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

Miso, fermented soybean paste, suppresses high-fat/high-sucrose diet-induced muscle atrophy in mice

This study investigated the effects of miso, a traditional fermented soybean food in Japan, on muscle mass atrophy. Eight week old male C57BL/6J mice were fed high fat/high sucrose diet with or without miso for 12 weeks. A miso diet increased soleus muscle weights (p<0.05) and reduced intraperitoneal glucose tolerance and insulin tolerance (p<0.05). The miso diet downregulated the Tnfα and Ccl2 expression, related to inflammation, and Trim63 and Fbxo32 expression, related to muscle atrophy, in the soleus muscle (p<0.05). The miso diet increased short-chain fatty acids levels, including acetic, propanoic, and butanoic acids, in the feces, serum, and soleus muscle (p<0.05). According to the LEfSe analysis, the miso diet increased family Prevotellaceae, family Christensenellaceae, family Dehalobacterium, family Desulfitibacter; family Deferribacteraceae, order Deferribacterales, class Deferribacteres; and family Gemmatimonadaceae, order Gemmatimonadetes, and class Gemmatimonadales, whereas the miso diet decreased family Microbacteriaceae, order Micrococcales, class Actinobacteria, and family Lactobacillaceae. Miso suppressed high fat/high sucrose diet induced impaired glucose tolerance, low muscle strength, and muscle atrophy by improving dysbiosis and increasing short-chain fatty acids production and provides new insights into the preventive effects of fermented foods on sarcopenia.

Fermented soybean foods and diabetes

The number of patients with type 2 diabetes mellitus is increasing, and its prevention and management are important. One of the factors contributing to the increased incidence of type 2 diabetes mellitus is the change in dietary habits, including a Westernized diet. Fermented foods are foods that are transformed by the action of microorganisms to produce beneficial effects in humans and have been consumed for thousands of years. The production and consumption of fermented soy foods, including natto, miso, douchi, cheonggukjang, doenjang, tempeh, and fermented soy milk, are widespread in Asian countries. This review focuses on fermented soybean foods and summarizes their effects on diabetes. Fermentation increases the content of ingredients originally contained in soybeans and adds new ingredients that are not present in the original soybeans. Recent studies have revealed that fermented soybean food modifies the gut microbiota-related metabolites by modifying dysbiosis. Furthermore, it has been reported that fermented soybean foods have antioxidant, anti-inflammatory, and anti-diabetic effects. In recent years, fermented foods, including fermented soybeans, have shown various beneficial effects. Therefore, it is necessary to continue focusing on the benefits and mechanisms of action of fermented foods.

The Effects of a Western Diet vs. a High-Fiber Unprocessed Diet on Health Outcomes in Mice Offspring

Diet influences critical periods of growth, including gestation and early development. We hypothesized that a maternal/early life diet reflecting unprocessed dietary components would positively affect offspring metabolic and anthropometric parameters. Using 9 C57BL-6 dams, we simulated exposure to a Western diet, a high-fiber unprocessed diet (HFUD), or a control diet. The dams consumed their respective diets (Western [n = 3], HFUD [n = 3], and control [n = 3]) through 3 weeks of pregnancy and 3 weeks of weaning; their offspring consumed the diet of their mother for 4.5 weeks post weaning. Measurements included dual X-ray absorptiometry (DEXA) scans, feed consumption, body weight, blood glucose, and insulin and glycated hemoglobin (HbA1c) in the offspring. Statistical analyses included one-way ANOVA with Tukey's post hoc analysis. The offspring DEXA measures at 5 and 7.5 weeks post parturition revealed higher lean body mass development in the HFUD and control diet offspring compared to the Western diet offspring. An analysis indicated that blood glucose (p = 0.001) and HbA1c concentrations (p = 0.002) were lower among the HFUD offspring compared to the Western and control offspring. The results demonstrate that diet during gestation and early life consistent with traditional diet patterns may influence hyperglycemia and adiposity in offspring.

Probiotic-derived heptelidic acid exerts antitumor effects on extraintestinal melanoma through glyceraldehyde-3-phosphate dehydrogenase activity control

Background

Several microorganisms inhabit the mammalian gastrointestinal tract and are associated with the pathogenesis of various diseases, including cancer. Recent studies have indicated that several probiotics produce antitumor molecules and inhibit host tumor progression. We demonstrated that heptelidic acid (HA), a sesquiterpene lactone derived from the probiotic Aspergillus oryzae, exerts antitumor effects against pancreatic cancer in vitro and in vivo. In this study, the antitumor effects of HA against extraintestinal melanoma were assessed in vitro and in vivo.

Results

Sulforhodamine B (SRB) assay revealed that the growth of B16F10 cells was significantly inhibited by HA in a concentration-dependent manner. The enzymatic activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) decreased in proportion with the growth inhibition effect of HA. Moreover, oral HA administration significantly suppressed the growth of transplanted B16F10 tumors without any significant changes in biochemical test values. Moreover, GAPDH activity in the transplanted tumor tissues in the HA group significantly decreased compared with that in the PBS group.

Conclusion

This study suggests that orally administered HA was absorbed in the gastrointestinal tract, reached the cancer cells transplanted in the skin, and inhibited GAPDH activity, thereby inhibiting the growth of extraintestinal melanoma cells. Thus, this study proposes a novel system for extraintestinal tumor regulation via gut bacteria-derived bioactive mediators.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02530-0.

Associations of Dietary Salt and Its Sources with Hemoglobin A1c in Patients with Type 2 Diabetes Not Taking Anti-Diabetic Medications: Analysis Based on 6-Month Intervention with a Moderate Low-Carbohydrate Diet

OBJECTIVE

Based on biological studies, the hyperglycemic effect mediated by sodium-glucose co-transporter 1 in the intestine is stronger for foods containing more sodium chloride. Observational studies have demonstrated that type 2 diabetes (T2DM) incidence increases as salt intake increases. We aimed to elucidate associations of total salt and its sources with hemoglobin A1c (HbA1c) in patients with T2DM.

METHODS

We conducted an observational study using data from a 6-month moderate low-carbohydrate dietary intervention in 245 outpatients with T2DM (138 men) without antidiabetic medication. Intakes of total salt and its sources, carbohydrate and total energy were assessed at baseline and 6 months based on 3-day dietary records. Multiple regression analyses were performed to examine associations of Δtotal salt or its sources with ΔHbA1c.

RESULTS

Salt intake significantly decreased in men (change: -0.92 ± 3.53 g/day) but not in women (0.11 ± 2.28). HbA1c (men: -1.5 ± 1.6%; women: -0.9 ± 1.3%), carbohydrate (men: -115 ± 104 g/day; women: -64 ± 71) and total energy (men: -439 ± 660 kcal/day; women: -192 ± 438) significantly decreased in both sexes. Multiple regression analysis revealed that reducing intakes of total salt and salt from salty snacks, meat processed foods, Chinese noodles with soup and table salt by 1.0 g was associated with decreases in HbA1c of 0.11% 1.18% 0.47% 0.38% and 0.26%, respectively, in men, while reducing salt from miso by 1.0 g was associated with a decrease in HbA1c of 0.30% in women. The associations were dependent on Δcarbohydrate or Δtotal energy in men, while the association of Δsalt from miso in women was independent of them.

CONCLUSION

Reducing total salt and its sources had differential associations with HbA1c. Individual associations depended on Δcarbohydrate or Δtotal energy in men, while that of salt from miso in women was independent of them.

Habitual Miso (Fermented Soybean Paste) Consumption Is Associated with a Low Prevalence of Sarcopenia in Patients with Type 2 Diabetes: A Cross-Sectional Study

Insulin resistance is a risk of sarcopenia, and the presence of sarcopenia is high in patients with type 2 diabetes (T2DM). It has been reported that habitual miso soup consumption was associated with lower insulin resistance. However, the association between habitual miso consumption and the presence of sarcopenia in patients with T2DM, especially sex difference, was unclear. In this cross-sectional study, 192 men and 159 women with T2DM were included. Habitual miso consumption was defined as consuming miso soup regularly. Having both low skeletal muscle mass index (<28.64% for men, <24.12% for women) and low adjusted hand grip strength (<51.26% for men, <35.38% for women) was defined as sarcopenia. The proportions of sarcopenia were 8.7% in men and 22.6% in women. The proportions of habitual miso consumption were 88.0% in men and 83.6% in women. Among women, the presence of sarcopenia was lower in the group with habitual miso consumption (18.8% versus 42.3%, p = 0.018); however, there was no association between habitual miso consumption and the presence of sarcopenia in men. Habitual miso consumption was negatively associated with the presence of sarcopenia in women (adjusted odds ratio (OR), 0.20 (95% confidence interval (CI): 0.06-0.62), p = 0.005) but not in men. This study indicated that habitual miso consumption was associated with the presence of sarcopenia in women but not in men.

Effect of diet composition on insulin sensitivity in humans

Diet composition has a marked impact on the risk of developing type 2 diabetes and cardiovascular disease. Prospective studies show that dietary patterns with elevated amount of animal products and low quantity of vegetable food items raise the risk of these diseases. In healthy subjects, animal protein intake intensifies insulin resistance whereas plant-based foods enhance insulin sensitivity. Similar effects have been documented in patients with diabetes. Accordingly, pre-pregnancy intake of meat (processed and unprocessed) has been strongly associated with a higher risk of gestational diabetes whereas greater pre-pregnancy vegetable protein consumption is associated with a lower risk of gestational diabetes. Population groups that modify their traditional dietary habit increasing the amount of animal products while reducing plant-based foods experience a remarkable rise in the frequency of type 2 diabetes. The association of animal protein intake with insulin resistance is independent of body mass index. In obese individuals that consume high animal protein diets, insulin sensitivity does not improve following weight loss. Diets aimed to lose weight that encourage restriction of carbohydrates and elevated consumption of animal protein intensify insulin resistance increasing the risk of developing type 2 diabetes and cardiovascular disease. The effect of dietary components on insulin sensitivity may contribute to explain the striking impact of eating habits on the risk of type 2 diabetes and cardiovascular disease. Insulin resistance predisposes to type 2 diabetes in healthy subjects and deteriorates metabolic control in patients with diabetes. In nondiabetic and diabetic individuals, insulin resistance is a major cardiovascular risk factor.

Vegetarians have a lower fasting insulin level and higher insulin sensitivity than matched omnivores: A cross-sectional study

BACKGROUND AND AIMS

Potential associations of vegetarian diet patterns with fasting insulin (FI) and insulin sensitivity remain unclear. We aimed to investigate whether vegetarian diets were associated with FI and insulin sensitivity in a cross-sectional study in Chinese vegetarians and matched omnivores and then to test whether it is independent of body mass index (BMI).

METHODS AND RESULTS

This study included 279 vegetarians (73 vegans, 206 lacto-ovo-vegetarians) and 279 age- and sex-matched omnivores. Fasting blood glucose (FG) and FI concentrations were measured, and β-cell function (HOMA-β) and insulin resistance index (HOMA-IR) were used to evaluate insulin sensitivity. All blood glucose and insulin sensitivity indices were naturally log-transformed, and multiple-linear regression was used to determine the association between vegetarian diet patterns and insulin sensitivity after adjusting for confounders including BMI, visceral fat area, physical activity, sedentary time, income, alcohol consumption, and daily dietary intakes of macronutrients. Compared to omnivores, both vegan diet [β = -0.25, 95% CI: (-0.38, -0.14)] and lacto-ovo-vegetarian diet [β = -0.10, 95% CI: (-0.18, -0.01)] were negatively associated with HOMA-IR after adjusting for BMI. Vegan diet remained negatively associated with FI [β = -0.16, 95% CI: (-0.30, -0.01)] and HOMA-IR [β = -0.17, 95% CI: (-0.32, -0.03)] after adjusting for all confounders.

CONCLUSION

Vegetarian diet, especially vegan diet, is negatively associated with FI and IR, independent of BMI.

Dietary habits associated with reduced insulin resistance: The Nagahama study

AIMS

To investigate the association between insulin resistance assessed by a homeostasis model and dietary habits.

METHODS

Cross-sectional analysis using a community-based cohort, the Nagahama Prospective Cohort for Comprehensive Human Bioscience. Multiple linear regression analysis was performed with log HOMA-IR or log HOMA-β as the dependent variable and 20 dietary habits, tobacco smoking, medical history, family medical history of diabetes, age and BMI as the simultaneous independent variables in each sex separately.

RESULTS

Females (n = 2956) eating fish dishes every day had a HOMA-IR 0.90 times that of the reference group (P = 0.043). Females eating miso-soup every day had a HOMA-IR 0.95 times that of the reference group (P = 0.038). Males (n = 1371) eating vegetable dishes every day had a HOMA-IR 0.91 times that of the reference group (P = 0.003). Males eating egg dishes 4 to 5 times per week had a HOMA-IR 1.14 times that of the reference group (P = 0.011). Males eating fruits every day had a HOMA-IR 1.13 that of the reference group (P = 0.008).

CONCLUSIONS

Dietary habits associated with lower insulin resistance were eating fish dishes, miso soup or vegetable dishes every day and eating staple foods for dinner, egg dishes or fruits less frequently.

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.

Soyfood and isoflavone intake and risk of type 2 diabetes in Vietnamese adults

BACKGROUND/OBJECTIVES

Animal studies have demonstrated that soy isoflavones exert antidiabetic effects. However, evidence regarding the association between soyfood intake, a unique source of isoflavones, and type 2 diabetes remains inconclusive. This study assessed the relationship between habitual intakes of soyfoods and major isoflavones and risk of type 2 diabetes in Vietnamese adults.

SUBJECTS/METHODS

A hospital-based case-control study was conducted in Vietnam during 2013-2015. A total of 599 newly diagnosed diabetic cases (age 40-65 years) and 599 hospital-based controls, frequency matched by age and sex, were recruited in Hanoi, capital city of Vietnam. Information on frequency and quantity of soyfood and isoflavone intake, together with demographics, habitual diet and lifestyle characteristics, was obtained from direct interviews using a validated and reliable questionnaire. Unconditional logistic regression analyses were performed to examine the association between soy variables and type 2 diabetes risk.

RESULTS

Higher intake of total soyfoods was significantly associated with a lower risk of type 2 diabetes; the adjusted odds ratio (OR) for the highest versus the lowest intake was 0.31 (95% confidence interval (CI): 0.21-0.46; P<0.001). An inverse dose-response relationship of similar magnitude was also observed for total isoflavone intake (OR: 0.35; 95% CI: 0.24 to 0.49; P<0.001). In addition, inverse associations of specific soyfoods (soy milk, tofu and mung bean sprout) and major isoflavones (daidzein, genistein and glycitein) with the type 2 diabetes risk were evident.

CONCLUSIONS

Soyfood and isoflavone intake was associated with a lower type 2 diabetes risk in Vietnamese adults.

Animal-Protein Intake Is Associated with Insulin Resistance in Adventist Health Study 2 (AHS-2) Calibration Substudy Participants: A Cross-Sectional Analysis

Background: High intakes of total and animal protein are associated with the risk of type 2 diabetes (T2D). The influence of protein type on insulin resistance, a key precursor of T2D, has not been extensively studied. Objective: The aim of this study was to determine the associations between dietary total, animal, and plant protein intakes as well as the animal-to-plant protein (AP) intake ratio with insulin resistance in middle-aged and older adults. Methods: This was a cross-sectional analysis in 548 participants (mean ± SD age: 66.2 ± 13.7 y) from the calibration substudy of the AHS-2 (Adventist Health Study 2) cohort. Participants consumed diets with a low AP intake ratio. Dietary intakes of total and particular types of protein were calculated from six 24-h dietary recalls. Participants completed a self-administered questionnaire on demographic, lifestyle, health, diet intake, and physical activity characteristics. Anthropometric variables including weight, height, and waist circumference were measured. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated by using fasting serum glucose and insulin. Multiple linear regression models were used to test the relations between total and specific protein intakes with insulin resistance. Results: The ranges of dietary intakes of animal and plant protein and the AP intake ratio were 0.4-87.4 and 14.0-79.2 g/d and 0.02-4.43, respectively. Dietary intakes per 10-g/d increments of total protein (β: 0.11; 95% CI: 0.02, 0.21) and animal protein (β: 0.11; 95% CI: 0.01, 0.20) and the AP intake ratio (β: 1.82; 95% CI: 0.80, 2.84) were positively related to HOMA-IR. Plant protein was not significantly related to insulin resistance. Conclusion: Total and animal protein intakes and the AP intake ratio were positively associated with HOMA-IR in adults with relatively a low intake of animal protein and a high consumption of plant protein.