements of the incremental area under the curve (IAUC) for blood glucose 0 to 30 min after loading of LPGA and HPGA meals. The IAUCs for blood glucose and insulin after the HPGA meal were lower than those after the LPGA meal within 45 min (0 to 15 and 0 to 30 min: p < 0.001, 0 to 45 min: p < 0.01) and 1 h (all p < 0.001) of loading, respectively. The suppressive effects of HPGA natto on postprandial glucose response in the early phase, which possibly relates to the risk of dysglycemia and cardiovascular disease, were clarified.

Although branched-chain amino acids (BCAA) are known to stimulate myofibrillar protein synthesis and affect insulin signaling and kynurenine metabolism (the latter being a metabolite of tryptophan associated with depression and dementia), the effects of BCAA supplementation on type 2 diabetes (T2D) are not clear. Therefore, a 24-week, prospective randomized open blinded-endpoint trial was conducted to evaluate the effects of supplementation of 8 g of BCAA or 7.5 g of soy protein on skeletal muscle and glycemic control as well as adverse events in elderly individuals with T2D. Thirty-six participants were randomly assigned to the BCAA group (n = 21) and the soy protein group (n = 15). Skeletal muscle mass and HbA1c, which were primary endpoints, did not change over time or differ between groups. However, knee extension muscle strength was significantly increased in the soy protein group and showed a tendency to increase in the BCAA group. Homeostasis model assessment for insulin resistance did not significantly change during the trial. Depressive symptoms were significantly improved in the BCAA group but the difference between groups was not significant. Results suggested that BCAA supplementation may not affect skeletal muscle mass and glycemic control and may improve depressive symptoms in elderly individuals with T2D.

β-(1,3/1,4)-glucan is a major component of cereal grains, such as oats and barley. In this study, we investigated the effects of cooked waxy barley, which contains β-(1,3/1,4)-glucan, on upper respiratory tract physical symptoms and mood status by performing a randomized, parallel-group, comparative trial. The primary outcome was assessed using the Wisconsin Upper Respiratory Symptom Survey-21 and Profile of Mood States second edition. Twenty-seven healthy Japanese adult participants were supplemented with 100 g of cooked waxy barley (containing 1.8 g of β-glucan) or 100 g of cooked white rice daily for 8 weeks. Participants receiving cooked waxy barley reported a reduction in cumulative days of sneezing (p < 0.05) and feeling tired (p < 0.0001) compared with the control group. After the intervention period, there were significantly less severe nasal symptoms, such as runny nose, plugged nose, and sneezing (p < 0.05), and a significantly greater reduction of the Tension-Anguish score (p < 0.05) in the barley group than in the control group. This study suggests that supplementation of cooked waxy barley containing β-(1,3/1,4)-glucan prevents or alleviates nasal upper respiratory tract symptoms and improves mood status. The findings of this study should be confirmed by double-blind trials with a larger number of participants.