Dietary fiber intake and risk of type 2 diabetes: a dose-response analysis of prospective studies. Eur J Epidemiol. 2014;29:79-88. [PMID: 24389767 DOI: 10.1007/s10654-013-9876-x]

Effect of Continuous and Discontinuous Microwave-Assisted Heating on Starch-Derived Dietary Fiber Production

Dietary fiber can be obtained by dextrinization, which occurs while heating starch in the presence of acids. During dextrinization, depolymerization, transglycosylation, and repolymerization occur, leading to structural changes responsible for increasing resistance to starch enzymatic digestion. The conventional dextrinization time can be decreased by using microwave-assisted heating. The main objective of this study was to obtain dietary fiber from acidified potato starch using continuous and discontinuous microwave-assisted heating and to investigate the structure and physicochemical properties of the resulting dextrins. Dextrins were characterized by water solubility, dextrose equivalent, and color parameters (L* a* b*). Total dietary fiber content was measured according to the AOAC 2009.01 method. Structural and morphological changes were determined by means of SEM, XRD, DSC, and GC-MS analyses. Microwave-assisted dextrinization of potato starch led to light yellow to brownish products with increased solubility in water and diminished crystallinity and gelatinization enthalpy. Dextrinization products contained glycosidic linkages and branched residues not present in native starch, indicative of its conversion into dietary fiber. Thus, microwave-assisted heating can induce structural changes in potato starch, originating products with a high level of dietary fiber content.

An Update on the Epidemiology of Type 2 Diabetes: A Global Perspective

Type 2 diabetes (T2D) is a public health burden associated with immense health care and societal costs, early death, and morbidity. Largely because of epidemiologic changes, including nutrition transitions, urbanization, and sedentary lifestyles, T2D is increasing in every region of the world, particularly in low-income and middle-income countries. This article highlights global trends in T2D and discusses the role of genes, early-life exposures, and lifestyle risk factors in the cause of T2D, with an emphasis on populations in current hotspots of the epidemic. It also considers potential impacts of the coronavirus disease 2019 pandemic and T2D prevention policies and action.

De novo biosynthesis of garbanzol and fustin in Streptomyces albus based on a potential flavanone 3-hydroxylase with 2-hydroxylase side activity

Flavonoids are important plant secondary metabolites, which were shown to have antioxidant, anti-inflammatory or antiviral activities. Heterologous production of flavonoids in engineered microbial cell factories is an interesting alternative to their purification from plant material representing the natural source. The use of engineered bacteria allows to produce specific compounds, independent of soil, climatic or other plant-associated production parameters. The initial objective of this study was to achieve an engineered production of two interesting flavanonols, garbanzol and fustin, using Streptomyces albus as the production host. Unexpectedly, the engineered strain produced several flavones and flavonols in the absence of the additional expression of a flavone synthase (FNS) or flavonol synthase (FLS) gene. It turned out that the heterologous flavanone 3-hydroxylase (F3H) has a 2-hydroxylase side activity, which explains the observed production of 7,4'-dihydroxyflavone, resokaempferol, kaempferol and apigenin, as well as the biosynthesis of the extremely rare 2-hydroxylated intermediates 2-hydroxyliquiritigenin, 2-hydroxynaringenin and probably licodione. Other related metabolites, such as quercetin, dihydroquercetin and eriodictyol, have also been detected in culture extracts of this recombinant strain. Hence, the enzymatic versatility of S. albus can be conveniently exploited for the heterologous production of a large diversity of plant metabolites of the flavonoid family.

Effects of Daily Kelp (Laminaria japonica) Intake on Body Composition, Serum Lipid Levels, and Thyroid Hormone Levels in Healthy Japanese Adults: A Randomized, Double-Blind Study

To investigate whether supplementation with iodine-reduced kelp (Laminaria japonica) powder decreases body fat composition in overweight Japanese subjects, a randomized, double-blind, placebo-controlled intervention study was conducted in 50 Japanese subjects with body mass index (BMI) ≥25 and <30 kg/m2. Subjects were randomly assigned to consume thirty tablets/d (10 tablets orally, 3 times/d) containing either iodine-reduced kelp powder (test, 6 g kelp powder corresponding to 3 g alginate/d) or kelp-free powder (placebo) for 8 weeks. Anthropometric measurements, blood lipids, and serum thyroid hormone levels were obtained before and after the trial. Body fat percentage was significantly decreased in male subjects from the test group compared with the placebo group. The same tendency was observed for body weight (p = 0.065) and BMI (p = 0.072) in male subjects. No significant changes in anthropometric measurements or visceral fat area were observed in female subjects. Serum thyroid hormone concentrations did not increase after 1.03 mg/d of iodine supplementation through kelp intake. The intake of iodine-reduced kelp powder led to significant and safe reductions in body fat percentage in overweight male subjects. The consumption of kelp high in alginate may contribute to preventing obesity without influencing thyroid function in Japanese subjects with a relatively high intake of iodine from seaweed.

Dietary Fibre Modulates the Gut Microbiota

Dietary fibre has long been established as a nutritionally important, health-promoting food ingredient. Modern dietary practices have seen a significant reduction in fibre consumption compared with ancestral habits. This is related to the emergence of low-fibre “Western diets” associated with industrialised nations, and is linked to an increased prevalence of gut diseases such as inflammatory bowel disease, obesity, type II diabetes mellitus and metabolic syndrome. The characteristic metabolic parameters of these individuals include insulin resistance, high fasting and postprandial glucose, as well as high plasma cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Gut microbial signatures are also altered significantly in these cohorts, suggesting a causative link between diet, microbes and disease. Dietary fibre consumption has been hypothesised to reverse these changes through microbial fermentation and the subsequent production of short-chain fatty acids (SCFA), which improves glucose and lipid parameters in individuals who harbour diseases associated with dysfunctional metabolism. This review article examines how different types of dietary fibre can differentially alter glucose and lipid metabolism through changes in gut microbiota composition and function.

Anti-diabetic effects of the soluble dietary fiber from tartary buckwheat bran in diabetic mice and their potential mechanisms

Background

Tartary buckwheat has beneficial effects on glucose and lipid metabolism of patients with type 2 diabetes mellitus. However, the physiological effects of a soluble dietary fiber (SDF) from tartary buckwheat have rarely been studied, especially in vivo.

Objective

This study aimed to examine the hypoglycemic and hypolipidemic effects of SDF from tartary buckwheat bran on high-fat diet/streptozotocin-induced diabetic mice.

Design

The SDF of tartary buckwheat bran was collected according to the Association of Official Analytical Chemists method 991.43. Diabetic mice were treated with high-fat diets supplemented with 0.5, 1, and 2% SDF for 8 weeks. Parameters related to glucose and lipid metabolism and relevant mechanisms, including the excretion of short-chain fatty acids and the glycemic signaling pathway in the liver, were investigated. In addition, the structural characterization of a purified polysaccharide from SDF of tartary buckwheat bran was illustrated.

Result

Supplementation with SDF in the diet resulted in reduced levels of fasting blood glucose, improved oral glucose tolerance, increased levels of liver glycogen and insulin, as well as improved lipid profiles in both the serum and liver, in diabetic mice. The amelioration of glucose and lipid metabolism by SDF was accompanied by an increase in the short-chain fatty acid levels in the cecum and co-regulated by hepatic adenosine-5′-monophosphate-activated protein kinase (AMPK) phosphorylation. A neutral tartary buckwheat polysaccharide with an average molecular weight of 19.6 kDa was purified from the SDF, which consisted mainly of glucose with α-glycosidic bonds.

Conclusions

The SDF of tartary buckwheat bran exhibits hypoglycemic and hypolipidemic effects in diabetic mice, contributing to the anti-diabetic mechanisms of tartary buckwheat.

Fibre Intake Is Associated with Cardiovascular Health in European Children

BACKGROUND

We aimed at analysing the association between dietary fibre intake during childhood and cardiovascular health markers.

METHODS

We used observational longitudinal analysis and recorded diet using 3-day diaries at the ages of 3, 4, 5, 6, and 8 years in children from the EU Childhood Obesity Project Trial. At the age of 8, waist circumference, systolic and diastolic blood pressure (SBP and DBP) and biochemical analyses (lipoproteins, triglycerides and homeostasis model for insulin resistance (HOMA-IR)) were evaluated. Those parameters were combined into a cardiometabolic risk score through the sum of their internal z-scores.

RESULTS

Four-hundred children (51.8% girls) attended to the 8-year visit with a 3-day diary. Adjusted linear regression models showed that children who repeatedly stayed in the lowest tertile of fibre intake during childhood had higher HOMA-IR (p = 0.004), higher cardiometabolic risk score (p = 0.02) and a nonsignificant trend toward a higher SBP at 8 years. The higher the dietary intake of soluble fibre (from fruits and vegetables) at 8 years, the lower the HOMA-IR and the cardiometabolic risk score (p = 0.002; p = 0.004). SBP was directly associated with fibre from potatoes and inversely with fibre from nuts and pulses.

CONCLUSION

A diet rich in dietary fibre from fruits, vegetables, pulses and nuts from early childhood was associated to a healthier cardiovascular profile, regardless of children's weight.

Association Between Dietary Fiber Intake and Non-alcoholic Fatty Liver Disease in Adults

Background: Evidence on the association of non-alcoholic fatty liver disease (NAFLD), a public health concern, with dietary fiber intake is inconsistent.

Objective: To investigate the relationship between dietary fiber intake from different sources and NAFLD risk in US adults.

Methods: Data were collected from the 2007–2014 National Health and Nutrition Examination Survey. NAFLD was defined as a United States Fatty Liver Index ≥30, and dietary fiber intake was assessed through two 24-h dietary recall interviews. Logistic regression and restricted cubic spline models were used to explore the relationship of dietary intakes of total, cereal, fruit, and vegetable fiber with NAFLD risk.

Results: A total of 6,613 participants, aged more than 20 years, were included in this study. After adjusting for multiple confounding factors, the odds ratios and 95% confidence intervals of NAFLD for the highest quartile vs. lowest quartile intakes of total, cereal, fruit, and vegetable fiber were 0.12 (0.08–0.16), 0.25 (0.19–0.33), 0.41 (0.33–0.52), and 0.42 (0.32–0.56), respectively. In stratified analyses by sex and age, statistically significant negative associations of dietary intakes of total, cereal, fruit, and vegetable fiber with NAFLD risk were observed in all participants. Dose-response analysis indicated a non-linear correlation between NAFLD risk and dietary intake of total fiber, whereas the relationship was linear for cereal, fruit, and vegetable fiber intakes.

Conclusion: Total, cereal, fruit, and vegetable fiber intakes exhibit negative correlations with NAFLD risk in the general adult population in the United States.

Effects of soluble fiber supplementation on glycemic control in adults with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & AIMS

Soluble dietary fiber is prompted as an important part of reducing blood glucose, ameliorating insulin resistance and controlling body weight. Thus, we performed this systematic review and meta-analysis of randomized controlled trials (RCTs) to quantify and synthesize the effects of soluble fiber supplementation on glycemic control and BMI modification in adults with type 2 diabetes.

METHODS

We searched MEDLINE, Embase, Web of Science, ClinicalTrials.gov, and Cochrane databases until February 13, 2020 to identify RCTs that detected the effects of soluble fiber supplementation on glycemic control in adults with type 2 diabetes. A random-effects model with the generic inverse variance method was used to analyze the pooled data. The meta-regression and subgroup analyses were conducted to identify the variables that influenced the pooled results. The robust error meta-regression model was used to conduct the dose-response test. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was undertaken to evaluate the overall quality of the evidence.

RESULTS

A total of 29 RCTs (33 comparisons) involving 1517 participants were identified in this meta-analysis. Results showed that supplemental soluble dietary fiber significantly reduced glycosylated hemoglobin (HbA1c, MD -0.63%, 95% CI [-0.90, -0.37]; P < 0.00001), fasting plasma glucose (FPG, MD -0.89 mmol/L, 95% CI [-1.28, -0.51]; P < 0.00001), fasting insulin (SMD -0.48, 95% CI [-0.80, -0.17]; P = 0.003), homeostatic model assessment of insulin resistance (HOMA-IR, SMD -0.58, 95% CI [-0.86, -0.29], P < 0.0001), fructosamine (SMD -1.03, 95% CI [-1.51, -0.55]; P < 0.0001), 2-h postprandial plasma glucose (SMD -0.74, 95% CI [-1.00, -0.48]; P < 0.00001), and BMI (SMD -0.31, 95% CI [-0.61, -0.00], P = 0.05) compared with control diets in patients with type 2 diabetes. Specifically, dose-response meta-analyses presented that a daily dosage of 7.6-8.3 g was recommended.

CONCLUSION

Intake of soluble fiber supplementation is effective in improving glycemic control and BMI level in type 2 diabetes and is also a convenient way to help individuals meet standard dietary fiber needs. But due to the evidence of substantial heterogeneity in most pooled estimates, further long-term and high-quality RCTs are needed.

Effect of Eating Glutinous Brown Rice Twice a Day for 6 Weeks on Serum 1,5-Anhydroglucitol in Japanese Subjects without Diabetes

We have previously demonstrated that eating glutinous brown rice (GBR) for 1 day or 8 weeks was well accepted and improved glycemic control in patients with type 2 diabetes. The present study evaluated whether eating GBR could also improve glucose metabolism in subjects without diabetes. A prospective 6-week, single-center, randomized, open-label, parallel-group study was carried out in subjects receiving annual medical checkup at our hospital. A total of 42 subjects were randomly assigned to continue their regular diet (RD group) or to switch GBR twice a day (GBR group). The primary outcome was the change in the serum concentration of 1,5-anhydroglucitol (1,5-AG) from baseline after the 6-week dietary intervention. One subject was excluded from the analysis because of a traffic accident. After 6 weeks, the serum 1,5-AG was significantly increased in the GBR group and the mean treatment difference (GBR group - RD group) was 1.1 µg/mL (95% CI: 0.6 to 1.6, p=0.022). Body mass index decreased significantly in both groups, with no significant difference between them (p=0.210). There were no changes in fasting plasma glucose, fasting insulin, or eating behavior. Intake of GBR for 6 weeks significantly increased serum 1,5-AG in Japanese subjects without diabetes. The increase of 1,5-AG may have been due to the alleviation of postprandial hyperglycemia, which could be effective for the primary prevention of diabetes.

Preventive Role of Diet Interventions and Dietary Factors in Type 2 Diabetes Mellitus: An Umbrella Review

BACKGROUND

Although the body of evidence indicates clear benefits of dietary modifications for prevention of type-2 diabetes mellitus (T2DM), it may be difficult for healthcare providers to recommend which diet interventions or dietary factors are appropriate for patients as there are too many modalities available. Accordingly, we performed an umbrella review to synthesize evidence on diet interventions and dietary factors in prevention of T2DM.

METHODS

Medline and Scopus databases were searched for relevant studies. Systematic reviews with meta-analyses of randomized-controlled trial or observational studies were eligible if they measured effects of diet interventions and/or dietary factors including dietary patterns, food groups, and nutrients on risk of T2DM. The effect of each diet intervention/factor was summarized qualitatively.

RESULTS

Sixty systematic reviews and meta-analyses were eligible. Results of the review suggest that healthy dietary patterns such as Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diets, and high consumption of whole grains, low-fat dairy products, yogurt, olive oil, chocolate, fiber, magnesium, and flavonoid significantly reduced the risk of T2DM. In contrast, high glycemic index and glycemic load diets, high consumption of red and processed meat, and sugar or artificial sugar-sweetened beverages significantly increased risk of T2DM. Prescribing diet interventions with or without physical activity interventions significantly decreased risk of T2DM in both high-risk and general population.

CONCLUSION

High consumption of Mediterranean and DASH diet, and interventions that modified the quality of diet intake significantly reduced risk of T2DM especially in the high-risk population. These lifestyle modifications should be promoted in both individual and population levels to prevent and decrease burden from T2DM in the future.

Dietary fiber intake and risk of type 2 diabetes in a general Japanese population: The Hisayama Study

Aims/Introduction

The investigation of the influence of dietary fiber intake on the incidence of type 2 diabetes in a general Japanese population.

Materials and Methods

A total of 1,892 individuals aged 40–79 years without diabetes at baseline were prospectively followed up for 14 years. The glucose tolerance status of participants was defined by a 75‐g oral glucose tolerance test with the 1998 World Health Organization criteria. Dietary fiber intake was estimated by a semiquantitative food frequency questionnaire and divided to quintile levels separately by sex. A Cox proportional hazards model was applied for computing the hazard ratios and their 95% confidence intervals for the incidence of diabetes.

Results

During the follow‐up period, 280 participants had developed diabetes. The age‐adjusted cumulative diabetes incidence decreased significantly with higher total dietary fiber intake (P‐for trend = 0.01). Participants in the highest quintile of total dietary fiber intake had a 0.53‐fold (95% confidence interval 0.31–0.90) lower risk of developing diabetes than those in the lowest quintile after for the adjustment with potential confounding factors. Total dietary fiber intake showed a moderate positive correlation to the intake of soybean and soybean products, green vegetables, and other vegetables. Similar associations with diabetes and food sources were observed for both of the soluble and insoluble dietary fiber intake.

Conclusions

The present study showed that higher dietary fiber intake was associated with a lower risk of type 2 diabetes in a general Japanese population. The intake of high dietary fiber foods might be useful for diabetes prevention.

Long-term dietary fiber intake and risk of chronic obstructive pulmonary disease: a prospective cohort study of women

PURPOSE

Until now, only two prospective cohort studies have investigated dietary fiber intake in relation to risk of chronic obstructive pulmonary disease (COPD), but neither examined long-term fiber intake. Both studies reported that total fiber intake was associated with decreased COPD risk; however, results for specific fiber sources were inconsistent. Thus, we prospectively evaluated the association between baseline and long-term intake of dietary fiber and COPD risk in a population-based prospective cohort of 35,339 Swedish women.

METHODS

Dietary fiber intake was assessed in 1987 and 1997 with a food frequency questionnaire. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During follow-up (2002-2014), 1557 COPD cases were identified via linkage to the Swedish National Patient Register. Long-term high dietary fiber intake (≥ 26.5 vs. < 17.6 g/day) was associated with a 30% (95% CI 17-41%) lower risk of COPD. For specific fiber sources, cereal (≥ 16.3 vs. < 9.4 g/day; HR 0.67, 95% CI 0.55-0.81) and fruit fiber (≥ 7.6 vs. < 2.6 g/day; HR 0.65, 95% CI 0.5-0.81), but not vegetable fiber intake (≥ 5.4 vs. < 2.2 g/day; HR 1.03, 95% CI 0.81-1.28) were associated with lower COPD risk. Current and ex-smokers with low long-term total fiber intake (< 17.6 g/day) compared to never smokers with high intake (≥ 26.5 g/day) had a 33-fold (95% CI 23.6-46.6) and tenfold (95% CI 7.0-16.3), respectively, higher risk of COPD.

CONCLUSIONS

Our findings indicate that high fiber intake is a modifiable lifestyle factor which may decrease COPD risk primarily in current and ex-smokers.

Associations between consumption of dietary fibers and the risk of cardiovascular diseases, cancers, type 2 diabetes, and mortality in the prospective NutriNet-Santé cohort

BACKGROUND

Mounting evidence, yet with varying levels of proof, suggests that dietary fibers (DFs) may exert a protective role against various chronic diseases, but this might depend on the DF type and source.

OBJECTIVES

Our objectives were to assess the associations between the intake of DFs of different types [total (TDF), soluble (SF), insoluble (IF)] and from different sources (fruits, vegetables, whole grains, legumes, potatoes and tubers) and the risk of cardiovascular diseases (CVDs), cancer, type 2 diabetes (T2D), and mortality in the large-scale NutriNet-Santé prospective cohort (2009-2019).

METHODS

Overall, 107,377 participants were included. Usual DF intake was estimated from validated repeated 24-h dietary records over the first 2 y following inclusion in the cohort. Associations between sex-specific quintiles of DF intake and the risk of chronic diseases and mortality were assessed using multiadjusted Cox proportional hazards models.

RESULTS

T2D risk was inversely associated with TDFs [HR for quintile 5 compared with quintile 1: 0.59 (95% CI: 0.42, 0.82), P-trend <0.001], SFs [HR: 0.77 (0.56, 1.08); P-trend = 0.02], and IFs [HR: 0.69 (0.50, 0.96); P-trend = 0.004]. SFs were associated with a decreased risk of CVD [HR: 0.80 (0.66, 0.98); P-trend = 0.01] and colorectal cancer [HR: 0.41 (0.21, 0.79); P-trend = 0.01]. IFs were inversely associated with mortality from cancer or CVDs [HR: 0.65 (0.45, 0.94); P-trend = 0.02]. TDF intake was associated with a decreased risk of breast cancer [HR:: 0.79 (0.54, 1.13); P-trend = 0.04]. DF intake from fruit was associated with the risk of several chronic diseases.

CONCLUSIONS

Our results suggest that DF intake, especially SFs and DFs from fruits, was inversely associated with the risk of several chronic diseases and with mortality. Further studies are needed, involving different types and sources of fiber. Meanwhile, more emphasis should be put on DFs in public health nutrition policies, as DF intake remains below the recommended levels in many countries. This trial was registered at clinicaltrials.gov as NCT03335644.

Fruit and vegetable intake is inversely associated with type 2 diabetes in Chinese women: results from the China Health and Nutrition Survey

This study aimed to evaluate the associations between fruit and vegetable (FV) intake and the risk of prediabetes or type 2 diabetes (T2D). It is a cross-sectional study that involved 6802 participants aged 18-65 years. Dietary intake and other variables were assessed by questionnaires. The prevalence of prediabetes and T2D was ascertained by self-report and analyses of fasting blood samples. In the multiple logistic regression models, FV intake was negatively associated the risk of T2D in women (OR = 0.45, 95% CI: 0.28, 0.71), whereas no such association was observed in men (OR = 0.98, 95% CI: 0.65, 1.47). Furthermore, FV consumption was inversely associated with prediabetes risk in men and women. Results suggested that higher intake of FV was associated with a decreased risk of T2D or prediabetes in Chinese women and a reduced risk of prediabetes in men only.

Carbohydrate quality, glycemic index, glycemic load and cardiometabolic risks in the US, Europe and Asia: A dose-response meta-analysis

BACKGROUND AND AIMS

Despite the proven evidence of high glycemic index (GI) and glycemic load (GL) diets to increase cardiometabolic risks, knowledge about the meta-evidence for carbohydrate quality within world geographic regions is limited. We conducted a meta-analysis to synthesize the evidence of GI/GL studies and carbohydrate quality, gathering additional exposures for carbohydrate, high glycemic carbohydrate, total dietary fiber, and cereal fiber and risks for type 2 diabetes (T2DM), coronary heart disease (CHD), stroke, and mortality, grouped into the US, Europe, and Asia. Secondary aims examined cardiometabolic risks in overweight/obese individuals, by sex, and dose-response dietary variable trends.

METHODS AND RESULTS

40-prospective observational studies from 4-Medline bibliographical databases (Ovid, PubMed, EBSCOhost, CINAHL) were search up to November 2019. Random-effects hazard ratios (HR) and 95% confidence intervals (CI) for highest vs. lowest categories and continuous form combined were reported. Heterogeneity (I²>50%) was frequent in US GI/GL studies due to differing study characteristics. Increased risks ((HR_GI,T2DM,US=1.14;CI:1.06,1.21), HR_GL,T2DM,US=1.02 (1.01, 1.03)), HR_GI,T2DM,Asia=1.25;1.02,1.53), and HR_GL,T2DM,Asia=1.37 (1.17, 1.60)) were associated with cardiometabolic diseases. GI/GL in overweight/obese females had the strongest magnitude of risks in US-and Asian studies. Total dietary fiber (HR_T2DM,US = 0.92;0.88,0.96) and cereal fiber (HR_T2DM,US = 0.83;0.77,0.90) decreased risk of developing T2DM. Among females, we found protective dose-response risks for total dietary fiber (HR_{5g-total-dietary-fiber,T2DM,US} = 0.94;0.92,0.97)_, but cereal fiber showed better ability to lower T2DM risk (HR_{5g-cereal-fiber},_T2DM,US = 0.67;0.60,0.74). Total dietary-and cereal fibers' dose-response effects were nullified by GL, but not so for cereal fiber with GI.

CONCLUSIONS

Overweight/obese females could shift their carbohydrate intake for higher cereal fiber to decrease T2DM risk, but higher GL may cancel-out this effect.

Vitamin D Status, Fiber Intake, and Type 2 Diabetes in U.S. Adults

Vitamin D and fiber intake are nutritional factors that could affect the development of type 2 diabetes (T2D), potentially by reducing insulin resistance. Therefore, we hypothesized that the influence of vitamin D on T2D might depend on fiber intake. This study investigated the association between vitamin D status and T2D according to fiber intake. The present study analyzed data from 9,656 American adults (≥20 years old) who participated in the National Health and Nutrition Examination Survey (NHANES) 2007-2010. The serum concentration of 25-hydroxyvitamin D [25(OH)D] was used as a biomarker for vitamin D status. The T2D classification was based on two criteria: T2D^a was identified using only self-reported questionnaire data and T2D^b was identified based on both survey and laboratory data. The deficient vitamin D status (<50 nmol/L) was used as the reference group. After controlling for sociodemographic, behavioral, and dietary factors, the odds ratios (ORs) were 0.72 (95% confidence interval [CI]: 0.58, 0.90) for T2D^a and 0.60 (0.50, 0.80) for T2D^b in the sufficient vitamin D status (≥75 nmol/L). Furthermore, the total vitamin D concentration exhibited dose-dependent associations with lower OR values for T2D^a (P for trend = .005) and T2D^b (P for trend <.001). Among participants with high-fiber intake, the OR values for T2D^b were 0.60 (95% CI: 0.42, 0.90) at suboptimal vitamin D status and 0.49 (95% CI: 0.31, 0.77) at sufficient vitamin D status. Moreover, the significant dose-dependent association persisted in the high-fiber-intake subgroup (P for trend = .004). Therefore, combining vitamin D plus high-fiber intake would help reduce the prevalence of diabetes, although the interaction analysis results were not statistically significant.

Bound Phenolics Ensure the Antihyperglycemic Effect of Rice Bran Dietary Fiber in db/db Mice via Activating the Insulin Signaling Pathway in Skeletal Muscle and Altering Gut Microbiota

Whole-grain dietary fiber intake is beneficial in the prevention of metabolic syndrome. Considering rich in bound phenolics being a special characteristic of whole-grain dietary fiber, the aim of this study was to evaluate the effects of the presence or absence of bound phenolics in rice bran dietary fiber (RBDF) on regulating glucose metabolism in diabetic db/db mice. In comparison to phenolics-removed RBDF (PR-RBDF) intervention without an antihyperglycemic effect, RBDF and formulated RBDF (F-RBDF, obtained by mixing PR-RBDF and hydrolyzed-bound phenolics) significantly reduced fasting blood glucose levels after 1 and 5 weeks of interventions, respectively. The presence of bound phenolics interventions could activate the IRS1/AKT/GLUT4 insulin signaling pathway in skeletal muscle and alter gut microbiota by modulating gut microbiota dysbiosis and enriching the butyric-acid-producing bacteria genera of the families Lachnospiraceae and Ruminococcaceae, thus leading to the reduction of blood glucose levels. These findings indicate that bound phenolics ensure the antihyperglycemic effect of RBDF.

Diet and liver cancer risk: a narrative review of epidemiological evidence

Primary liver cancer is the third leading cause of cancer-related death worldwide. Most patients are diagnosed at late stages with poor prognosis; thus, identification of modifiable risk factors for primary prevention of liver cancer is urgently needed. The well-established risk factors of liver cancer include chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV), heavy alcohol consumption, metabolic diseases such as obesity and diabetes, and aflatoxin exposure. However, a large proportion of cancer cases worldwide cannot be explained by current known risk factors. Dietary factors have been suspected as important, but dietary aetiology of liver cancer remains poorly understood. In this review, we summarised and evaluated the observational studies of diet including single nutrients, food and food groups, as well as dietary patterns with the risk of developing liver cancer. Although there are large knowledge gaps between diet and liver cancer risk, current epidemiological evidence supports an important role of diet in liver cancer development. For example, exposure to aflatoxin, heavy alcohol drinking and possibly dairy product (not including yogurt) intake increase, while intake of coffee, fish and tea, light-to-moderate alcohol drinking and several healthy dietary patterns (e.g. Alternative Healthy Eating Index) may decrease liver cancer risk. Future studies with large sample size and accurate diet measurement are warranted and need to consider issues such as the possible aetiological heterogeneity between liver cancer subtypes, the influence of chronic HBV or HCV infection, the high-risk populations (e.g. cirrhosis) and a potential interplay with host gut microbiota or genetic variations.

Dietary Carbohydrate Constituents Related to Gut Dysbiosis and Health

Recent studies report that microbiota in the human intestine play an important role in host health and that both long- and short-term diets influence gut microbiota. These findings have fueled interest in the potential of food to promote health by shaping the intestinal microbiota. Despite the fact that large populations in Asia consume high quantities of carbohydrates, such diets have been ignored in comparison to the attention received by Western diets containing high quantities of fat and animal protein. We gathered data that suggest an association between imbalanced high-carbohydrate intake and gut microbiota and host health. In this review, we identify not only the effect of total carbohydrates on the intestinal microbiota specifically and the health of their hosts in general, but also how specific types of carbohydrates influence both factors.

The Effect of Isolated and Synthetic Dietary Fibers on Markers of Metabolic Diseases in Human Intervention Studies: A Systematic Review

Observational studies provide strong evidence for the health benefits of dietary fiber (DF) intake; however, human intervention studies that supplement isolated and synthetic DFs have shown inconsistent results. Therefore, we conducted a systematic review to summarize the effects of DF supplementation on immunometabolic disease markers in intervention studies in healthy adults, and considered the role of DF dose, DF physicochemical properties, intervention duration, and the placebo used. Five databases were searched for studies published from 1990 to 2018 that assessed the effect of DF on immunometabolic markers. Eligible studies were those that supplemented isolated or synthetic DFs for ≥2 wk and reported baseline data to assess the effect of the placebo. In total, 77 publications were included. DF supplementation reduced total cholesterol (TC), LDL cholesterol, HOMA-IR, and insulin AUC in 36-49% of interventions. In contrast, <20% of the interventions reduced C-reactive protein (CRP), IL-6, glucose, glucose AUC, insulin, HDL cholesterol, and triglycerides. A higher proportion of interventions showed an effect if they used higher DF doses for CRP, TC, and LDL cholesterol (40-63%), viscous and mixed plant cell wall DFs for TC and LDL cholesterol (>50%), and longer intervention durations for CRP and glucose (50%). Half of the placebo-controlled studies used digestible carbohydrates as the placebo, which confounded findings for IL-6, glucose AUC, and insulin AUC. In conclusion, interventions with isolated and synthetic DFs resulted mainly in improved cholesterol concentrations and an attenuation of insulin resistance, whereas markers of dysglycemia and inflammation were largely unaffected. Although more research is needed to make reliable recommendations, a more targeted supplementation of DF with specific physicochemical properties at higher doses and for longer durations shows promise in enhancing several of its health effects.

Association of Intake of Whole Grains and Dietary Fiber With Risk of Hepatocellular Carcinoma in US Adults

Importance

Increased intake of whole grain and dietary fiber has been associated with lower risk of insulin resistance, hyperinsulinemia, and inflammation, which are known predisposing factors for hepatocellular carcinoma (HCC). Therefore, we hypothesized that long-term intake of whole grains and dietary fiber may be associated with lower risk of HCC.

Objective

To assess the associations of whole grain and dietary fiber intake with the risk of HCC.

Design, Setting, and Participants

Cohort study of the intake of whole grains, their subcomponents (bran and germ), and dietary fiber (cereal, fruit, and vegetable) in 125 455 participants from 2 cohorts from the Nurses' Health Study and the Health Professionals Follow-up Study.

Exposures

Intake of whole grains, their subcomponents (bran and germ), and dietary fiber (cereal, fruit, and vegetable) were collected and updated almost every 4 years using validated food frequency questionnaires.

Main Outcomes and Measures

Multivariable hazard ratios (HRs) and 95% CIs were estimated using Cox proportional hazards regression model after adjusting for most known HCC risk factors.

Results

After an average follow-up of 24.2 years, we identified 141 patients with HCC among 125 455 participants (77 241 women and 48 214 men (mean [SD] age, 63.4 [10.7] years). Increased whole grain intake was significantly associated with lower risk of HCC (the highest vs lowest tertile intake: HR, 0.63; 95% CI, 0.41-0.96; P = .04 for trend). A nonsignificant inverse HCC association was observed for total bran (HR, 0.70; 95% CI, 0.46-1.07; P = .11 for trend), but not for germ. Increased intake of cereal fiber (HR, 0.68; 95% CI, 0.45-1.03; P = .07 for trend), but not fruit or vegetable fiber, was associated with a nonsignificant reduced risk of HCC.

Conclusions and Relevance

Increased intake of whole grains and possibly cereal fiber and bran could be associated with reduced risk of HCC among adults in the United States. Future studies that carefully consider hepatitis B and C virus infections are needed to replicate our findings, to examine these associations in other racial/ethnic or high-risk populations, and to elucidate the underlying mechanisms.

Effects of insoluble and soluble fibers isolated from barley on blood glucose, serum lipids, liver function and caecal short-chain fatty acids in type 2 diabetic and normal rats

Large prospective cohort studies suggested an important role of cereal insoluble fiber in the prevention and management of type 2 diabetes, which challenge the traditional view that viscosity and solubility are the main driving factors for these beneficial effects of dietary fiber. To evaluate the anti-diabetic effects of insoluble- (BIF) and soluble fibers (BSF) enzymatically isolated from barley, a conventional rat model and a type 2 diabetes rat model were used. Our results showed that 4-week treatment of BIF or BSF effectively reduced FBG in the diabetic condition, with caecal level of propionic acid and minor SCFAs increased by BIF and that of butyric acid and insulin sensitivity improved by BSF, respectively. The two treatments further ameliorated liver function, judged by the recovered serum level of ALT, albumin and total protein levels. BIF and BSF also increased HDL-C and decreased serum MDA. In normal rats, BIF and BSF showed a hypolipidaemic effect in triglycerides and LDL-C, reduced body weight and enhanced the caecal production of minor SCFAs. Furthermore, the two treatments reduced the caecal level of butyric acid while BSF increased that of propionic acid. In conclusion, BIF could exert anti-diabetic effects that might via a different mechanism from BSF.

Rice and Prevention of Type 2 Diabetes: Narrative Review of Epidemiologic Evidene

Inspite that rice is a main staple and heaviliy consumed in most of Asian populations, health effect of rice has been less examined in nutritional epidemiologic studies compared to those of foods such as fruits, vegetables, meats and fish. Some recent meta-analyses that collected prospective cohort studies reported the associations between rice intake and incidence of and mortality from some chronic diseases especially type 2 diabetes. Concerning type 2 diabetes, the results are remarkably different between white (polished) rice and brown (unpolished) rice: the former increased and the latter decreased the risk. This difference may partly be explained by the different types and amounts of dietary fiber and different scores of dietary glycemic index. However, the results on dietary fiber and dietary glycemic index were not necessarily consistent. Indirect effect of rice intake has been examined through the studies on association of dietary patterns and breakfast skipping to type 2 diabetes. However, most of the results were inconclusive. Simple and straightforward judgement on the effect of rice to type 2 diabete should be avoided, and more nutritional epidemiologic studies with high research quality, including basic studies on dietary assessment, are needed, especially in Asian populations.

Dietary manipulation and testosterone replacement therapy may explain changes in body composition after spinal cord injury: A retrospective case report

BACKGROUND

Reduced level of physical activity, high-fat diet and skeletal muscle atrophy are key factors that are likely to contribute to deleterious changes in body composition and metabolic following spinal cord injury (SCI). Reduced caloric intake with lowering percentage macronutrients of fat and increasing protein intake may likely to improve body composition parameters and decrease ectopic adiposity after SCI.

AIM

To highlight the effects of dietary manipulation and testosterone replacement therapy (TRT) on body composition after SCI

METHODS

A 31-year-old male with T5 SCI was administered transdermal TRT daily for 16 wk. Caloric intake and percentage macronutrients were analyzed using dietary recalls. Magnetic resonance imaging and dual-energy x-ray absorptiometry were used to measure changes in body composition.

RESULTS

Caloric intake and fat percentage were reduced by 445 kcal/d and 6.5%, respectively. Total body weight decreased by 8%, body fat decreased by 29%, and lean mass increased by 7%. Thigh subcutaneous adipose tissue cross-sectional area was reduced by 31%.

CONCLUSION

Manipulation of caloric intake, fat percentage, and protein percentage may have influenced body composition after SCI.

Metabolic Effects of Resistant Starch Type 2: A Systematic Literature Review and Meta-Analysis of Randomized Controlled Trials

Published evidence exploring the effects of dietary resistant starch (RS) on human cardiometabolic health is inconsistent. This review aimed to investigate the effect of dietary RS type 2 (RS2) supplementation on body weight, satiety ratings, fasting plasma glucose, glycated hemoglobin (HbA1c), insulin resistance and lipid levels in healthy individuals and those with overweight/obesity, the metabolic syndrome (MetS), prediabetes or type 2 diabetes mellitus (T2DM). Five electronic databases were searched for randomized controlled trials (RCTs) published in English between 1982 and 2018, with trials eligible for inclusion if they reported RCTs involving humans where at least one group consumed ≥ 8 g of RS2 per day and measured body weight, satiety, glucose and/or lipid metabolic outcomes. Twenty-two RCTs involving 670 participants were included. Meta-analyses indicated that RS2 supplementation significantly reduced serum triacylglycerol concentrations (mean difference (MD) = -0.10 mmol/L; 95% CI -0.19, -0.01, P = 0.03) in healthy individuals (n = 269) and reduced body weight (MD = -1.29 kg; 95% CI -2.40, -0.17, P = 0.02) in people with T2DM (n = 90). However, these outcomes were heavily influenced by positive results from a small number of individual studies which contradicted the conclusions of the majority of trials. RS2 had no effects on any other metabolic outcomes. All studies ranged from 1-12 weeks in duration and contained small sample sizes (10-60 participants), and most had an unclear risk of bias. Short-term RS2 supplementation in humans is of limited cardiometabolic benefit.

Identification of Dietary Patterns Associated with Incidence of Hyperglycemia in Middle-Aged and Older Korean Adults

Little is known about the association between dietary patterns and hyperglycemia incidence among Korean adults. Hence, we aimed to prospectively investigate the major dietary patterns associated with hyperglycemia among middle-aged and older Korean adults. In total, 55,457 adults (18,292 men and 37,165 women) aged 40 to 79 years, who were previously enrolled in the Health Examinee Study of the Korean Genome and Epidemiology Study and had no history of type 2 diabetes mellitus (T2DM) or cancer at baseline, were included. Dietary patterns were identified by a factor analysis based on dietary data, which were assessed at baseline using a validated food-frequency questionnaire. Participants were classified as having hyperglycemia if fasting blood glucose levels were ≥126 mg/dL or physician diagnosed T2DM during follow-up. Multivariable Cox proportional hazard models were used to examine the associations between each dietary pattern and future hyperglycemia risk after adjusting for potential confounders. After a mean follow-up of 4.9 years, 2574 new cases of hyperglycemia were identified. Using a factor analysis, four distinct dietary patterns were identified: “prudent;” “fatty fish, meat, and flour-based food;” “coffee and sweets;” and “whole grain (men)” or “white rice (women).” The “prudent” pattern was inversely associated with hyperglycemia risk only in women (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.63–0.89; p for trend = 0.0003). Conversely, women in the highest quintile of the “fatty fish, meat, and flour-based food” pattern showed an increased risk of hyperglycemia (HR, 1.22; 95% CI, 1.03–1.44; p for trend = 0.0210) compared with those in the lowest quintile. The “coffee and sweets” and “white rice” patterns were not associated with hyperglycemia risk in women. The dietary patterns observed in men had no associations with hyperglycemia incidence. Our findings suggest that a diet rich in vegetables, mushrooms, seaweeds, fruits, and soy products and low in fatty fish and high-fat meat may potentially play a protective role in T2DM development with sex differences in middle-aged and older Korean adults.

Dietary Approaches to Stop Hypertension (DASH): potential mechanisms of action against risk factors of the metabolic syndrome

The metabolic syndrome is a cluster of disorders dominated by abdominal obesity, hypertriacylglycerolaemia, low HDL-cholesterol, high blood pressure and high fasting glucose. Diet modification is a safe and effective way to treat the metabolic syndrome. Dietary Approaches to Stop Hypertension (DASH) is a dietary pattern rich in fruits, vegetables and low-fat dairy products, and low in meats and sweets. DASH provides good amounts of fibre, K, Ca and Mg, and limited quantities of total fat, saturated fat, cholesterol and Na. Although DASH was initially designed for the prevention or control of hypertension, using a DASH diet has other metabolic benefits. In the present review, the effect of each dietary component of DASH on the risk factors of the metabolic syndrome is discussed. Due to limited fat and high fibre and Ca content, individuals on the DASH diet are less prone to overweight and obesity and possess lower concentrations of total and LDL-cholesterol although changes in TAG and HDL-cholesterol have been less significant and available evidence in this regard is still inconclusive. Moreover, high amounts of fruit and vegetables in DASH provide great quantities of K, Mg and fibre, all of which have been shown to reduce blood pressure. K, Mg, fibre and antioxidants have also been effective in correcting glucose and insulin abnormalities. Evidence is provided from cross-sectional investigations, cohort studies and randomised controlled trials, and, where available, from published meta-analyses. Mechanisms are described according to human studies and, in the case of a lack of evidence, from animal and cell culture investigations.

Effect of different dietary patterns on glycemic control in individuals with type 2 diabetes mellitus: A systematic review

Different dietary patterns have been positively related to the glycemic control of individuals with type 2 diabetes mellitus. However, consensual dietary pattern for these individuals is not established. We aimed to evaluate the effects of adopting different dietary patterns on glycemic control markers of individuals with type 2 diabetes mellitus. PubMed, Scopus, MEDLINE, Lilacs, Open Thesis and Google Scholar databases were searched using the Medical Subject Headings and terms related to dietary pattern and glycemic control in individuals with type 2 diabetes mellitus. Interventional studies with adults of this population without diabetes-related complications, presenting data on percentage of glycated hemoglobin, and dietary patterns were included. In vitro, animal, reviews, observational, and studies with children, adolescents, pregnant and breastfeeding women were excluded. The time of adoption dietary patterns ranged from eight weeks to four years in randomized clinical trials, and six months in the cohort study. Vegetarian, vegan, Mediterranean, and Dietary Approaches to Stop Hypertension dietary patterns reduced 0.8% on average of percentage of glycated hemoglobin, considering all included studies. It was also observed reduction in fasting glycemia and improvement in Homeostasis Model Assessment of Insulin Sensitivity. However, more randomized clinical trials are required for a full elucidation of these questions.

A Threshold of Objectively-Assessed Daily Sedentary Time for All-Cause Mortality in Older Adults: A Meta-Regression of Prospective Cohort Studies

Background: This meta-analysis aimed to estimate the shape of the dose-response association between objectively-assessed daily sedentary time (ST) and all-cause mortality, and to explore whether there is a threshold of ST above which there is an increase in mortality risk in older adults. Methods: Searches for prospective cohort studies providing effect estimates of daily ST (exposure) on all-cause mortality (outcome) were undertaken in five databases up to 31 March 2019. A random-effects meta-regression model was conducted to quantify the dose-response relationship between daily ST and all-cause mortality. Sensitivity analyses were also performed to test the stability of the results. Results: Our analysis of pooled data from 11 eligible studies did not reveal a consistent shape of association between ST and mortality. After excluding three studies with potential confounding bias, there was a log-linear dose-response relationship between daily ST and all-cause mortality. Overall, higher amounts of time spent in sedentary behaviors were associated with elevated mortality risks in older adults. Visual assessments of dose-response relationships based on meta-regression analyses indicated that increased mortality risks became significant when total ST exceeded approximately 9 h/day. Conclusions: Based on a limited number of studies, this meta-analysis provides a starting point for considering a cut-off of daily sedentary time, suggesting older adults spend less time in daily sitting.

Low intakes of dietary fiber and magnesium are associated with insulin resistance and hyperandrogenism in polycystic ovary syndrome: A cohort study

BACKGROUND

Women with polycystic ovary syndrome (PCOS) often have insulin resistance (IR) which may be worsened by obesity. The roles of dietary intake and activity are unclear. Our objectives were to determine whether (a) high caloric intake or inactivity explains obesity in PCOS, and (b) dietary composition is associated with PCOS phenotypes.

METHODS

Eighty-seven women with PCOS and 50 women without PCOS participated in this cohort study at a reproductive medicine center. Data collected included 3-day food and physical activity records, anthropometrics, and metabolic and hormonal assays.

RESULTS

Women with PCOS had increased body mass index (BMI) but similar caloric intake and activity to women without PCOS. There were no differences in protein, carbohydrates, fat, or glycemic load consumption, but women with PCOS consumed less fiber (medians: 19.6 vs. 24.7 g) and less magnesium (medians: 238.9 vs. 273.9 mg). In women with PCOS, those with IR consumed less fiber, less magnesium, and greater glycemic load than those without IR (medians: 18.2 vs. 22.1 g, 208.4 vs. 264.5 mg, 89.6 vs. 83.5). Fiber intake of women with PCOS was negatively correlated with IR, fasting insulin, glucose tolerance, testosterone, and dehydroepiandrosterone sulfate. Magnesium intake was negatively correlated with IR, C-reactive protein, and testosterone, but positively correlated with HDL cholesterol. Fiber intake and BMI accounted for 54.0% of the variance observed in IR.

CONCLUSIONS

Obesity in women with PCOS could not be explained by overeating or inactivity. Increasing dietary fiber and magnesium intakes may assist in reducing IR and hyperandrogenemia in women with PCOS.

Dietary fiber sources and human benefits: The case study of cereal and pseudocereals

Dietary fiber (DF) includes the remnants of the edible part of plants and analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the human large intestine. DF can be classified into two main groups according to its solubility, namely insoluble dietary fiber (IDF) that mainly consists on cell wall components, including cellulose, some hemicelluloses, lignin and resistant starch, and soluble dietary fiber (SDF) that consists of non-cellulosic polysaccharides as non-digestible oligosaccharides, arabinoxylans (AX), β-glucans, some hemicelluloses, pectins, gums, mucilages and inulin. The intake of DF is associated with health benefits. IDF can contribute to the normal function of the intestinal tract and it has an important role in the prevention of colonic diverticulosis and constipation. SDF is extensively fermented by gut microbiota and it is associated with carbohydrate and lipid metabolism, with important health benefits due to its hypocholesterolemic properties. Due to these nutritional and health properties, DF is widely used as functional ingredients in food industry, being whole grain cereals, pulses, fruits and vegetables the main sources of DF. Also some synthetic sources are employed, namely polydextrose, hydroxypropyl methylcellulose or cyclodextrins. The DF content of cereals varies depending on cultivars, their botanical components (pericarp, emdosperm and germ) and the processing conditions they have undergone (baking, extrusion, etc.). In cereal grains, AX are the predominant non-cellulose DF polysaccharides followed by cellulose and β-glucans, while in pseudocereals, pectins are quantitatively predominant.

Modulation of the Gut Microbiota by Resistant Starch as a Treatment of Chronic Kidney Diseases: Evidence of Efficacy and Mechanistic Insights

Chronic kidney disease (CKD) has been associated with changes in gut microbial ecology, or "dysbiosis," which may contribute to disease progression. Recent studies have focused on dietary approaches to favorably alter the composition of the gut microbial communities as a treatment method in CKD. Resistant starch (RS), a prebiotic that promotes proliferation of gut bacteria such as Bifidobacteria and Lactobacilli, increases the production of metabolites including short-chain fatty acids, which confer a number of health-promoting benefits. However, there is a lack of mechanistic insight into how these metabolites can positively influence renal health. Emerging evidence shows that microbiota-derived metabolites can regulate the incretin axis and mitigate inflammation via expansion of regulatory T cells. Studies from animal models and patients with CKD show that RS supplementation attenuates the concentrations of uremic retention solutes, including indoxyl sulfate and p-cresyl sulfate. Here, we present the current state of knowledge linking the microbiome to CKD, we explore the efficacy of RS in animal models of CKD and in humans with the condition, and we discuss how RS supplementation could be a promising dietary approach for slowing CKD progression.

Association of dietary fiber intake with hyperuricemia in U.S. adults

Current evidence on the relationship between dietary fiber intake and risk of hyperuricemia is limited.

Differential associations between diet and prediabetes or diabetes in the KORA FF4 study

Type 2 diabetes mellitus (T2DM) is a global public health epidemic. Diet and lifestyle changes have been demonstrated as effective measures in managing T2DM and preventing or delaying the progression from prediabetes to diabetes, yet the relationship between diet, prediabetes and diabetes is still not entirely clear. The present study aimed to further elucidate the relationship between diet, diabetes and especially prediabetes. A total of 1542 participants of the cross-sectional, population-based Cooperative Health Research in the Region of Augsburg (KORA) FF4 study (2013/2014) were included in this analysis. Dietary intake was derived using a method combining information from a FFQ and repeated 24-h food lists. Glucose tolerance status was assessed via oral glucose tolerance tests in all participants without a previous physician-confirmed diagnosis of T2DM, and was classified according to the 2003 American Diabetes Association criteria. Crude and fully adjusted multinomial logistic regression models were fitted to examine associations between diet and prediabetes, undetected diabetes mellitus (UDM) and prevalent T2DM. After adjusting for major covariates, fruit was significantly inversely and total meat, processed meat, sugar-sweetened beverages and moderate alcohol significantly associated with UDM and/or prevalent diabetes. Sex-specific analyses showed that in men, coffee was significantly inversely (OR 0·80; 95 % CI 0·67, 0·96) and heavy alcohol significantly (OR 1·84; 95 % CI 1·14, 2·95) associated with prediabetes. Our findings on diet and T2DM are consistent with current literature, while our results regarding coffee, heavy alcohol consumption and prediabetes highlight new possible targets for primary prevention of the derangement of glucose homeostasis.

Whole Fruits and Fruit Fiber Emerging Health Effects

Less than 10% of most Western populations consume adequate levels of whole fruits and dietary fiber with typical intake being about half of the recommended levels. Evidence of the beneficial health effects of consuming adequate levels of whole fruits has been steadily growing, especially regarding their bioactive fiber prebiotic effects and role in improved weight control, wellness and healthy aging. The primary aim of this narrative review article is to examine the increasing number of health benefits which are associated with the adequate intake of whole fruits, especially fruit fiber, throughout the human lifecycle. These potential health benefits include: protecting colonic gastrointestinal health (e.g., constipation, irritable bowel syndrome, inflammatory bowel diseases, and diverticular disease); promoting long-term weight management; reducing risk of cardiovascular disease, type 2 diabetes and metabolic syndrome; defending against colorectal and lung cancers; improving odds of successful aging; reducing the severity of asthma and chronic obstructive pulmonary disease; enhancing psychological well-being and lowering the risk of depression; contributing to higher bone mineral density in children and adults; reducing risk of seborrheic dermatitis; and helping to attenuate autism spectrum disorder severity. Low whole fruit intake represents a potentially more serious global population health threat than previously recognized, especially in light of the emerging research on whole fruit and fruit fiber health benefits.