Mediators of the effects of rice intake on health in individuals consuming a traditional Japanese diet centered on rice

Exploring the Therapeutic Potential of Gamma-Aminobutyric Acid in Stress and Depressive Disorders through the Gut-Brain Axis

Research conducted on individuals with depression reveals that major depressive disorders (MDDs) coincide with diminished levels of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) in the brain, as well as modifications in the subunit composition of the primary receptors (GABAA receptors) responsible for mediating GABAergic inhibition. Furthermore, there is substantial evidence supporting the significant role of GABA in regulating stress within the brain, which is a pivotal vulnerability factor in mood disorders. GABA is readily available and approved as a food supplement in many countries. Although there is substantial evidence indicating that orally ingested GABA may affect GABA receptors in peripheral tissues, there is comparatively less evidence supporting its direct action within the brain. Emerging evidence highlights that oral GABA intake may exert beneficial effects on the brain and psyche through the gut-brain axis. While GABA enjoys wide consumer acceptance in Eastern Asian markets, with many consumers reporting favorable effects on stress regulation, mood, and sleep, rigorous independent research is still largely lacking. Basic research, coupled with initial clinical findings, makes GABA an intriguing neuro-nutritional compound deserving of clinical studies in individuals with depression and other psychological problems.

Healthy Behavior and Environmental Behavior Correlate with Bicycle Commuting

Previous studies have identified that environmental awareness correlates with the choice of bicycle travel. However, few studies have considered the relationships with different types of healthy behaviors and environmental behaviors. This study examined the relationships between several healthy and environmental behaviors and the choice of bicycle commute using survey data. A total of 803 residents participated in this questionnaire survey. Using factor analysis, we constructed latent factors of healthy behaviors and environmental behaviors. Using a binary logistic regression model, we examined the relationship between latent factors and cycling usage, controlling for demographic characteristics. Factor analysis revealed three latent factors of healthy behaviors: “healthy diet”, “avoiding tobacco or overdrinking”, and “physical activity”. The latent factors of environmental behaviors were as follows: “household behavior” and “purchasing behavior”. The results showed that “avoiding tobacco or overdrinking”, “physical activity” and “purchasing behavior” correlated positively with bicycle commuting. Differences were also observed in relation to demographic characteristics.

Changes in the association between the traditional Japanese diet score and suicide rates over 26 years: A global comparative study

BACKGROUND

This study examined the global association between the Traditional Japanese Diet Score and suicide rate.

METHODS

Average food supply and energy supply by country were obtained from the Food and Agriculture Organization of the United Nations Statistics Division database (FAOSTAT). Traditional Japanese Diet Score (TJDS) was calculated from food group classifications. Age-standardized suicide rates per 100,000 people by country were obtained from the Global Burden of Disease 2017 database. The 26-year associations between TJDS and suicide rates were examined controlling for covariates using a mixed-effects model in 138 countries with populations of 1 million or greater.

RESULTS

A significant negative association was found in the analysis of the relationship between TJDS and the prevalence of suicide [β (se) = -0.126 (0.031), p < 0.001]. The interaction term between TJDS and year was also significant [β (se) = -0.011 (0.003), p < 0.001]. The change in the effect of TJDS on suicide rates by year was examined. The effect of TJDS was not significant from 1991 to 1999 but became significant after 2000; the slope of the TJDS to suicide rate in 2017 was -0.270 (95% confidence interval -0.382, -0.169, p < 0.001).

LIMITATIONS

This was a national ecological study and did not consider individual differences in sex, age, and lifestyle.

CONCLUSIONS

TJDS may be is a protective factor for depression, which may prevent suicide. The association between TJDS and suicide rates became stronger over time and was inversely associated with suicide rates after 2000.

Effect of the Intake of Brown Rice for Six Months on the Cognitive Function in Healthy Elderly Persons: A Study Protocol for a Pilot, Non-Randomized Controlled Trial

The nutritional components of brown rice have been reported to be effective against diabetes mellitus. Recent animal studies have suggested that it is also effective in maintaining cognitive function. Therefore, in this study, we examined the effect of a brown rice diet on cognitive function in individuals aged over 60 years. The study participants were recruited from a pool of individuals aged ≥60 years who were using elderly care facilities. The participants were provided with four servings of brown or white rice per week for 6 months, and their cognitive function was measured before and after the intervention period. Prior to the intervention, participants tasted the white and brown rice to determine which type they would like to be offered over the 6-month period. Since rice is the staple food of the participants in this study, they were allowed to decide whether they wanted to eat white or brown rice.

A Real-World, Prospective, Non-interventional Study of Adults with T2D Switching to IDegAsp from Glargine U100 or U300 in Japan

INTRODUCTION

This real-world study investigated glycaemic control and quality of life (QoL) in insulin-experienced Japanese patients with type 2 diabetes (T2D) who switched to insulin degludec/insulin aspart (IDegAsp).

METHODS

This was a prospective, non-interventional, open-label, single-arm study. Eligible patients were adults (aged ≥ 20 years) with T2D, previously treated with insulin glargine 100 or 300 units/mL (glargine U100/U300) with or without prandial insulin, who switched to IDegAsp as part of routine practice. Change from baseline to end of study (EOS; 26 weeks after initiation or IDegAsp discontinuation) in the following endpoints was assessed by adjusted mixed models for repeated measures: glycated haemoglobin (HbA1c; primary endpoint), fasting plasma glucose (FPG), insulin dose and total Diabetes Therapy-Related Quality of Life (DTR-QoL) score. Non-severe hypoglycaemia was assessed in the 4-week period prior to initiating IDegAsp and in the 4-week period before EOS or discontinuation using negative binomial regression.

RESULTS

The full analysis set included 236 patients from 29 centres in Japan with mean (± SD) age 63.2 years (± 12.3), HbA1c 7.7% (± 1.0) and diabetes duration 14.9 (± 9.3) years. After 26 weeks with IDegAsp, HbA1c (estimated change - 0.1% [- 0.2; 0.0]_{95% confidence interval (CI)}, p = 0.3036) and FPG (- 7.5 mg/dL [- 23.5; 8.5]_{95% CI}, p = 0.3477) were maintained; there were significant reductions in basal and total insulin dose: estimated change of - 3.4 units/day [- 3.8; - 3.0]_{95% CI} and - 1.0 units/day [- 1.9; - 0.1]_{95% CI}, respectively (both p < 0.05). Non-severe hypoglycaemia rates were similar in the periods before and after initiating IDegAsp, while there was a significant improvement in total DTR-QoL score after 26 weeks with IDegAsp (p = 0.0012).

CONCLUSION

These real-world data suggest that switching to IDegAsp from glargine U100 or U300 was well tolerated in a Japanese population with T2D, with no new safety or tolerability signals, and associated with maintenance of glycaemic control and improved QoL.

TRIAL REGISTRATION

This study is registered at ClinicalTrials.gov: NCT03745157.

White Rice Consumption and Risk for Colorectal Cancer among Japanese Americans: The Multiethnic Cohort Study

BACKGROUND

White rice is a staple food for Japanese, a population at high risk for colorectal cancer (CRC). We investigated the association between white rice intake and CRC among Japanese Americans in the Multiethnic Cohort (MEC) study.

METHODS

The Multiethnic Cohort Study is a prospective study established in Hawaii and California in 1993-1996. Usual dietary intake was assessed by a validated quantitative food frequency questionnaire at baseline. Cox proportional hazards models were used to compute hazard ratios (HR) and 95% confidence intervals (CI) for quartiles of intake and to perform trend tests across sex-specific quartiles with adjustment for relevant confounders.

RESULTS

We identified 1,553 invasive CRC cases among 49,136 Japanese Americans (23,595 men and 25,541 women) during a mean follow-up of 19 years. White rice consumption was not associated with overall CRC incidence in men (p_-trend = 0.11) or women (p_-trend = 0.56). After excluding participants with a history of diabetes, the inverse associations were significant for CRC (p_-trend = 0.03, HR for quartile 4 (Q4) vs. 1 = 0.81; 95% CI: 0.64-1.03) and tumors of the distal colon (p_-trend = 0.006, HR for Q4 vs. Q1: 0.66; 0.44-0.99) among men but not women.

CONCLUSIONS

White rice consumption was not associated with an increased risk of overall CRC among Japanese Americans. An inverse association was observed with risk of CRC and distal colon cancer in men without a history of diabetes.

What is the scientific definition of the Japanese diet from the viewpoint of nutrition and health?

The Japanese people have enjoyed longevity for several decades, and Japanese dietary habits are considered to contribute to this longevity. The scientific definition of the Japanese diet, however, is not yet fully established. The Working Group 1 of the Healthy Diet Research Committee of the International Life Sciences Institute Japan reviewed the literature to collect definitions of the Japanese diet appearing in articles in the fields of diet, nutrition, foods, and human health. This report addresses the definitions and the questions raised by these definitions. Among 283 relevant articles identified, 116 were carefully screened and included in the analysis. In most of the articles, the authors self-defined the Japanese diet; some studies used a government-proposed definition. This review revealed no systematic approach to define the Japanese diet from the viewpoints of nutrition and health. Before conducting studies to determine whether the Japanese diet is healthy, it is important to address the question of what the Japanese diet is from the viewpoint of human nutrition rather than culinary culture.

Impact of a Rice-Centered Diet on the Quality of Sleep in Association with Reduced Oxidative Stress: A Randomized, Open, Parallel-Group Clinical Trial

Previously, we found that a Japanese diet was associated with psychological status, and a combination of rice and miso was related to mental and physical health. We hypothesized that the intake of a rice-based diet affected mental and physical health and aimed to investigate the consequences of a dietary intervention with rice. We conducted a randomized, open-label, parallel-group clinical trial that included 60 participants, who were randomly assigned to receive either rice-based meals or meals with other cereals for three daily meals over 2 months. The participants were surveyed for psychological status and biochemical changes. Sleep quality index scores showed significant improvement after the rice-based intervention. Additionally, blood oxidative stress levels were reduced in the rice-diet group compared with the no-rice-diet group. Although the molecular mechanisms should be investigated in detail, our findings suggest that controlling oxidative stress through the intake of a rice-centered diet may be key to improving sleep quality.

Rice bran extract supplement improves sleep efficiency and sleep onset in adults with sleep disturbance: A randomized, double-blind, placebo-controlled, polysomnographic study

We previously reported that rice bran extract supplement (RBS) administration to mice decreased sleep latency and induced non-rapid eye movement (NREM) sleep via inhibition of the histamine H₁ receptor. Based on this, we performed the first clinical trial to investigate whether RBS would be beneficial to subjects with disturbed sleep. We performed a randomized, double‐blinded, placebo‐controlled, 2-week study. Fifty subjects with sleep disturbance were enrolled and received either RBS (1,000 mg/day) or placebo. Polysomnography was performed, and Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale (ESS), and Fatigue Severity Scale were administered at the initiation and termination of the study. Compared with the placebo, RBS led to significant polysomnographic changes, including decreased sleep latency (adjusted, P = 0.047), increased total sleep time (P = 0.019), and improved sleep efficiency (P = 0.010). Additionally, the amount of stage 2 sleep significantly increased in the RBS group. When adjusted for caffeine intake, wakefulness after sleep onset, total wake time, and delta activity tended to decrease in the RBS group. RBS administration decreased ESS scores. There were no reported serious adverse events in both groups. RBS improved sleep in adults with sleep disturbance. Trial registration: WHO ICTRP, KCT0001893.