Associations between dietary diversity and high sensitive C-reactive protein among Japanese workers: findings of a cross-sectional and longitudinal study

PURPOSE

To clarify the association between dietary diversity and inflammatory status in Japanese workers.

METHODS

Of 1,460 men and women aged 20-64 years in 2010 (baseline), those who were followed-up at least once between 2011 and 2018 were included in this study; 1,433 participants and 745 participants were included in the cross-sectional and longitudinal analyses, respectively. Dietary intake was assessed using a food frequency questionnaire at baseline, and the dietary diversity score was determined using the Quantitative Index for Dietary Diversity (QUANTIDD). High-sensitivity C-reactive protein (hs-CRP) was taken to indicate inflammatory status at the baseline and follow-up surveys. In the cross-sectional analysis using baseline data, a generalized linear model was used to calculate adjusted means and 95% confidence intervals (CIs) for hs-CRP according to the QUANTIDD score. In the longitudinal analysis, generalized estimating equations were used to calculate the adjusted mean (95% CI) for hs-CRP in follow-up according to the QUANTIDD score at baseline.

RESULTS

In the cross-sectional analysis, the hs-CRP concentration in male participants was significantly lower in those who had a high QUANTIDD score (adjusted mean [95% CI]: 0.074 [0.009-0.140] mg/dL in the lower group vs. 0.038 [-0.029-0.105] mg/dL in the higher group, p-value = 0.034). In the longitudinal analysis, the hs-CRP concentration of male participants also tended to be lower in those with higher QUANTIDD scores (p-value = 0.103). In both the cross-sectional and longitudinal analyses in women, there was no significant difference between the lower and higher QUANTIDD score groups.

CONCLUSION

These findings suggest that, in male Japanese workers, higher dietary diversity might be important for maintaining a low inflammatory status.

Associations between dietary diversity and dyslipidemia among Japanese workers: cross-sectional study and longitudinal study findings

OBJECTIVE

The aim of this study was to determine the associations between dietary diversity and risk of dyslipidemia in Japanese workers.

METHODS

The cross-sectional study included 1399 participants aged 20-63 years and the longitudinal study included 751 participants aged 20-60 years in 2012-2013 (baseline) who participated at least once from 2013 to 2017 with cumulative participation times of 4.9 times. Dietary intake was assessed using a food frequency questionnaire, and dietary diversity score (DDS) was determined using the Quantitative Index for Dietary Diversity. Dyslipidemia was diagnosed when at least one of the following conditions was met: hypertriglyceridemia, high LDL-cholesterol, low HDL-cholesterol, high non-HDL-cholesterol, and a history of dyslipidemia. Multivariable logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for dyslipidemia with control of confounding factors in cross-sectional analysis. Generalized estimating equations were used for calculating the ORs (95% CI) for dyslipidemia in the follow-up period according to the DDS at baseline with control of confounding factors in longitudinal analysis.

RESULTS

Cross-sectional analysis showed that the highest DDS reduced the odds of dyslipidemia in men (OR [95% CI] in Tertile 3: 0.67 [0.48-0.95], p value = 0.023). In longitudinal analysis, a moderate DDS reduced the risk of dyslipidemia (OR [95% CI] in Tertile 2: 0.21 [0.07-0.60], p value = 0.003) in women.

CONCLUSIONS

The results of cross-sectional analysis in this study suggest that the higher diversity of diet might reduce the presence of dyslipidemia in men and the results of longitudinal analysis suggest that a moderate DDS might reduce the risk of dyslipidemia in women. Further studies are needed since the results of cross-sectional and longitudinal analyses in this study were inconsistent.

Soy isoflavone genistein attenuates the efficacy of immune checkpoint therapy in C57BL/6 mice inoculated with B16F1 melanoma and a high PD-L1 expression level reflects tumor resistance

Immune checkpoint therapy has been shown to be an effective therapy for many types of tumors. Much attention has been paid to the development of an effector target would be helpful for immune checkpoint therapy. Genistein has been shown to have an anti-tumor effect both in vitro and in vivo. In this study, we examined the effect of genistein on immune checkpoint blockade therapy against B16F1 melanoma tumors. Mice treated with genistein or anti-programmed death (PD)-1 antibody showed a significant decrease in tumor growth. However, treatment with genistein had no effect on or attenuated the efficacy of immune checkpoint therapy. The percentages of T cell receptor (TCR)β+CD4+ and TCRβ+CD8+ cells and the concentrations of interferon-γ and tumor necrosis factor-α in tumor tissue were not different among the experimental groups. A significant difference was also not found in microbe composition. Interestingly, a high expression level of PD-ligand (L)1 closely reflected the outcome of therapy by genistein or anti-PD-1 antibody. The study showed that a combination of genistein treatment does not improve the effect of immune blockade therapy. It also showed that a high PD-L1 expression level in tumors is a good prediction maker for the outcome of tumor therapy.

Changes in higher-level functional capacity during the COVID-19 pandemic among older adults living in Japan

OBJECTIVE

To evaluate change in higher-level functional capacity of older Japanese individuals during the COVID-19 pandemic.

METHODS

Four hundred older Japanese individuals completed an online questionnaire in early May 2021. Participants were asked retrospectively about their higher-level functional capacity and lifestyle before and during the COVID-19 pandemic. Higher-level functional capacity was determined as total score on the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC). Total TMIG-IC score ranges from 0 to 13. A decline in higher-level functional capacity was defined as a decrease in TMIG-IC score of more than 2 points during the COVID-19 pandemic. Changes in higher-level functional capacity during the COVID-19 pandemic were assessed by paired t-test and a general linear model.

RESULTS

Decreased TMIG-IC scores were found in 43 (21.5%) men and 61 (30.5%) women. Among those with higher-level functional capacity, scores for total TMIG-IC and Social Role decreased significantly in both sexes (all p<0.005).

CONCLUSION

The findings suggest an association of the COVID-19 pandemic with a decrease in higher-level functional capacity, especially in Social Role, among older adults living in Japan. J. Med. Invest. 71 : 66-74, February, 2024.

Validation of a dietary balance score in middle-aged and older community-dwelling Japanese

This study assessed the validity of dietary balance scores (DBSs) by investigating the association between DBSs and nutrient adequacy (NA) in two Japanese populations. The participants were 65 community-dwelling Japanese from Tokushima Prefecture and 2,330 community-dwelling Japanese from Aichi Prefecture. Based on food frequency questionnaires or 3-day dietary records, we obtained 18 food groups. The NA score integrates nine beneficial nutrients and two nutrients that should be limited. We calculated four different DBSs: DBS1 consisted of five food groups (score range:0?20), DBS2 consisted of nine food groups (score range:0?36), DBS3 consisted of eight food groups (score range:0?32), and DBS4 consisted of 10 food groups (score range:0?40). Both the Spearman rank correlation coefficient with NA and the area under the receiver operating characteristic curve (AUC-ROC) for the nine beneficial nutrients were then estimated to test the performance of each DBS in predicting nutrient intake. The results showed that DBS1 and DBS4 were positively correlated with NA, while the AUC-ROC showed that DBS4 could moderately discriminate individuals with adequate intake levels of all nine nutrients. These findings suggest DBSs (especially DBS4) are useful in assessing dietary balance in middle-aged and older community-dwelling Japanese. J. Med. Invest. 70 : 377-387, August, 2023.

Effects of polymethoxyflavonoids on T helper 17 cell differentiation in vitro and in vivo

We examined the effects of polymethoxyflavonoids (PMFs) on T helper (Th) 17 cell differentiation in vitro and in vivo. Five different PMFs including nobiletin (NOB), sudachitin (SUD), demethoxysudachitin, heptamethoxyflavone and natsudaidain were used for the in vitro study, and effects of those flavonoids on Th17 responses were investigated. NOB and heptamethoxyflavone significantly suppressed the proliferation response, but SUD, demethoxysudachitin and natsudaidain did not suppress the proliferation response. All of the five flavonoids decreased IL-17A production. Mice with experimentally induced autoimmune encephalomyelitis were used as an in vivo Th17 differentiation model. We focused on two flavonoids, NOB and SUD, and examined the effects of those flavonoids. NOB significantly suppressed Th17 cell proliferation and cytokine responses, but SUD only decreased proliferation responses. The results suggest that the suppressive effect of NOB on Th17 response in vivo is stronger than that of SUD. J. Med. Invest. 70 : 166-170, February, 2023.

Essential Oil of Citrus sudachi Suppresses T Cell Activation Both In Vitro and In Vivo

The essential oil of Citrus sudachi (sudachi oil) is extracted from the peel of sudachi, a citrus plant. We investigated the effect of sudachi oil on immune function in both in vitro antigen (Ag) induced lymphocyte activation and in vivo Ag-specific immune response. In the in vitro study, the proliferative activity of splenocytes upon Ag-specific and non-specific stimulation was suppressed by treatment with sudachi oil in a dose-dependent manner. In addition, the expression level of Ag-presentation-related molecules and their Ag-presenting function on dendritic cells were suppressed by sudachi oil. To examine how sudachi oil regulates an Ag-specific immune response in vivo, mice were immunized with ovalbumin and the immune response of the mice was investigated. Ag-specific proliferation response of splenocytes from mice treated with sudachi essential oil was significantly suppressed. The results indicate that sudachi oil suppresses T cell and dendritic cell functions in vitro and Ag-specific T cell induction in vivo.

Validity of dietary diversity assessed using short-form questionnaire among older Japanese community dwellers

The validity of dietary variety score (DVS) using a short-form questionnaire has not been investigated using dietary diversity based on a quantitative distribution of consumed foods in older Japanese. We examined the association between DVS and objective dietary diversity using a Quantitative Index for Dietary Diversity (QUANTIDD) based on the quantitative distribution of foods consumed by older Japanese community dwellers. The subjects were 65 older Japanese community dwellers aged 60?79 years. We used two kinds of scores for assessment of dietary diversity. At first, dietary diversity was determined using DVS calculated from answers to a questionnaire about frequencies of intake of 10 food groups. Second, dietary intake was assessed using a 3-day dietary record with photographs, and dietary diversity was determined using QUANTIDD. The relationships between DVS and QUANTIDD were assessed using partial correlation coefficients controlling for confounders. The correlation coefficient between DVS and QUANTIDD was moderate (r=0.212-0.458). After controlling for confounders, those correlation coefficient between DVS and QUANTIDD remained moderate. The findings suggest that there was a moderate relationship between DVS and QUANTIDD, and DVS using a short-form questionnaire may be useful for assessing dietary diversity in older Japanese community dwellers. J. Med. Invest. 69 : 31-37, February, 2022.

Dietary diversity and food choice motives during the COVID-19 pandemic among older Japanese: An Internet Panel Survey

BACKGROUND AND OBJECTIVES

We examined how food choice motives and dietary habits changed during the COVID-19 pandemic.

METHODS AND STUDY DESIGN

Four hundred elderly Japanese completed an online questionnaire in early May in 2021. Participants were retrospectively asked about their intake of food groups and food choice motives before and during the COVID-19 pandemic. Dietary diversity was determined using the dietary variety score calculated from the food frequency questionnaire with 10 food groups. The importance of each of the nine food choice motives for elderly people was assessed. Each scores ranged from 1 to 5. Changes in food choice motives and dietary behaviors during the COVID-19 pandemic were assessed using the paired t-test and a general linear model.

RESULTS

Among the food choice motives, scores for the importance of weight control, physical well-being and economical efficiency significantly increased in both sexes (all p<0.05). Dietary diversity score was lower during the COVID-19 pandemic than that before the pandemic in women (p=0.019), but there was no difference in men. In the multivariate adjustment model, physical well-being and economical efficiency were shown to have significant positive associations with the COVID-19 pandemic in women (p=0.034 and 0.009, respectively). In contrast, eating out was shown to have a significant inverse association with the COVID-19 pandemic in women (p=0.009).

CONCLUSIONS

The findings suggest that the COVID-19 pandemic was associated with an increase in some food choice motives and a decrease in the frequency of eating out among elderly female Japanese.

Intake of isoflavones reduces the risk of all-cause mortality in middle-aged Japanese

BACKGROUND/OBJECTIVES

To clarify the effects of intake of legumes and isoflavones on all-cause mortality in middle-aged and older Japanese.

SUBJECT/METHODS

The subjects were 2136 randomly chosen community-dwelling Japanese men and women aged 40-79 years who participated in a first-wave survey (1997-2000; baseline). The subjects were followed from baseline to December 31, 2017 (mean period of 16.6 ± 4.2 years). Intake of legumes, soybeans, and isoflavones at baseline was assessed using a 3-day dietary record with photographs. The relationships of intake amounts of legumes and isoflavones to mortality were assessed using Cox proportional hazards regression controlling for age, sex, education, employment, body mass index, smoking habits, medical histories, drinking, and energy intake.

RESULTS

There were 491 deaths during the follow-up period. We found inverse associations of the intake of total soy products and intake of each of the isoflavones with all-cause mortality (p for trend < 0.05) in subjects aged < 60 years: the multivariate-adjusted hazard ratios (95% confidence intervals) for all-cause mortality in the highest intake group (third tertile) of total soy products and total isoflavones were 0.32 (0.13-0.78) and 0.35 (0.17-0.73), respectively, compared with the reference group (first tertile). In contrast, there were no significant associations of intake amounts of legumes, soybeans, and isoflavones with all-cause mortality in subjects aged 60 years or older.

CONCLUSIONS

The findings suggest that a higher intake of isoflavones might decrease the risk of all-cause mortality, especially in middle-aged Japanese.

Nobiletin suppresses the development of experimental autoimmune encephalomyelitis mediated by modulation of T helper 17 cell differentiation

Multiple sclerosis is an organ-specific autoimmune disease that targets the myelin antigen in the central nervous system. Nobiletin is a dietary polymethoxylated flavonoid found in citrus fruits. In this study, we investigated how nobiletin affects the disease state and immune responses to myelin oligodendrocyte glycoprotein in experimental autoimmune encephalomyelitis mice. Nobiletin was administered orally from 14 days before immunization until the end of the experiment, and clinical scores were determined. The production levels of interleukin-17A and interferon-γ were measured in a culture supernatant of splenocytes stimulated with myelin oligodendrocyte glycoprotein. In addition, flow cytometric analysis was performed to examine the effect of nobiletin on T cell differentiation in vitro. Admin-istration of nobiletin significantly decreased the clinical score and interleukin-17A production in splenocytes. Furthermore, in vitro analysis showed that nobiletin significantly suppressed Th17 cell differentiation and interleukin-17A production in a dose-dependent manner. The results suggest that nobiletin attenuates experimental autoimmune encephalomyelitis severity through modulation of Th17 cell differentiation.

Associations of dietary diversity with allergic diseases in Japanese workers: a cross-sectional study

BACKGROUND AND OBJECTIVES

The aim of this study was to determine the associations of dietary diversity with prevalences of allergic diseases.

METHODS AND STUDY DESIGN

The participants were 1,317 men and women aged 20 to 63 years who were living in Tokushima Prefecture, Japan during the period 2012-2013. We obtained anthropometric data and information on lifestyle characteristics and current medical histories of allergic diseases using a self-administered questionnaire. Dietary intake was assessed using a food frequency questionnaire, and dietary diversity was determined using the Quantitative Index for Dietary Diversity (QUANTIDD). The ORs and 95% CIs for each of the allergic diseases with a 1 standard deviation (SD) increase in the QUANTIDD score were estimated, controlling for age, family history of allergic diseases, education, smoking, drinking, physical activity, energy intake and BMI.

RESULTS

Higher dietary diversity showed significant inverse dose-response relationships with allergic diseases and allergic rhinitis in women. Multivariate-adjusted ORs (95% CI) for allergic diseases and allergic rhinitis with 1 SD increase in the QUANTIDD score were 0.77 (95% CI: 0.60-0.98, p=0.037) and 0.69 (95% CI: 0.53-0.90, p=0.007), respectively, in women. There were no significant associations between dietary diversity and allergic diseases in men.

CONCLUSIONS

The results indicate that there is an inverse association between higher dietary diversity and allergic rhinitis in Japanese female workers.

Inactivation of Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli by UVA-LED irradiation system

The prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is increasing rapidly and spreading worldwide, particularly in Asia, compared to other regions. In the last ten years, in our hospital, in particular, there has been a < 30% increase. To prevent the spread of ESBL in hospitals and the community, the ultraviolet (UV) A-light-emitting diode (LED) irradiation device was used to inactivate ESBL-E. coli in human livestock and the environment. ESBL-E. coli and E. coli bacterial samples were collected from patients at Tokushima University Hospital (Tokushima City, Japan). The UVA-LED irradiation system had 365 nm single wavelength, and the current of the circuit was set to 0.23 or 0.50 A consistently. Results demonstrated that UVA-LED was useful for the inactivation of ESBL-E. coli and E. coli. The minimum energy dosage required to inactivate ESBL-E. coli and E. coli was 40.76 J/cm2 (45 min) in the first type of UVA-LED and 38.85 J/cm2 (5 min) in the second type. There were no significant differences between ESBL-E. coli and E. coli. The inactivation of ESBL-E. coli was dependent on energy. These findings suggest that UVA-LED with 365 nm single wavelength could be useful for surface decontamination in healthcare facilities. J. Med. Invest. 67 : 163-169, February, 2020.

Dietary diversity and characteristics of lifestyle and awareness of health in Japanese workers : a cross-sectional study

The aim of this study was to clarify the characteristics of lifestyle and health awareness according to dietary diversity in a Japanese worksite population. The participants were 1,312 men and women aged 20 to 63 years who were living in Tokushima Prefecture, Japan during the period 2012-2013. We obtained anthropometric data and information on lifestyle characteristics using a self-administered questionnaire. Dietary intake was assessed using a food frequency questionnaire, and dietary diversity was determined using the Quantitative Index for Dietary Diversity (QUANTIDD). The characteristics of lifestyle and health awareness according to quartiles of the QUANTIDD score were assessed using the chi-square test and a general linear model. The higher the QUANTIDD score was, the larger were the proportions of participants who knew the appropriate amount of dietary intake and participants who referred to nutritional component information when choosing and / or buying food. Among participants with higher QUANTIDD scores, the proportion of participants who considered their current diet was good was high in women, whereas the proportion of participants who wanted to improve their diet in the future was high in men. Those results indicate that higher dietary diversity was related to better characteristics of lifestyle and awareness of health. J. Med. Invest. 67 : 255-264, August, 2020.

Soy product and isoflavone intake associations with allergic diseases in Japanese workers: rhinitis, dermatitis and asthma

BACKGROUND AND OBJECTIVES

The aim of this study was to determine the associations of intake of soy products and isoflavones with allergic diseases.

METHODS AND STUDY DESIGN

We conducted a cross-sectional study in 1437 participants (aged 20-64 years) who were living in Tokushima Prefecture, Japan during the period 2010- 2011. We obtained anthropometric data and information on life style characteristics including dietary intake and current medical histories of allergic diseases using a structural self-administered questionnaire. Multiple logistic regression models were used to assess the associations of soy products and isoflavones with allergic diseases after controlling for age, family history of allergic diseases, smoking, drinking, physical activity, energy intake, BMI and dietary factors.

RESULTS

Intake of soy products showed significant inverse dose-response relationships with allergic rhinitis. The third quartile for soy products had an adjusted OR of 0.56 (95% CI: 0.35-0.91) compared to the reference group (first quartile), though intake of soy products showed no dose-response relationship with atopic dermatitis. Intake of soy isoflavones showed a significant inverse dose-response relationship with atopic dermatitis, though the association between intake of soy isoflavones and atopic dermatitis was U-shaped after adjustments for potential confounders. On the other hand, the associations between intake of soy isoflavones and other allergic diseases were not significant.

CONCLUSIONS

The results indicate that higher intake of soy products is associated with reduced risk of allergic rhinitis in Japanese workers. Furthermore, moderate intake amounts of soy products and soy isoflavones are associated with inverse risk of atopic dermatitis.

Nobiletin Enhances Induction of Antigen-Specific Immune Responses in BALB/c Mice Immunized with Ovalbumin

We examined the effect of nobiletin (5,6,7,8,3',4'-hexamethoxyflavone) on immune response in ovalbumin (OVA)-immunized mice. Treatment with nobiletin increased OVA-specific IL-4 and IL-10 production. In addition, mice that received nobiletin showed higher levels of OVA-specific IgE, IgG and IgG1 production than did control mice. The antibody response to the thymus-independent antigen 2,4,6-trinitrophenyl-Ficoll was not different in the control and nobiletin groups, suggesting that nobiletin does not directly stimulate antibody production. An in vitro study showed that treatment with nobiletin enhanced the ability of antigen presentation of bone marrow-derived dendritic cells. The in vivo and in vitro results indicate that nobiletin regulates immune function.

Sudachitin, polymethoxyflavone from Citrus sudachi, enhances antigen-specific cellular and humoral immune responses in BALB/c mice

Scdachitin is a polymethoxyflavone (5,7,4'-trihydroxy-6,8,3-trimethoxyflavone) that is found in the peel of Citrus sudachi. We examined the effect of sudachitin on immune response in ovalbumin-immunized BALB/c mice. Treatment with sudachitin increased ovalbumin-specific IL-4 and IL-10 productions. In addition, mice that received sudachitin showed higher levels of ovalbumin-specific IgE, IgG1 and IgG l production than did control mice. The antibody response to the thymus-independent antigen 2,4,6-trinitrophenyl Ficoll was not different in the control and sudachitin groups, suggesting that sudachitin does not directly stimulate antibody production. An in vitro study showed that treatment of sudachitin enhanced the ability of antigen presentation in bone marrow-derived dendritic cells. Furthermore, CD11c⁺ cells that had been treated with sudachitin showed increased expression of co-stimulatory molecules. The results indicate that sudachitin regulates immune function both in vivo and in vitro.

Soy food and isoflavone intake reduces the risk of cognitive impairment in elderly Japanese women

Data were derived from the National Institute for Longevity Sciences-Longitudinal Study of Aging. Subjects comprised 403 men and 373 women aged 60-81 years at baseline who participated in the follow-up study at least once. Bean, soy product and soy isoflavone intake was assessed using a 3-day dietary record at baseline. Cognitive function was assessed by the Mini-Mental State Examination (MMSE). MMSE scores of ≤23 were used to define cognitive impairment. The relationship between bean, soy product and soy isoflavone intake and cognitive impairment was assessed using a generalized estimating equation. Multivariate-adjusted odds ratios (95% confidence intervals) for cognitive impairment with a 1 s.d. increase in total bean, total soybean and total soy isoflavone intakes were 0.48 (0.28-0.81; p = 0.006), 0.51 (0.32-0.83; p = 0.007), and 0.55 (0.32-0.93; p = 0.026), respectively, in women. Total soybean and soy isoflavone intake might decrease the risk of cognitive impairment in elderly Japanese women.

Associations between intake of dietary fermented soy food and concentrations of inflammatory markers: a cross-sectional study in Japanese workers

Epidemiological investigations have shown that consumption of soybeans or soy foods reduces the risk of the development of cardiovascular disease, cancer and osteoporosis. The aim of this study was to determine the associations between different soy foods and inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, and IL-18, in Japanese workers. The cross-sectional study included 1,426 Japanese workers (1,053 men and 373 women) aged 20 to 64 years. Intake of 12 soy foods was estimated by a validated food frequency questionnaire. Associations of total soy foods, fermented soy food, non-fermented soy food, soy isoflavone with hs-CRP, IL-6, and IL-18 levels were examined by general linear model regression analysis. We found that total fermented soy food intake was inversely associated with multivariable-adjusted geometric concentration of IL-6 in men (Q1:1.03 pg/mL, Q5:0.94 pg /mL;P for trend = 0.031). Furthermore, it was shown that IL-6 concentrations were inversely associated with miso intake (β = -0.068;p = 0.034) and soy sauce intake in men (β = -0.074;p = 0.018). This study suggests that intake of total fermented soy food, miso and soy sauce be associated with IL-6 concentrations in Japanese men. J. Med. Invest. 65:74-80, February, 2018.

Inverse association between soy food consumption, especially fermented soy products intake and soy isoflavone, and arterial stiffness in Japanese men

Studies on the associations between soy food consumption and arterial stiffness are rare. The aim of the present study was to evaluate their associations in Japanese men. A total of 652 eligible men, aged 35-69 years, who underwent the measurement of brachial-ankle pulse wave velocity (baPWV) as an index of arterial stiffness were evaluated in this cross-sectional study. Information on their lifestyle characteristics, including dietary behavior, was obtained from a structured self-administered questionnaire. The frequency of total soy products as well as fermented and non-fermented soy products intakes was calculated, and the amounts of soy protein and soy isoflavone intakes were also estimated; these were then divided into tertiles and their associations with baPWV values were evaluated using general linear models. Higher frequency of fermented soy products intake was associated with decreased baPWV after adjusting for the multivariable covariates (P value for trend was 0.002, in Model 3). This association did not alter after further adjustment with a biomarker of systemic inflammation (serum high-sensitivity C-reactive protein (hs-CRP)) (P value for trend was 0.001, in Model 4). Total soy isoflavone consumption was also inversely associated with baPWV even after adjusting for multivariable covariates including serum hs-CRP (P value for trend was 0.043, in Model 4); however total soy protein consumption was not. These results demonstrated that greater consumption of soy food, especially fermented soy products and soy isoflavone was associated with reduced arterial stiffness, independent of systemic inflammation, in Japanese men.

Nutrient-Derived Dietary Patterns and Their Association With Metabolic Syndrome in a Japanese Population

Background

Nutrients have been proposed to be related to metabolic syndrome (MetS). The aims of this study were to identify dietary patterns that correlated with several nutrients using reduced rank regression (RRR) and to examine the association between extracted dietary patterns and prevalence of MetS in a Japanese population.

Methods

The study population comprised 1,092 Japanese men and women (35–69 years old) who had participated in the baseline survey of the Japan Multi-Institutional Collaborative Cohort Study in Tokushima Prefecture. Dietary patterns were derived with RRR using 46 food items as predictors and six established nutrients (potassium, calcium, vitamin D, vitamin C, insoluble dietary fiber, and carotene) as response variables. Associations between extracted dietary patterns and MetS were then examined with logistic regression models.

Results

Among the six dietary patterns, dietary pattern 1 (DP1) explained the largest proportion (60.1%) of variance in the six nutrients. Therefore, only DP1 was selected for further analysis. DP1 was characterized by high intake frequency of vegetables, fruits, fish and small fish, natto (fermented soybeans), and deep-fried tofu. After adjustment for potential confounders, significant inverse associations were found between DP1 score and MetS (odds ratio [OR] for each quartile: 1.00, 0.58, 0.60, 0.52; P_trend = 0.02); DP1 and high blood pressure (P_trend = 0.0002); and DP1 and high blood glucose (P_trend = 0.02).

Conclusion

A dietary pattern characterized by high intake of vegetables, fruits, fish and small fish, natto, and deep-fried tofu was associated with reduced prevalence of MetS in a Japanese population.

Dietary calcium intake is associated with serum high-sensitivity C-reactive protein level in the general Japanese population

The beneficial effects of dietary calcium intake on high-sensitivity C-reactive protein levels, a risk factor of cardiovascular disease, have not been fully elucidated. This study investigated the associations between dietary calcium intake and serum high-sensitivity C-reactive protein levels in the general Japanese population. We analyzed the data of 2,019 subjects (1,194 men and 825 women) aged 35 to 69 years in a cross-sectional study of the Japan Multi-Institutional Collaborative Cohort Study. Nutrients intake including calcium were estimated using a validated food-frequency questionnaire. Analysis using a general linear model revealed that dietary calcium intake was inversely associated with serum high-sensitivity C-reactive protein levels (p for trend <0.001) after adjustment for age, sex, research group, leisure-time physical activity, smoking habit, drinking habit, dietary intakes (energy, dietary fiber, saturated fatty acids and vitamin D) and menopausal status. The association was slightly attenuated after additional adjustment for body mass index; however, remained significant (p for trend = 0.008). There were no significant interactions between dietary calcium intakes and sex, body mass index, or vitamin D intake for high-sensitivity C-reactive protein levels. This study have demonstrated that dietary calcium intake was inversely associated with serum high-sensitivity C-reactive protein levels in the general population.

Extracts of citrus Sudachi peel attenuate body weight gain in C57BL/6 mice fed a high-fat diet

Citrus Sudachi is the special local product of Tokushima Prefecture, and over 98% of Sudachi consumed in Japan every year is produced in Tokushima Prefecture. In this study, we evaluated the function of sudachi peel extract (SPE) using an animal model of obesity. C57BL/6 mice were fed a high-fat diet containing 1% SPE powder. Treatment with SPE significantly decreased body weight compared to that of mice fed a high-fat diet. A significant difference in body weight was observed between the control and SPE groups from 7 weeks after the start of the experiment, the significant difference continued until the end of the 14-week experiment. Reduction of blood glucose levels following insulin administration in SPE-treated mice was grater than that in control mice. Determination of mRNA expression in adipose tissue showed that the expression level of TNF-α in the SPE group was significantly decreased compared to that on the control group. These results suggest that SPE potentially has the ability to attenuate body weight gain. J. Med. Invest. 64: 20-23, February, 2017.

Brazilian Green Propolis Promotes Weight Loss and Reduces Fat Accumulation in C57BL/6 Mice Fed A High-Fat Diet

Propolis is a bee product with various biological properties. C57BL/6 mice were fed a high-fat diet and treated with propolis for 14 weeks. Body weight in mice treated with 2% propolis was less than that in control mice from 3 weeks after the start of treatment until 14 weeks except for the 7th week. Mice treated with propolis showed significantly lower epididymal fat weight and subcutaneous fat weight. Infiltration of epididymal fat by macrophages and T cells was reduced in the propolis group. Supplementation of propolis increased feces weight and fat content in feces, suggesting that mechanisms of weight reduction by propolis partly include a laxative effect and inhibition of fat absorption.

Association between dietary patterns and serum adiponectin: a cross-sectional study in a Japanese population

The aim of this study was to evaluate the associations between dietary pattern, adiponectin and insulin resistance. The study population consisted of 612 men and women aged 35-69 years old who had participated in the baseline survey of Japan Multi-Institutional Collaborative Cohort (J-MICC) Study in Tokushima Prefecture. Diets and lifestyle related variables were assessed by questionnaires. Multiple regression analyses were used to analyse the relations between dietary patterns and high molecular weight (HMW) adiponectin. For further analysis, path analysis was used to test the hypothesised model of association between dietary pattern, serum adiponectin and insulin resistance. The result showed that higher score of bread and dairy pattern was directly associated with increased serum level of adiponectin in women, which was inversely related to homeostasis model assessment of insulin resistance (HOMA-IR). In conclusion, higher consumption of bread and dairy products, and low intake of rice may be associated with increased serum adiponectin in women.

Age-related Changes in Energy Intake and Weight in Community-dwelling Middle-aged and Elderly Japanese

OBJECTIVE

This study attempts to describe trends in energy intake and weight change over 12 years according to age at first participation in the study.

DESIGN

Prospective cohort study.

SETTING

The National Institute for Longevity Sciences - Longitudinal Study of Aging (NILS-LSA), a community-based study.

PARTICIPANTS

Participants included 922 men and 879 women who participated in the first study-wave (age 40-79 years) and also participated in at least one study-wave from the second to seventh study-wave. Each study-wave was conducted biennially. For individuals, the entire follow-up period was 12 years.

MEASUREMENTS

Energy intake was calculated from 3-day dietary records with photographs. Weight and height were measured under a fasting state. To estimate linear changes in energy intake and weight over 12 years according to age at first study-wave, we used the mixed-effects model.

RESULTS

Mean (SD) follow-up time and number of study-wave visits were 9.5 (3.7) years and 5.4 (1.8) times, respectively. The fixed effect of the interaction of age and time in energy intake and weight was statistically or marginally statistically significant both in men (p<0.01) and in women (p<0.06). In men, when energy intake was estimated according to age, the rate of decrease in energy intake increased from -6.8 to -33.8 kcal/year for ages 40-79 years. In women, the rate of decrease in energy intake slightly increased in older age groups (-9.1 to -16.7 kcal/year for ages 40-79 years). Weight increased in males in their 40s (0.07 kg/year from age 40) and started to decline by age 53. In women, weight started to decline around age 47 (-0.04 kg/year).

CONCLUSION

Twelve-year longitudinal data showed energy intake declined both in men and women in their 40s, and the rate of decrease increased in older males. Weight started to decline in men in their mid-50s and women in their late 40s. Further studies that focus on energy intake and weight reduction are needed to prevent weight loss or underweight in an increasingly aging society.

Vitamin A Deficiency Impairs Induction of Oral Tolerance in Mice

Oral tolerance is a phenomenon of induction of systemic unresponsiveness to antigens ingested by the oral route and loss of immune response. Studies have shown the importance of vitamin A in oral tolerance in vitro but not in an in vivo experimental model. Therefore, we carried out experiments to determine how vitamin A deficiency affects tolerance induction and the ability of mesenteric lymph node (MLN) CD11c(+) cells to induce regulatory T cells (Tregs). Immunological tolerance was induced by oral ovalbumin (OVA) administration in vitamin A-sufficient mice. OVA-specific antibody and cytokine production were significantly reduced. On the other hand, in vitamin A-deficient mice, both OVA-specific antibody and cytokine production were not suppressed by oral OVA administration. Regarding induction of Tregs, the conversion rate of Foxp3(+) cells from naïve CD4(+) cell by CD11c(+) cells was decreased in vitamin A-deficient mice. Our study indicates that vitamin A deficiency causes the breakdown of oral tolerance in vivo.

Inverse association between soya food consumption and insulin resistance in Japanese adults

OBJECTIVE

The purpose of the present study was to examine the association between soya food consumption and insulin resistance using baseline data of the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study in Tokushima, Japan.

DESIGN

This cross-sectional study included 1274 subjects, aged 34-70 years at baseline, living in Tokushima Prefecture between 2008 and 2013. Fasting blood samples were collected and information on lifestyle characteristics including soya food intake and medical history were obtained using a structured self-administered questionnaire. The homeostasis model assessment of insulin resistance (HOMA-IR) was measured and those with HOMA-IR ≥ 2.5 were defined as having insulin resistance. Multiple logistic regression models were used to analyse the association between soya product intake and the prevalence of insulin resistance.

SETTING

Rural communities located in Tokushima Prefecture, Japan, between 2008 and 2013.

SUBJECTS

A total of 1148 adults (565 men and 583 women), aged 34-70 years.

RESULTS

The frequency of intake of miso soup, total non-fried soya products and total soya products showed significant inverse dose-response relationships with insulin resistance, after adjustments for potential confounders. When soya product intake was calculated as soya protein and isoflavone, the odds ratios of insulin resistance decreased significantly as the estimated intake of soya protein increased. Furthermore, significant inverse dose-response relationships were observed for total non-fried soya products and total soya products, after adjustment for total vegetable or total fibre consumption.

CONCLUSIONS

The present results indicate that the intake of soya products and non-fried soya products is associated with reduced insulin resistance in the Japanese population.

Family history of stroke is potentially associated with arterial stiffness in the Japanese population

BACKGROUND

Studies on the association between family history of cardiovascular disease and arterial stiffness are rare.

AIMS

This study evaluated the possible relationship between family history of cardiovascular disease and arterial stiffness in the Japanese population, by measuring brachial-ankle pulse wave velocity (ba-PWV).

METHODS

A total of 1004 eligible subjects (664 men and 340 women) aged 35-69 years, who were enrolled in the baseline survey of a cohort study in Tokushima Prefecture (Japan) and who underwent ba-PWV measurement, were analysed. Information about their lifestyle characteristics and first-degree family histories of ischaemic heart disease (i.e. myocardial infarction or angina pectoris), stroke or hypertension were obtained from a structural self-administered questionnaire.

RESULTS

Subjects of both sexes with a family history of stroke showed significantly higher multivariable-adjusted means of ba-PWV than those without that trait (P values were 0.001 in men and 0.002 in women), while those with a family history of ischaemic heart disease did not. Subjects of both sexes with a family history of hypertension showed significantly higher age-adjusted means of ba-PWV than those without that trait, although these differences disappeared after further adjusting for blood pressure or multivariable covariates. When family histories of these diseases were inserted simultaneously into the same model, these results did not alter substantially.

CONCLUSION

A family history of stroke might be associated with increased arterial stiffness, independent of other known atherosclerotic risk factors, including hypertensive elements, in both sexes in the Japanese population.

Direct detection of resonant electron pitch angle scattering by whistler waves in a laboratory plasma

Resonant interactions between energetic electrons and whistler mode waves are an essential ingredient in the space environment, and in particular in controlling the dynamic variability of Earth's natural radiation belts, which is a topic of extreme interest at the moment. Although the theory describing resonant wave-particle interaction has been present for several decades, it has not been hitherto tested in a controlled laboratory setting. In the present Letter we report on the first laboratory experiment to directly detect resonant pitch angle scattering of energetic (∼keV) electrons due to whistler mode waves. We show that the whistler mode wave deflects energetic electrons at precisely the predicted resonant energy, and that varying both the maximum beam energy, and the wave frequency, alters the energetic electron beam very close to the resonant energy.

Cereal Intake Increases and Dairy Products Decrease Risk of Cognitive Decline among Elderly Female Japanese

BACKGROUND

If cognitive decline can be prevented through changes in daily diet with no medical intervention, it will be highly significant for dementia prevention.

OBJECTIVES

This longitudinal study examined the associations of different food intakes on cognitive decline among Japanese subjects.

DESIGN

Prospective cohort study.

SETTING

The National Institute for Longevity Sciences - Longitudinal Study of Aging, a community-based study.

PARTICIPANTS

Participants included 298 males and 272 females aged 60 to 81 years at baseline who participated in the follow-up study (third to seventh wave) at least one time.

MEASUREMENTS

Cognitive function was assessed with the Mini-Mental State Examination (MMSE) in all study waves. Nutritional intake was assessed using a 3-day dietary record in the second wave. Cumulative data among participants with an MMSE >27 in the second wave were analyzed using a generalized estimating equation. Multivariate adjusted odds ratios (OR) and 95% confidence intervals (CI) for an MMSE score ≤27 in each study wave according to a 1 standard deviation (SD) increase of each food intake at baseline were estimated, after adjusting for age, follow-up time, MMSE score at baseline, education, body mass index, annual household income, current smoking status, energy intake, and history of diseases.

RESULTS

In men, after adjusting for age, and follow-up period, MMSE score at baseline, the adjusted OR for a decline in MMSE score was 1.20 (95% CI, 1.02-1.42; p=0.032) with a 1-SD increase in cereal intake. After adjusting for education and other confounding variables, the OR for a decrease in MMSE score did not reach statistical significance for this variable. In women, multivariate adjusted OR for MMSE decline was 1.43 (95% CI, 1.15-1.77; p=0.001) with a 1-SD increase in cereal intake and 0.80 (95% CI, 0.65-0.98; p=0.034) with a 1-SD increase in milk and dairy product intake.

CONCLUSIONS

This study indicates that a 1-SD (108 g/day) decrease in cereal intake and a 1-SD (128 g/day) increase in milk and dairy product intake may have an influence of cognitive decline in community-dwelling Japanese women aged 60 years and older. Further studies are needed in order to explore the potential causal relationship.

Abundant daily non-sedentary activity is associated with reduced prevalence of metabolic syndrome and insulin resistance

BACKGROUND

Non-exercise activity thermogenesis has recently drawn attention because of its potential to prevent weight gain.

AIM

This study evaluated the relationships between the duration of daily non-sedentary activities and the prevalence of metabolic syndrome and insulin resistance (IR) in the Japanese population.

MATERIAL/SUBJECTS AND METHODS

A total of 518 eligible subjects (380 men and 138 women) who attended the Tokushima Prefectural General Health Checkup Center and participated in the baseline survey of a cohort study conducted in Tokushima Prefecture, Japan were analyzed. Information about lifestyle characteristics including leisure-time exercise and daily non-exercise activities was obtained from a questionnaire. Logistic and multiple linear regression analyses were performed to evaluate the associations between the duration of daily non-exercise non-sedentary activities (beyond sitting) and prevalence of metabolic syndrome (and its components) and IR.

RESULTS

Subjects with longer duration of daily non-sedentary activities had significantly lower adjusted odds ratios for metabolic syndrome (p for trend =0.024), abdominal obesity (p for trend =0.023), and low HDLcholesterol levels (p for trend =0.002), after adjustment for sex, age, and other probable covariates including leisure-time exercise. Longer duration of daily non-sedentary activities was further associated with lower homeostasis model of assessment- IR (HOMA-IR) values (p for trend =0.009).

CONCLUSIONS

Our results suggest that abundant daily non-sedentary activity might be associated with a lower prevalence of metabolic syndrome, especially for the components of central obesity and low HDL-cholesterol levels, and with a lower prevalence of IR, independent of leisure-time exercise.

Relationship of dietary factors and habits with sleep-wake regularity

The purpose of this study was to evaluate the associations between dietary factors and sleep-wake regularity in the Japanese population. We analyzed 1368 eligible subjects (931 men and 437 women) aged 35-69 years who had participated in the baseline survey of a cohort study in Tokushima Prefecture, Japan. Information on individual lifestyle characteristics, including dietary habits and sleep-wake regularity, was obtained by a self administrated questionnaire. Logistic regression analyses were performed to evaluate adjusted associations of the intake energy ratios of macronutrients, as well as intake frequency, and the amount of staple foods with sleep wake regularity. The lowest quartile of protein intake as well as the highest quartile of carbohydrates showed significantly higher multivariable-adjusted odds ratios of 2.1 (95% confidence interval, 1.3-3.3) and 2.1 (1.3-3.5), respectively, for poor sleep-wake regularity compared with the respective second quartile that is thought to be moderate intake. Regarding intake of staple foods, low weekly intake frequency at breakfast (<5 times/week), the lowest intake amount (<1 bowl or slice/roll) at breakfast, and the highest intake amount (>=2 bowls or slices/ rolls) at lunch and dinner exhibited significantly high adjusted odds ratios for poor sleep-wake regularity. Additionally adjusting for sleep duration, these results did not substantially alter. Our results suggested that low intake energy ratio of proteins and high intake energy ratio of carbohydrates, skipping intake of the staple foods at breakfast, and excessive intake amount of the staple foods at lunch and dinner may be associated with poor sleep-wake regularity.

Estrogen oversees the maintenance of the female genetic program in terminally differentiated gonochorists

The sexual plasticity of the gonads is not retained after the completion of sex differentiation in vertebrates, except in some hermaphroditic species. Here, we report that the depletion of estradiol-17β (E2) by aromatase inhibitors (AI) for up to six months resulted in a functional female-to-male sex reversal in sexually-mature adults of two gonochoristic fish species, Nile tilapia and medaka. The sex-reversed fish showed a typical male pattern of E2 and androgen levels, secondary sexual characteristics, and male-like sex behavior, producing fertile sperm. Conversely, co-treatment of E2 inhibited AI-induced sex reversal. In situ hybridization of medaka gonads during AI-induced sex reversal indicated that cysts on the dorsal side of the adult ovaries are the origin of germ cells and Sertoli cells in the newly formed testicular tissue. Gonochoristic fish maintain their sexual plasticity until adulthood and E2 plays a critical role in maintaining the female phenotype.