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Red meat and processed meat intake has been linked to increased risk of type 2 diabetes; however, evidence from Asia is limited and inconsistent. We prospectively examined the association of intake of total meat and its subtype with type 2 diabetes in a Japanese working population. Participants were 2709 workers aged 18-78 years who reported no history of diabetes when they responded to a health survey for the first time between 2012 and 2019. Dietary intake was assessed using a validated self-administered diet history questionnaire. The incidence of type 2 diabetes was assessed via annual health checkups from baseline through March 2023. Type 2 diabetes was defined as fasting blood glucose ≥ 126 mg/dl, casual blood glucose ≥ 200 mg/dl, HbA1c ≥ 6·5 %, self-report of diabetes or current use of anti-diabetic drugs. Hazard ratios according to tertile of meat intake were estimated using Cox proportional hazards regression. During 16 119 person-years of follow-up, 135 (5·0 %) workers developed type 2 diabetes. Intakes of total meat, red meat, processed meat and poultry were not associated with risk of type 2 diabetes. After adjustment for covariates, hazard ratios for the highest v . lowest tertile of meat intake were 1·01 (95 % CI 0·63, 1·62) for total meat, 1·02 (95 % CI 0·66, 1·58) for red meat, 0·99 (95 % CI 0·65, 1·49) for processed meat and 1·13 (95 % CI 0·71, 1·80) for poultry. Our findings suggest that meat intake is not associated with the risk of type 2 diabetes among Japanese workers.

We examined the association of dietary non-enzymatic antioxidant capacity (NEAC) in overall diet, and separately from foods and beverages, with serum liver enzymes in a Japanese working population. This cross-sectional study was conducted among 1791 employees aged 18-69 years, who underwent a comprehensive health checkup in 2012-2013. A brief validated self-administered diet-history questionnaire was used for dietary assessment, and dietary NEAC intake was determined from databases of NEAC values, obtained using ferric reducing-antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. The dietary NEAC intake was calculated by multiplying the estimated NEAC values by the amounts consumed and summing the resulting values. A multiple-regression analysis was performed to explore the association between dietary NEAC intake and the serum levels of liver enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT)), after adjustment for confounding factors. No significant associations were found between overall dietary NEAC intake and AST (FRAP, p for trend = 0.97; ORAC, p = 0.72), ALT (FRAP, p = 0.73; ORAC, p = 0.92), and GGT (FRAP, p = 0.96; ORAC, p = 0.19) levels. Food-derived, but not beverage-derived, NEAC intake was inversely associated with serum GGT levels (FRAP, p for trend = 0.001; ORAC, p = 0.02), particularly among older participants and those with high serum ferritin concentrations. The results imply that overall dietary NEAC intake is not associated with liver dysfunction, and that the NEAC values from foods may be inversely associated with serum GGT levels.

Background & Aim: It is not clear whether diet quality influences mental health. We prospectively investigated the association of adherence to the Japanese dietary guidelines with depressive symptoms in a Japanese working population., Methods: Participants were 909 workers (aged 19-68 years) without depressive symptoms at baseline who completed both baseline and 3-year follow-up surveys. Dietary intake was assessed with a validated self-administered diet history questionnaire. Adherence to the Japanese Food Guide Spinning Top was measured based on consumption of the recommended number of servings of grains, vegetables, fish and meat, milk, and fruits, as well as total energy intake and energy from snacks and alcoholic beverages. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Multiple logistic regression was used to estimate the odds ratio of depressive symptoms according to tertile of adherence score, with adjustment for covariates., Results: At the time of the 3-year follow-up survey, 153 (16.8%) workers were newly identified as having depressive symptoms (CES-D score of ≥16). The adherence score was not associated with depressive symptoms after 3 years. The multivariable-adjusted odds ratios (95% confidence interval) for the lowest through highest tertiles of dietary score were 1.00 (reference), 0.91 (0.57-1.45), and 1.23 (0.76-1.99) (P for trend = 0.41). The odds ratios for severe depressive symptoms (CES-D score of ≥23) tended to decrease with increasing adherence score., Conclusions: Our results suggest that diet based on the Japanese Food Guide Spinning Top was not prospectively associated with risk of depressive symptoms among Japanese., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background & Aims: Oxidative stress has been suggested to play an important role in the pathophysiology of depression, and a diet high in antioxidants may improve mood. However, studies addressing this issue are scarce. The aim of this cohort study was to investigate the prospective association between dietary non-enzymatic antioxidant capacity (NEAC) in overall diet and depressive symptoms in Japanese employees. Additionally, we examined the association separated by dietary NEAC sources., Method: Participants were 911 workers without depressive symptoms at baseline and participated in 3-y follow-up survey. Dietary NEAC was determined from a database of NEAC measurements obtained by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). Dietary NEAC was calculated by multiplying the estimated NEAC values with the consumed amount and summing up those values. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to estimate odds ratios of depressive symptoms according to overall NEAC and separately from foods and beverages., Results: At 3-y follow-up, 153 (16.8%) workers were newly identified as having depressive symptom. No significant associations were found between higher level of overall dietary NEAC and decreased risk of depressive symptoms after adjustment for potential confounders (overall: FRAP, P for trend = 0.19 and ORAC, P for trend = 0.20). Likewise, neither higher dietary NEAC from foods nor beverages were related with lower depressive symptoms., Conclusion: Our findings did not support an inverse association between dietary NEAC and the risk of depressive symptoms in Japanese workers., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest. T.K. and M.E. are health professionals at the Furukawa Electric Corporation. I. Kabe is a health professional at Kubota Corporation., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Hypertension has become a major public health issue worldwide. Whole grains contain higher levels and a broader range of nutrients with potential health benefits and may decrease the risk of hypertension. However, no prospective studies have investigated this association in the high-income Asia Pacific region, which has the lowest whole grain intake worldwide. Thus, we examined the prospective association between whole grain consumption and the development of hypertension in Japan. Participants included 944 working Japanese adults aged 19-68 years who had no hypertension at baseline and completed a 3-year follow-up survey. Whole grain consumption was assessed via a self-administered dietary questionnaire. Multivariate logistic regression analysis was carried out to examine the association between whole grain consumption and hypertension, adjusting for potential confounding factors, such as sociodemographic, lifestyle, dietary, and occupational characteristics. After 3 years, 9.4% (86 cases) of the study participants had developed hypertension. More frequent whole grain consumption, classified as an intake frequency of "sometimes or always", was associated with lower odds of hypertension (multivariate-adjusted odds ratio: 0.36; 95% confidence interval: 0.16-0.83; p for trend = 0.04) compared with no consumption. Consuming more whole grains may decrease the risk of developing hypertension., Competing Interests: The authors declare no conflicts of interest. M.E., T.K., and I.K. (Isamu Kabe) are healthcare professionals and employees of the Furukawa Electric Corporation.

Breakfast consumption has been suggested to influence mood, but prospective evidence on this issue is limited. We prospectively investigated the association between the frequency of breakfast consumption and the risk of depressive symptoms in Japanese employees. Participants were 716 employees aged 19-68 years who were free from depressive symptoms and mental disorders at baseline and who attended the 3-year follow-up survey. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. The frequency of breakfast consumption was categorized into "daily", "5-6 times/week", "3-4 times/week", "1-2 times/week", or "≤1 times/week". Logistic regression was used to estimate odds ratios of depressive symptoms according to breakfast consumption adjusted for dietary and lifestyle factors. Participants who consumed breakfast ≤1 times/week had an increased risk of depressive symptoms compared to those who ate breakfast every day, even after adjusting for other dietary factors (multivariable-adjusted odds ratio 2.92; 95% confidence interval, 1.37-6.22) The risk of depressive symptoms tended to increase with decreasing frequency of breakfast consumption (P for trend = 0.02). The omission of breakfast is related to increased risk of depressive symptoms among Japanese employees, independently of other dietary and non-dietary factors., (Copyright © 2019. Published by Elsevier B.V.)

Objective: We explored the association of 3-year adherence to a dietary pattern based on nutrients that may be related to mood with the development of depressive symptoms in Japanese employees., Methods: Participants were 903 employees free from depressive symptoms at baseline and who attended the 3-year follow-up. Participants with depressive symptoms were defined as those with a score ≥16 on the Center for Epidemiologic Studies Depression Scale. Dietary patterns were derived using reduced-rank regression at baseline and at the 3-year follow-up survey using a validated, self-administered diet history questionnaire. Based on changes in dietary pattern scores between baseline and follow-up surveys, participants were categorized into four groups: Maintained high scores, improved scores, decreased scores, and maintained low scores. Logistic regression was used to estimate odds ratios of depressive symptoms according to changes in dietary pattern scores., Results: Maintaining high or improving adherence to a diet rich in vegetables, mushrooms, seaweeds, soybean products, green tea, potatoes, fruits, and fish and low in rice over 3 y was associated with a decreased risk of depressive symptoms. The multivariable-adjusted odds ratio (95% confidence intervals) of developing depressive symptoms for maintained high scores versus maintained low scores was 0.57 (0.35-0.93) and for improved scores versus maintained low scores was 0.54 (0.29-1.01). The association with the severe depressive status was more pronounced., Conclusion: Maintaining high or improving adherence to a dietary pattern derived by reduced-rank regression is associated with a lower risk of depression among Japanese employees., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background & Aims: Magnesium may play an important role in cardio-metabolic abnormalities, including type 2 diabetes, but epidemiological evidence linking magnesium status to glucose metabolism is limited among Asians. We cross-sectionally examined the association of dietary and serum magnesium with markers of glucose metabolism among Japanese subjects., Methods: Subjects were 1796 workers, aged 18-78 years, who participated in a health survey. Dietary magnesium intake was assessed with a validated brief diet history questionnaire. Serum magnesium concentrations were measured using an enzymatic method. Multivariable linear regression models were used to estimate means of fasting insulin, fasting plasma glucose, homeostatic model assessment of insulin resistance (HOMA-IR), homeostatic model assessment of β-cell function (HOMA-β), and glycated hemoglobin (HbA1c), with adjustments made for potential confounding variables., Results: Dietary magnesium was inversely associated with HOMA-IR (P trend  = 0.01). Multivariable-adjusted means (95% confidence intervals) of HOMA-IR for the lowest to highest quartiles of dietary magnesium were 0.94 (0.89-0.99), 0.92 (0.88-0.97), 0.88 (0.83-0.92), and 0.86 (0.81-0.90). Serum magnesium concentrations were also inversely associated with HOMA-IR (P trend  = 0.04) and HbA1c (P trend <0.01). Multivariable-adjusted means (95% confidence intervals) for the lowest to highest quartiles of serum magnesium were 0.94 (0.90-0.98), 0.87 (0.83-0.91), 0.90 (0.85-0.95), and 0.86 (0.81-0.92) for HOMA-IR and 5.41 (5.36-5.45), 5.33 (5.28-5.37), 5.30 (5.25-5.36), and 5.28 (5.22-5.35) for HbA1c. Excluding subjects with diabetes did not materially change the association between dietary magnesium and HOMA-IR (P trend <0.01), while it attenuated the association of serum magnesium with HOMA-IR (P trend  = 0.27) and HbA1c (P trend  = 0.15)., Conclusions: The present findings suggest that lower dietary magnesium, but not serum magnesium, is associated with IR in apparently healthy adults., (Copyright © 2018 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.)

Objective: Dietary fiber may play a favorable role in mood through gut microbiota, but epidemiologic evidence linking mood to dietary fiber intake is scarce in free-living populations. We investigated cross-sectionally the associations of dietary intakes of total, soluble, insoluble, and sources of fiber with depressive symptoms among Japanese workers., Methods: Participants were 1977 employees ages 19-69 y. Dietary intake was assessed via a validated, brief self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to estimate odds ratios of depressive symptoms adjusted for a range of dietary and non-dietary potential confounders., Results: Dietary fiber intake from vegetables and fruits was significantly inversely associated with depressive symptoms. The multivariable-adjusted odds ratios (95% confidence intervals) for the lowest through the highest tertile of vegetable and fruit fiber were 1.00 (reference), 0.80 (0.60-1.05), and 0.65 (0.45-0.95), respectively (P for trend = 0.03). Dietary intake of total, soluble, insoluble, and cereal fiber was not associated with depressive symptoms., Conclusions: Higher dietary fiber intake from vegetables and fruits may be associated with lower likelihood of having depressive symptoms., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background & Aims: Acid-base imbalance has been suggested to play an important role in certain cardio-metabolic abnormalities, including type 2 diabetes; however, epidemiological evidence linking dietary acid load to glucose metabolism is lacking. We examined the association of dietary acid load with markers of insulin resistance (IR), insulin secretion, and blood glucose status among Japanese workers., Methods: The study subjects were 1732 workers, aged 19-69 years, who completed a health survey at a periodic checkup. Dietary intake was assessed using a validated brief diet history questionnaire. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores were derived from nutrient intake. A multilevel linear regression model was used to estimate the means of fasting insulin, fasting plasma glucose, homeostatic model assessment of IR (HOMA-IR) score, homeostatic model assessment of β-cell function (HOMA-β) score and glycated hemoglobin (HbA1c) level with adjustment for potential confounding variables., Results: PRAL was positively associated with HOMA-IR score (Ptrend = 0.045); the multivariable-adjusted means (95% confidence intervals) for the HOMA-IR scores for the lowest through the highest quartiles of PRAL were 0.88 (0.82-0.94), 0.92 (0.86-0.98), 0.92 (0.86-0.98), and 0.94 (0.88-1.01). A similar association was observed between NEAP and HOMA-IR scores (Ptrend = 0.03). In the stratified analyses, these positive associations were confined to subjects with lower BMIs (<23 kg/m(2)) (Ptrend = 0.03 and 0.01 for PRAL and NEAP, respectively). NEAP score was positively associated with HOMA-β score (Ptrend = 0.03). Dietary acid load score was not appreciably associated with fasting glucose or HbA1c levels., Conclusions: The present findings suggest that high dietary acid load is associated with IR among apparently healthy adults., (Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

Objective: Experimental studies have shown that some nutrients are involved in initiating and maintaining sleep, but epidemiological evidence on overall dietary patterns and insomnia is scarce. We investigated the relationship between dietary patterns and sleep symptoms in a Japanese working population., Methods: The participants were 2025 workers, aged 18-70 years, who participated in a health survey during a periodic checkup in 2012 and 2013. Dietary intake was assessed with a self-administered diet history questionnaire. Dietary patterns were extracted by principal component analysis on the basis of the energy-adjusted intake of 52 food and beverage items. Sleep duration, difficulty initiating and maintaining sleep, and poor quality of sleep were self-reported. Logistic regression was used to estimate the odds ratios of each sleep symptom according to quartile categories of each dietary pattern with adjustment for potential confounding variables., Results: We identified three major dietary patterns. A healthy pattern, characterized by a high intake of vegetables, mushrooms, potatoes, seaweeds, soy products, and eggs, was associated with a decreased prevalence of difficulty initiating sleep once or more a week (P for trend = 0.03); the multivariate adjusted odds ratio in the highest quartile of this score compared with the lowest was 0.75 (95% CI: 0.57-0.99). This association persisted after the exclusion of individuals with severe depressive symptoms. However, there was no significant association with difficulty initiating sleep at least three times a week., Conclusions: Our findings suggest that a healthy dietary pattern may be associated with difficulty initiating sleep at least once a week., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Objective: Acid-base status has been suggested to influence blood pressure, but there is a paucity of epidemiologic evidence linking dietary acid load to hypertension. We examined cross-sectionally the association between dietary acid load and hypertension in a Japanese working population., Methods: Data were derived from health surveys from 2028 employees, ages 18 to 70 y, in two workplaces in Japan. A validated brief diet history questionnaire was used to assess diet. Two measures were used to characterize dietary acid load: potential renal acid load and estimated net endogenous acid production, which were derived from nutrient intakes. Multilevel logistic regression was used to examine the association between dietary acid load and hypertension with adjustment of potential confounding variables., Results: High dietary acid load was suggestively associated with increased prevalence of hypertension. The multivariable adjusted odds ratios (95% confidence interval) of hypertension for the lowest through highest tertiles of net endogenous acid production were 1.00 (reference), 1.07 (0.80-1.42), and 1.33 (0.998-1.78), respectively (P for trend = 0.053). This positive association was statistically significant among normal-weight (body mass index <23 kg/m(2); P for trend = 0.03) and non-shift workers (P for trend = 0.04). Similar positive associations were observed between potential renal acid load and hypertension., Conclusions: The present findings suggest that high dietary acid load may be associated with increased prevalence of hypertension among those who were normal weight and non-shift workers., (Copyright © 2015 Elsevier Inc. All rights reserved.)