Dietary fiber supplements: effects in obesity and metabolic syndrome and relationship to gastrointestinal functions

Secondary Metabolites, Dietary Fiber and Conjugated Fatty Acids as Functional Food Ingredients against Overweight and Obesity

Obesity is a common serious health problem leading to many serious health disorders. This phenomenon is defined as the over-storage of lipids in adipose tissue that occurs when there is an imbalance between the energy intake and energy used. During obesity, many metabolic alterations occur that can damage several organs, such as vascular or skeletal muscle resulting in the dysfunction of these tissues. In this review, we will discuss molecular genetics and causes of obesity, some of the disorders related to human obesity as well as anti-obesity tool. An interesting solution to the obesity problem is natural substances, revealing anti-obesity activity, as well as functional food enriched with aforementioned substances. Functional foods are products exhibiting a potentially positive effect on health beyond basic nutrition. They contain well-known biologically active natural compounds, which promote optimal health and reduce the risk of many diseases, including obesity.

Dietary Fibre as a Unifying Remedy for the Whole Spectrum of Obesity-Associated Cardiovascular Risk

Obesity is a pandemic carrying the heavy burden of multiple and serious co-morbidities including metabolic syndrome, type 2 diabetes and cardiovascular diseases. The pathophysiological processes leading to the accumulation of body fat slowly evolve to fat accumulation in other body compartments than subcutaneous tissue. This abnormal fat deposition determines insulin resistance which in turn causes blood glucose and lipid metabolism derangement, non-alcoholic fatty liver disease, hypertension, and metabolic syndrome. All these conditions contribute to increase the cardiovascular risk of obese people. Several randomized clinical trials demonstrated that moderate weight loss (5⁻10%) in obese patients improves obesity-related metabolic risk factors and coexisting disorders. Therefore, nutritional strategies able to facilitate weight management, and in the meantime positively influence obesity-associated cardiovascular risk factors, should be implemented. To this aim, a suitable option could be dietary fibres that may also act independently of weight loss. The present narrative review summarizes the current evidence about the effects of dietary fibres on weight management in obese people. Moreover, all of the different cardiovascular risk factors are individually considered and evidence on cardiovascular outcomes is summarized. We also describe the plausible mechanisms by which different dietary fibres could modulate cardio-metabolic risk factors. Overall, despite both epidemiological and intervention studies on weight loss that show statistically significant but negligible clinical effects, dietary fibres seem to have a beneficial impact on main pathophysiological pathways involved in cardiovascular risk (i.e., insulin resistance, renin-angiotensin, and sympathetic nervous systems). Although the evidence is not conclusive, this suggests that fibre would be a suitable option to counteract obesity-related cardio-metabolic diseases also independently of weight loss. However, evidence is not consistent for the different risk factors, with clear beneficial effects shown on blood glucose metabolism and Low Density Lipoprotein (LDL) cholesterol while there is fewer, and less consistent data shown on plasma triglyceride and blood pressure. Ascribing the beneficial effect of some foods (i.e., fruits and vegetables) solely to their fibre content requires more investigation on the pathophysiological role of other dietary components, such as polyphenols.

Plant versus animal based diets and insulin resistance, prediabetes and type 2 diabetes: the Rotterdam Study

Vegan or vegetarian diets have been suggested to reduce type 2 diabetes (T2D) risk. However, not much is known on whether variation in the degree of having a plant-based versus animal-based diet may be beneficial for prevention of T2D. We aimed to investigate whether level of adherence to a diet high in plant-based foods and low in animal-based foods is associated with insulin resistance, prediabetes, and T2D. Our analysis included 6798 participants (62.7 ± 7.8 years) from the Rotterdam Study (RS), a prospective population-based cohort in the Netherlands. Dietary intake data were collected with food-frequency questionnaires at baseline of three sub-cohorts of RS (RS-I-1: 1989–1993, RS-II-1: 2000–2001, RS-III-1: 2006–2008). We constructed a continuous plant-based dietary index (range 0–92) assessing adherence to a plant-based versus animal-based diet. Insulin resistance at baseline and follow-up was assessed using homeostasis model assessment of insulin resistance (HOMA-IR). Prediabetes and T2D were collected from general practitioners’ records, pharmacies’ databases, and follow-up examinations in our research center until 2012. We used multivariable linear mixed models to examine association of the index with longitudinal HOMA-IR, and multivariable Cox proportional-hazards regression models to examine associations of the index with risk of prediabetes and T2D. During median 5.7, and 7.3 years of follow-up, we documented 928 prediabetes cases and 642 T2D cases. After adjusting for sociodemographic and lifestyle factors, a higher score on the plant-based dietary index was associated with lower insulin resistance (per 10 units higher score: β = −0.09; 95% CI: − 0.10; − 0.08), lower prediabetes risk (HR = 0.89; 95% CI: 0.81; 0.98), and lower T2D risk [HR = 0.82 (0.73; 0.92)]. After additional adjustment for BMI, associations attenuated and remained statistically significant for longitudinal insulin resistance [β = −0.05 (− 0.06; − 0.04)] and T2D risk [HR = 0.87 (0.79; 0.99)], but no longer for prediabetes risk [HR = 0.93 (0.85; 1.03)]. In conclusion, a more plant-based and less animal-based diet may lower risk of insulin resistance, prediabetes and T2D. These findings strengthen recent dietary recommendations to adopt a more plant-based diet.

Clinical Trial Registry number and website NTR6831, http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=6831.

Estudio del efecto fisiológico del consumo de arepas enriquecidas con pectina extraída de la cáscara de curuba (Passiflora tripartita var. mollissima)

Se evaluó el efecto fisiológico del consumo de arepas de maíz enriquecidas con 10% (p/p) de pectina extraída de cáscara de curuba sobre los niveles séricos de glucosa y lípidos en adultos voluntarios. La pectina se extrajo con ácido clorhídrico y se precipitó con etanol del 96% (v/v). En primer lugar, los voluntarios consumieron arepa sin pectina por siete días; después, arepa con 10% (p/p) de pectina cítrica comercial por 20 días y, finalmente, arepa con 10% de pectina de curuba por 20 días. Al mismo tiempo, se realizó un análisis sensorial de aceptación. Los resultados mostraron que, al consumir arepa con pectina de curuba, los niveles séricos de glucosa disminuyeron significativamente (5,88% (p = 0,023)), mientras que el perfil lipídico no se afectó. La arepa con pectina de curuba mostró mayor porcentaje de fibra dietética soluble, insoluble y total, así como menor porcentaje de carbohidratos disponibles, respecto a las otras arepas analizadas. El panel sensorial dictaminó baja aceptación en sabor y textura para las arepas con pectina cítrica comercial y con pectina de curuba. Se concluyó que la pectina de curuba puede aprovecharse para la formulación de arepas ya que ofrece a los consumidores un alimento benéfico para reducir los niveles de glucosa en la sangre.

Poor Dietary Guidelines Compliance among Low-Income Women Eligible for Supplemental Nutrition Assistance Program-Education (SNAP-Ed)

The Supplemental Nutrition Assistance Program-Education (SNAP-Ed) program aims to improve nutritional intakes of low-income individuals (<185% poverty threshold). The objective of this study was to describe the compliance with Dietary Guidelines for Americans (DGA) recommendations for fruits, vegetables, and whole grains among SNAP-Ed eligible (n = 3142) and ineligible (n = 3168) adult women (19–70 years) nationwide and SNAP-Ed participating women in Indiana (n = 2623), using the NHANES 2007–2012 and Indiana SNAP-Ed survey data, respectively. Sensitivity analysis further stratified women by race/ethnicity and by current SNAP participation (<130% poverty threshold). Nationally, lower-income women were less likely to meet the fruit (21% vs. 25%) and vegetable (11% vs. 19%) guidelines than higher-income women, but did not differ on whole grains, which were ~5% regardless of income. The income differences in fruit and vegetable intakes were driven by non-Hispanic whites. Fewer SNAP-Ed-eligible U.S. women met fruit (21% vs. 55%) and whole grain (4% vs. 18%) but did not differ for vegetable recommendations (11% vs. 9%) when compared to Indiana SNAP-Ed women. This same trend was observed among current SNAP participants. Different racial/ethnic group relationships with DGA compliance were found in Indiana compared to the nation. Nevertheless, most low-income women in the U.S. are at risk of not meeting DGA recommendations for fruits (79%), vegetables (89%), and whole grains (96%); SNAP-Ed participants in Indiana had higher compliance with DGA recommendations. Increased consumption of these three critical food groups would improve nutrient density, likely reduce calorie consumption by replacing high calorie choices, and improve fiber intakes.

Modeling insulin resistance in rodents by alterations in diet: what have high-fat and high-calorie diets revealed?

For over half a century, researchers have been feeding different diets to rodents to examine the effects of macronutrients on whole body and tissue insulin action. During this period, the number of different diets and the source of macronutrients employed have grown dramatically. Because of the large heterogeneity in both the source and percentage of different macronutrients used for studies, it is not surprising that different high-calorie diets do not produce the same changes in insulin action. Despite this, diverse high-calorie diets continue to be employed in an attempt to generate a "generic" insulin resistance. The high-fat diet in particular varies greatly between studies with regard to the source, complexity, and ratio of dietary fat, carbohydrate, and protein. This review examines the range of rodent dietary models and methods for assessing insulin action. In almost all studies reviewed, rodents fed diets that had more than 45% of dietary energy as fat or simple carbohydrates had reduced whole body insulin action compared with chow. However, different high-calorie diets produced significantly different effects in liver, muscle, and whole body insulin action when insulin action was measured by the hyperinsulinemic-euglycemic clamp method. Rodent dietary models remain an important tool for exploring potential mechanisms of insulin resistance, but more attention needs to be given to the total macronutrient content and composition when interpreting dietary effects on insulin action.

Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers

Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit.

Complementary Methodologies To Investigate Human Gut Microbiota in Host Health, Working towards Integrative Systems Biology

In 1680, Antonie van Leeuwenhoek noted compositional differences in his oral and fecal microbiota, pioneering the study of the diversity of the human microbiome. From Leeuwenhoek's time to successful modern attempts at changing the gut microbial landscape to cure disease, there has been an exponential increase in the recognition of our resident microbes as part of ourselves. Thus, the human host and microbiome have evolved in parallel to configure a balanced system in which microbes survive in homeostasis with our innate and acquired immune systems, unless disease occurs. A growing number of studies have demonstrated a correlation between the presence/absence of microbial taxa and some of their functional molecules (i.e., genes, proteins, and metabolites) with health and disease states. Nevertheless, misleading experimental design on human subjects and the cost and lack of standardized animal models pose challenges to answering the question of whether changes in microbiome composition are cause or consequence of a certain biological state. In this review, we evaluate the state of the art of methodologies that enable the study of the gut microbiome, encouraging a change in broadly used analytic strategies by choosing effector molecules (proteins and metabolites) in combination with coding nucleic acids. We further explore microbial and effector microbial product imbalances that relate to disease and health.

Impact of Dietary Fiber Consumption on Insulin Resistance and the Prevention of Type 2 Diabetes

Large prospective cohort studies consistently show associations of a high dietary fiber intake (>25 g/d in women and >38 g/d in men) with a 20-30% reduced risk of developing type 2 diabetes (T2D), after correction for confounders. It is less well recognized that these effects appear to be mainly driven by high intakes of whole grains and insoluble cereal fibers, which typically are nonviscous and do not relevantly influence postprandial glucose responses [i.e., glycemic index (GI)] or are strongly fermented by the gut microbiota in the colon. In contrast, a dietary focus on soluble, viscous, gel-forming, more readily fermentable fiber intakes derived from fruit and certain vegetables yields mixed results and generally does not appear to reduce T2D risk. Although disentangling types of fiber-rich foods and separating these from possible effects related to the GI is an obvious challenge, the common conclusion that key metabolic effects of high-fiber intake are explained by mechanisms that should mainly apply to the soluble, viscous type can be challenged. More recently, studies in humans and animal models focused on gaining mechanistic insights into why especially high-cereal-fiber (HCF) diets appear to improve insulin resistance (IR) and diabetes risk. Although effects of HCF diets on weight loss are only moderate and comparable to other types of dietary fibers, possible novel mechanisms have emerged, which include the prevention of the absorption of dietary protein and modulation of the amino acid metabolic signature. Here we provide an update of our previous review from 2008, with a focus on mechanistic insights of how HCF diets may improve IR and the risk of developing T2D.

Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: a systematic review and meta-analysis of randomized controlled trials

Background: There is strong epidemiologic evidence that dietary fiber intake is protective against overweight and obesity; however, results of intervention studies have been mixed. Soluble fiber beneficially affects metabolism, and fiber supplementation may be a feasible approach to improve body composition and glycemia in adults with overweight and obesity.Objective: We evaluated randomized controlled trials (RCTs) of isolated soluble fiber supplementation in overweight and obese adults on outcomes related to weight management [body mass index (BMI; in kg/m²), body weight, percentage of body fat, and waist circumference] and glucose and insulin metabolism (homeostasis model assessment of insulin resistance and fasting insulin) through a systematic review and meta-analysis.Design: We searched PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature and Cochrane Library databases. Eligible studies were RCTs that compared isolated soluble fiber with placebo treatments without energy-restriction protocols. Random-effects models were used to estimate pooled effect sizes and 95% CIs. Meta-regressions were performed to assess outcomes in relation to the intervention duration, fiber dose, and fiber type. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection.Results: Findings from 12 RCTs (n = 609 participants) from 2 to 17 wk of duration are summarized in this review. Soluble fiber supplementation reduced BMI by 0.84 (95% CI: -1.35, -0.32; P = 0.001), body weight by 2.52 kg (95% CI: -4.25, -0.79 kg; P = 0.004), body fat by 0.41% (95% CI: -0.58%, -0.24%; P < 0.001), fasting glucose by 0.17 mmol/L (95% CI: -0.28, -0.06 mmol/L; P = 0.002), and fasting insulin by 15.88 pmol/L (95% CI: -29.05, -2.71 pmol/L; P = 0.02) compared with the effects of placebo treatments. No publication bias was identified. Considerable between-study heterogeneity was observed for most outcomes.Conclusions: Isolated soluble fiber supplementation improves anthropometric and metabolic outcomes in overweight and obese adults, thereby indicating that supplementation may improve fiber intake and health in these individuals. However, the interpretation of these findings warrants caution because of the considerable between-study heterogeneity. This trial was registered at clinicaltrials.gov as NCT03003897.

Plasma glucose and insulin responses after consumption of breakfasts with different sources of soluble fiber in type 2 diabetes patients: a randomized crossover clinical trial

Background: The amount and quality of carbohydrates are important determinants of plasma glucose after meals. Regarding fiber content, it is unclear whether the intake of soluble fibers from foods or supplements has an equally beneficial effect on lowering postprandial glucose.Objective: The aim of our study was to compare the acute effect of soluble fiber intake from foods or supplements after a common meal on postprandial plasma glucose and plasma insulin in patients with type 2 diabetes (T2D).Design: A randomized crossover clinical trial was conducted in patients with T2D. Patients consumed isocaloric breakfasts (mean ± SD: 369.8 ± 9.4 kcal) with high amounts of fiber from diet food sources (total fiber: 9.7 g; soluble fiber: 5.4 g), high amounts of soluble fiber from guar gum supplement (total fiber: 9.1 g; soluble fiber: 5.4 g), and normal amounts of fiber (total fiber: 2.4 g; soluble fiber: 0.8 g). Primary outcomes were postprandial plasma glucose and insulin (0-180 min). Data were analyzed by repeated measures ANOVA and post hoc Bonferroni test.Results: A total of 19 patients [aged 65.8 ± 7.3 y; median (IQR), 10 (5-9) y of T2D duration; glycated hemoglobin 7.0% ± 0.8%; body mass index (in kg/m²) 28.2 ± 2.9] completed 57 meal tests. After breakfast, the incremental area under the curve (iAUC) for plasma glucose [mg/dL · min; mean (95% CI)] did not differ between high fiber from diet (HFD) [7861 (6257, 9465)] and high fiber from supplement (HFS) [7847 (5605, 10,090)] (P = 1.00) and both were lower than usual fiber (UF) [9527 (7549, 11,504)] (P = 0.014 and P = 0.037, respectively). iAUCs [μIU/mL · min; mean (95% CI)] did not differ (P = 0.877): HFD [3781 (2513, 5050)], HFS [4006 (2711, 5302), and UF [4315 (3027, 5603)].Conclusions: Higher fiber intake was associated with lower postprandial glucose at breakfast, and the intake of soluble fiber from food and supplement had a similar effect in patients with T2D. This trial was registered at clinicaltrials.gov as NCT02204384.

The Gastrointestinal Tract as an Integrator of Mechanical and Hormonal Response to Nutrient Ingestion

Glucose tolerance after meal ingestion in vivo is the result of multiple processes that occur in parallel. Insulin secretion together with reciprocal inhibition of glucagon secretion contributes to glucose tolerance. However, other factors beyond glucose effectiveness and insulin action require consideration. The absorption of ingested nutrients and their subsequent systemic rate of appearance largely depend on the rate of delivery of nutrients to the proximal small intestine. This is determined by the integrated response of the upper gastrointestinal tract to a meal. While gastric emptying is probably the most significant component, other factors need to be considered. This review will examine all processes that could potentially alter the fraction and rate of appearance of ingested nutrients in the peripheral circulation. Several of these processes may be potential therapeutic targets for the prevention and treatment of diabetes. Indeed, there is increased interest in gastrointestinal contributions to nutritional homeostasis, as demonstrated by the advent of antidiabetes therapies that alter gastrointestinal motility, the effect of bariatric surgery on diabetes remission, and the potential of the intestinal microbiome as a modulator of human metabolism. The overall goal of this review is to examine current knowledge of the gastrointestinal contributions to metabolic control.

Ethnopharmacological values of cassava and its potential for diabetes and dyslipidemia management: Knowledge survey and critical review of report

Background:

Beyond nutritional values are the pharmacological potentials of cassava comparative with other staple carbohydrate plant-based foods such as wheat. The knowledge of applicability to diabetes and its cardiovascular complications management seems not just limited but unacknowledged. As a preliminary study, a community’s knowledge of pharmacological value of cassava is investigated.

Methods:

Descriptive observational study using questionnaire-based “cross-sectional” survey was conducted. 136 Participants completed the survey and 101 respondents were selected for evaluation. Open-ended questions were used qualitatively to generate experience and view cassava values for diabetes and dyslipidemia. While categorical (yes or no) questions were used quantitatively to generate numerical results for diabetes, critical reanalysis of a report data was performed, especially comparing carbohydrate/fiber and fat/fiber ratios of cassava with wheat in view of dyslipidemia.

Result:

On the positive side, 42% of the participants believe that cassava has medicinal values. This includes 6% (among the 42) who believes that the plant is useful in treating diabetes and 24% who do not know it may be useful in diabetes management. Critical review showed that cassava may contribute up to sixteen times more fiber and four times less digestible sugar, as well as carbohydrate/fiber and fat/fiber ratios being 14 and 55 times less than wheat.

Conclusion:

There is evidence that relative to wheat flour meal, for instance, cassava contributes less fat and much more fiber. Since fat is pro-obesity, which in turn is pro-diabetic/metabolic syndrome; and fiber is anti-dyslipidemic; cassava has pharmacological values to be appreciated over some carbohydrate plant-based foods.

Changes in Gut Microbial Ecology and Immunological Responses of Mice Fed the Insoluble Fraction of Brassica rapa L. that was Fermented or Not

We aimed to investigate the effects of feeding fermented Brassica rapa L. on ecological and immunological changes in the mouse gut using in vitro cultivation tests and in vivo experiments in normal mice. In the preliminary in vitro study, two B. rapa L. products from different fermentation periods (one d [SF] or six months [LF]) were evaluated along with non-fermented vegetables (NF). Among the components of each product, the insoluble fraction resulted in the most prominent change such as a relative increase in butyrate production during a cultivation inoculated with mouse cecum contents. Based on this result, the boiled water-insoluble fractions of B. rapa L. (SF, LF, and NF samples) were selected as test materials for the subsequent in vivo experiment. Male C57BL/6J mice were divided into four groups and fed either a control diet (CON) or control diet plus one of the insoluble fractions for two weeks. The NF and LF groups had higher relative populations of Faecalibacterium prausnitzii than the CON group. Therefore, colonic butyrate concentrations were higher in the NF and LF groups than in the CON group. The oral administration of B. rapa L. extract induced immune regulatory effects, even when mice were fed NF and SF, but not LF, as assessed by an increase in regulatory T cell numbers. Our results indicate that feeding a purified insoluble fraction from B. rapa L. affects enteric short-chain fatty acid production and immunological responses in the mouse gut in a similar manner, regardless of the fermentation status.

A review of the characteristics of dietary fibers relevant to appetite and energy intake outcomes in human intervention trials

Background: Many intervention studies have tested the effect of dietary fibers (DFs) on appetite-related outcomes, with inconsistent results. However, DFs comprise a wide range of compounds with diverse properties, and the specific contribution of these to appetite control is not well characterized.Objective: The influence of specific DF characteristics [i.e., viscosity, gel-forming capacity, fermentability, or molecular weight (MW)] on appetite-related outcomes was assessed in healthy humans.Design: Controlled human intervention trials that tested the effects of well-characterized DFs on appetite ratings or energy intake were identified from a systematic search of literature. Studies were included only if they reported 1) DF name and origin and 2) data on viscosity, gelling properties, fermentability, or MW of the DF materials or DF-containing matrixes.Results: A high proportion of the potentially relevant literature was excluded because of lack of adequate DF characterization. In total, 49 articles that met these criteria were identified, which reported 90 comparisons of various DFs in foods, beverages, or supplements in acute or sustained-exposure trials. In 51 of the 90 comparisons, the DF-containing material of interest was efficacious for ≥1 appetite-related outcome. Reported differences in material viscosity, MW, or fermentability did not clearly correspond to differences in efficacy, whereas gel-forming DF sources were consistently efficacious (but with very few comparisons).Conclusions: The overall inconsistent relations of DF properties with respect to efficacy may reflect variation in measurement methodology, nature of the DF preparation and matrix, and study designs. Methods of DF characterization, incorporation, and study design are too inconsistent to allow generalized conclusions about the effects of DF properties on appetite and preclude the development of reliable, predictive, structure-function relations. Improved standards for characterization and reporting of DF sources and DF-containing materials are strongly recommended for future studies on the effects of DF on human physiology. This trial was registered at http://www.crd.york.ac.uk/PROSPERO as CRD42015015336.

Comparison of the Effects of Goat Dairy and Cow Dairy Based Breakfasts on Satiety, Appetite Hormones, and Metabolic Profile

The satiating effects of cow dairy have been thoroughly investigated; however, the effects of goat dairy on appetite have not been reported so far. Our study investigates the satiating effect of two breakfasts based on goat or cow dairy and their association with appetite related hormones and metabolic profile. Healthy adults consumed two breakfasts based on goat (G-Breakfast) or cow (C-Breakfast) dairy products. Blood samples were taken and VAS tests were performed at different time points. Blood metabolites were measured and Combined Satiety Index (CSI) and areas under the curves (AUC) were calculated. Desire to eat rating was significantly lower (breakfast &amp; time interaction p < 0.01) and hunger rating tended to be lower (breakfast &amp; time interaction p = 0.06) after the G-breakfast. None of the blood parameters studied were different between breakfasts; however, AUC_GLP-1 was inversely associated with the AUC_hunger and AUC_{desire-to-eat} after the G-Breakfast, whereas triglyceride levels were directly associated with AUC_CSI after the C-Breakfast. Our results suggest a slightly higher satiating effect of goat dairy when compared to cow dairy products, and pointed to a potential association of GLP-1 and triglyceride levels with the mechanisms by which dairy products might affect satiety after the G-Breakfast and C-Breakfast, respectively.

Polydextrose changes the gut microbiome and attenuates fasting triglyceride and cholesterol levels in Western diet fed mice

Obesity and dyslipidemia are hallmarks of metabolic and cardiovascular diseases. Polydextrose (PDX), a soluble fiber has lipid lowering effects. We hypothesize that PDX reduces triglycerides and cholesterol by influencing gut microbiota, which in turn modulate intestinal gene expression. C57BL/6 male mice were fed a Western diet (WD) ±75 mg PDX twice daily by oral gavage for 14 days. Body weight and food intake were monitored daily. Fasting plasma lipids, caecal microbiota and gene expression in intestine and liver were measured after 14 days of feeding. PDX supplementation to WD significantly reduced food intake (p < 0.001), fasting plasma triglyceride (p < 0.001) and total cholesterol (p < 0.05). Microbiome analysis revealed that the relative abundance of Allobaculum, Bifidobacterium and Coriobacteriaceae taxa associated with lean phenotype, increased in WD + PDX mice. Gene expression analysis with linear mixed-effects model showed consistent downregulation of Dgat1, Cd36, Fiaf and upregulation of Fxr in duodenum, jejunum, ileum and colon in WD + PDX mice. Spearman correlations indicated that genera enriched in WD + PDX mice inversely correlated with fasting lipids and downregulated genes Dgat1, Cd36 and Fiaf while positively with upregulated gene Fxr. These results suggest that PDX in mice fed WD promoted systemic changes via regulation of the gut microbiota and gene expression in intestinal tract.

Exploring the human microbiome from multiple perspectives: factors altering its composition and function

Our microbiota presents peculiarities and characteristics that may be altered by multiple factors. The degree and consequences of these alterations depend on the nature, strength and duration of the perturbations as well as the structure and stability of each microbiota. The aim of this review is to sketch a very broad picture of the factors commonly influencing different body sites, and which have been associated with alterations in the human microbiota in terms of composition and function. To do so, first, a graphical representation of bacterial, fungal and archaeal genera reveals possible associations among genera affected by different factors. Then, the revision of sequence-based predictions provides associations with functions that become part of the active metabolism. Finally, examination of microbial metabolite contents and fluxes reveals whether metabolic alterations are a reflection of the differences observed at the level of population structure, and in the last step, link microorganisms to functions under perturbations that differ in nature and aetiology. The utilisation of complementary technologies and methods, with a special focus on metabolomics research, is thoroughly discussed to obtain a global picture of microbiota composition and microbiome function and to convey the urgent need for the standardisation of protocols.

The impact of diet-based glycaemic response and glucose regulation on cognition: evidence across the lifespan

The brain has a high metabolic rate and its metabolism is almost entirely restricted to oxidative utilisation of glucose. These factors emphasise the extreme dependence of neural tissue on a stable and adequate supply of glucose. Whereas initially it was thought that only glucose deprivation (i.e. under hypoglycaemic conditions) can affect brain function, it has become apparent that low-level fluctuations in central availability can affect neural and consequently, cognitive performance. In the present paper the impact of diet-based glycaemic response and glucose regulation on cognitive processes across the lifespan will be reviewed. The data suggest that although an acute rise in blood glucose levels has some short-term improvements of cognitive function, a more stable blood glucose profile, which avoids greater peaks and troughs in circulating glucose is associated with better cognitive function and a lower risk of cognitive impairments in the longer term. Therefore, a habitual diet that secures optimal glucose delivery to the brain in the fed and fasting states should be most advantageous for the maintenance of cognitive function. Although the evidence to date is promising, it is insufficient to allow firm and evidence-based nutritional recommendations. The rise in obesity, diabetes and metabolic syndrome in recent years highlights the need for targeted dietary and lifestyle strategies to promote healthy lifestyle and brain function across the lifespan and for future generations. Consequently, there is an urgent need for hypothesis-driven, randomised controlled trials that evaluate the role of different glycaemic manipulations on cognition.

Re-evaluation of guar gum (E 412) as a food additive

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re‐evaluating the safety of guar gum (E 412) as a food additive. In the EU, guar gum was evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1970, 1974 and 1975, who allocated an acceptable daily intake (ADI) ‘not specified’. Guar gum has been also evaluated by the Scientific Committee for Food (SCF) in 1977 who endorsed the ADI ‘not specified’ allocated by JECFA. Following the conceptual framework for the risk assessment of certain food additives re‐evaluated under Commission Regulation (EU) No 257/2010, the Panel considered that adequate exposure and toxicity data were available. Guar gum is practically undigested, not absorbed intact, but significantly fermented by enteric bacteria in humans. No adverse effects were reported in subchronic and carcinogenicity studies at the highest dose tested; no concern with respect to the genotoxicity. Oral intake of guar gum was well tolerated in adults. The Panel concluded that there is no need for a numerical ADI for guar gum (E 412), and there is no safety concern for the general population at the refined exposure assessment of guar gum (E 412) as a food additive. The Panel considered that for uses of guar gum in foods intended for infants and young children the occurrence of abdominal discomfort should be monitored and if this effect is observed doses should be identified as a basis for further risk assessment. The Panel considered that no adequate specific studies addressing the safety of use of guar gum (E 412) in food categories 13.1.5.1 and 13.1.5.2 were available. Therefore, the Panel concluded that the available data do not allow an adequate assessment of the safety of guar gum (E 412) in infants and young children consuming these foods for special medical purposes.

Comparison of Segmental Colon Transit Time With Total Energy Expenditure in Psychiatry Unit Patients

Physical activity is associated with a reduced risk of colorectal cancer. We examined the colon transit time (CTT) according to the total energy expenditure (TEE) in psychiatry unit patients. The study participants included 67 adults, with a mean age of 49.8 years. The participants used an accelerometer for 7 days to measure their 1-week TEE. They took a capsule containing 20 radio-opaque markers for 3 days. On the 4th day and 7th day, a supine abdominal radiography was performed. According to the TEE of all study participants, the upper 30%, middle 30%, and lower 40% were classified into groups according to high (H), moderate (M), and low (L) physical activity. The mean total CTT was 52.0 hours. The segmental CTT for the right, left, and recto-sigmoid colon were 15.3 hours, 19.2 hours, and 17.4 hours. Total CTT in the H group was significantly shorter than that in the L group (p = .010). A comparison of the segmental CTT between the L, M, and H groups showed that the right CTT (p = .010) of the H group was significantly shorter than that of the M group. The left CTT of the M group (p = .028) and H group (p = .004) was significantly shorter than that of the L group. The recto-sigmoid CTT (p = .016) of the M group was significantly shorter than that of the L group. The study showed that moderate and high TEE was assisted with reduced CTT.

The Obesity-Impulsivity Axis: Potential Metabolic Interventions in Chronic Psychiatric Patients

Pathological impulsivity is encountered in a broad range of psychiatric conditions and is thought to be a risk factor for aggression directed against oneself or others. Recently, a strong association was found between impulsivity and obesity which may explain the high prevalence of metabolic disorders in individuals with mental illness even in the absence of exposure to psychotropic drugs. As the overlapping neurobiology of impulsivity and obesity is being unraveled, the question asked louder and louder is whether they should be treated concomitantly. The treatment of obesity and metabolic dysregulations in chronic psychiatric patients is currently underutilized and often initiated late, making correction more difficult to achieve. Addressing obesity and metabolic dysfunction in a preventive manner may not only lower morbidity and mortality but also the excessive impulsivity, decreasing the risk for aggression. In this review, we take a look beyond psychopharmacological interventions and discuss dietary and physical therapy approaches.

Effects of dietary fiber on the antioxidant capacity, immune status, and antioxidant-relative signaling molecular gene expression in rat organs

This study was conducted to evaluate the effects of different fibers, such as dietary pea, sweet potato, and wheat bran fibers, on the antioxidant capacity, immune status, and antioxidant-related signaling molecules of rat organs.

The difference between oats and beta-glucan extract intake in the management of HbA1c, fasting glucose and insulin sensitivity: a meta-analysis of randomized controlled trials

Increasing oats and beta-glucan extract intake has been associated with improved glycemic control, which is associated with the reduction in the development of diabetes. This study aims to assess the different effects between oat (whole and bran) and beta-glucan extract intake on glycemic control and insulin sensitivity. PubMed, Embase, Medline, The Cochrane Library, CINAHL and Web of Science were searched up to February 2014. We included randomized controlled trials with interventions that lasted at least four weeks that compared oats and beta-glucan (extracted from oats or other sources) intake with a control. A total of 1351 articles were screened for eligibility, and relevant data were extracted from 18 studies (n = 1024). Oat product dose ranged from 20 g d(-1) to 136 g d(-1), and beta-glucan extract dose ranged from 3 g d(-1) to 10 g d(-1). Compared with the control, oat intake resulted in a greater decrease in fasting glucose and insulin of subjects (P < 0.05), but beta-glucan extract intake did not. Furthermore, oat intake resulted in a greater decrease in glycosylated hemoglobin (HbA1c) (P < 0.001, I(2) = 0%) and fasting glucose (P < 0.001, I(2) = 68%) after removing one study using a concentrate and a different design and fasting insulin of type 2 diabetes (T2D) (P < 0.001, I(2) = 0%). The intake of oats and beta-glucan extracted from oats were effective in decreasing fasting glucose (P = 0.007, I(2) = 91%) and fasting insulin of T2D (P < 0.001, I(2) = 0%) and tented to lower HbA1c (P = 0.09, I(2) = 92%). Higher consumption of whole oats and oat bran, but not oat or barley beta-glucan extracts, are associated with lower HbA1c, fasting glucose and fasting insulin of T2D, hyperlipidaemic and overweight subjects, especially people with T2D, which supports the need for clinical trials to evaluate the potential role of oats in approaching to the management of glycemic control and insulin sensitivity of diabetes or metabolic syndrome subjects.

Nutrition Interventions for Chronic Liver Diseases and Nonalcoholic Fatty Liver Disease

The progressively increasing rates of obesity have led to a worldwide epidemic of nonalcoholic fatty liver disease (NAFLD), the hepatic manifestation of the metabolic syndrome. It is currently the most common cause of liver disease worldwide and projected to be the leading indication for liver transplantation in the United States by 2020. NAFLD is associated with both liver-related and overall mortality. Undoubtedly, nutrition interventions are key in the treatment of NAFLD, to reverse the disease, and prevent disease progression, complications, and associated comorbidities, including cardiovascular disease and diabetes.

Natural Dietary and Herbal Products in Anti-Obesity Treatment

The prevalence of overweight and obesity is on the rise around the world. Common comorbidities associated with obesity, particularly diabetes, hypertension, and heart disease have an impact on social and financial systems. Appropriate lifestyle and behavior interventions are still the crucial cornerstone to weight loss success, but maintaining such a healthy lifestyle is extremely challenging. Abundant natural materials have been explored for their obesity treatment potential and widely used to promote the development of anti-obesity products. The weight loss segment is one of the major contributors to the overall revenue of the dietary supplements market. In this review, the anti-obesity effects of different dietary or herbal products, and their active ingredients and mechanisms of action against obesity will be discussed.

Bamboo shoot fiber prevents obesity in mice by modulating the gut microbiota

Dietary fiber has been shown to prevent high-fat diet induced obesity through modulating the gut microbiota; however, quality difference in fiber type is largely unknown. We performed a 6 week study on C57BL/6J mice fed a macronutrient matched high-fat diet with different fiber types including cellulose (HFC), bamboo shoot fiber (HFBS) and several other commonly consumed fibers. Our results showed that the HFBS group exhibited the lowest weight gain among all diet groups and had improved lipid profiles and glycemic control compared with the HFC group. As revealed by 16S rRNA gene sequencing, loss of diversity in the gut microbiota induced by the HFC diet was largely prevented by the HFBS diet. Moreover, compared with the HFC diet, the HFBS diet resulted in markedly increased relative abundance of Bacteroidetes and strong inhibition of Verrucomicrobia, two divisions strongly correlated with body weight. In conclusion, the present study provides evidence of a quality difference among different types of dietary fibers and shows that bamboo shoot fiber is the most effective in suppressing high-fat diet induced obesity. Our findings indicate that bamboo shoot fiber is a potential prebiotic fiber which modulates the gut microbiota and improves host metabolism.

Usual Intake of Added Sugars and Saturated Fats Is High while Dietary Fiber Is Low in the Mexican Population

BACKGROUND

The Mexican National Health and Nutrition Survey (ENSANUT) was carried out in 2012. Information from the survey is used to design and evaluate food and nutrition policies in Mexico.

OBJECTIVE

The objective of this study was to estimate the usual intake of energy and macronutrients in the Mexican population by using the ENSANUT 2012.

METHODS

Twenty-four-hour recall interviews were administered to a nationally representative subsample of 10,096 individuals aged ≥1 y from the ENSANUT 2012. Usual intake distributions and the prevalence of inadequate intakes were estimated by using the Iowa State University method. Student's t tests and tests on the equality of proportions were used to compare usual intakes and prevalence of inadequacy across socioeconomic status, area (rural or urban), and region of residence (North, Center, or South).

RESULTS

Energy and macronutrient intakes and indicators of dietary adequacy are presented for children (ages 1-4 y and 5-11 y), adolescents (12-19 y), and adults (≥20 y). At the national level, the estimated mean fiber intake was below the Adequate Intake for all population subgroups, suggesting inadequacies. The estimated proportion with a usual added sugars intake of >10% of total energy intake was >64% in all age groups. The proportion with a usual saturated fat intake of >10% of total energy intake was estimated to be >78% in children, >66% in adolescents, and >50% in adults. Overall, fiber intake was lower and intakes of saturated fat and added sugars were higher in urban compared with rural areas, in the North compared with South regions, and among those with high compared with low socioeconomic status (P < 0.05).

CONCLUSIONS

Fiber intake is lower and added sugar and saturated fat intakes are higher than recommended for >50% of the Mexican population aged ≥1 y. These results highlight the importance of improving the diets of the overall population to reduce the risk of noncommunicable chronic diseases.

Polyphenol-rich strawberry extract (PRSE) shows in vitro and in vivo biological activity against invasive breast cancer cells

We describe the biological effects of a polyphenol-rich strawberry extract (PRSE), obtained from the “Alba” variety, on the highly aggressive and invasive basal-like breast cancer cell line A17. Dose-response and time-course experiments showed that PRSE is able to decrease the cellular viability of A17 cells in a time- and dose-dependent manner. PRSE effect on cell survival was investigated in other tumor and normal cell lines of both mouse and human origin, demonstrating that PRSE is more active against breast cancer cells. Cytofluorimetric analysis of A17 cells demonstrated that sub-lethal doses of PRSE reduce the number of cells in S phase, inducing the accumulation of cells in G1 phase of cell cycle. In addition, the migration of A17 cells was studied monitoring the ability of PRSE to inhibit cellular mobility. Gene expression analysis revealed the modulation of 12 genes playing different roles in the cellular migration, adhesion and invasion processes. Finally, in vivo experiments showed the growth inhibition of A17 cells orthotopically transplanted into FVB syngeneic mice fed with PRSE. Overall, we demonstrated that PRSE exerts important biological activities against a highly invasive breast cancer cell line both in vitro and in vivo suggesting the strawberry extracts as preventive/curative food strategy.

Konjac glucomannan, a promising polysaccharide of Amorphophallus konjac K. Koch in health care

In recent year, konjac glucomannan (KGM) has attracted more attention due to its non-harmful and non-toxic properties, good biocompatibility, biodegradability and hydrophilic ability. Moreover, KGM and their derivatives have several importances in the multidirectional research areas such as nutritional, biotechnological and fine chemical fields. In the previous article, we have reviewed the nutritional aspects of KGM covering the various aspects of functional foods, food additives and their derivatives. This review aims at highlighting the diverse biomedical research conducted on KGM in the past ten years, covering therapies for anti-obesity, regulation in lipid metabolism, laxative effect, anti-diabetic, anti-inflammatory, prebiotic to wound dressing applications. Moreover, this review deals with global health aspects of KGM and the disparate health related factors associated with diseases and their control measures.

Effects of Dietary Fibre (Pectin) and/or Increased Protein (Casein or Pea) on Satiety, Body Weight, Adiposity and Caecal Fermentation in High Fat Diet-Induced Obese Rats

Dietary constituents that suppress appetite, such as dietary fibre and protein, may aid weight loss in obesity. The soluble fermentable dietary fibre pectin promotes satiety and decreases adiposity in diet-induced obese rats but effects of increased protein are unknown. Adult diet-induced obese rats reared on high fat diet (45% energy from fat) were given experimental diets ad libitum for 4 weeks (n = 8/group): high fat control, high fat with high protein (40% energy) as casein or pea protein, or these diets with added 10% w/w pectin. Dietary pectin, but not high protein, decreased food intake by 23% and induced 23% body fat loss, leading to 12% lower final body weight and 44% lower total body fat mass than controls. Plasma concentrations of satiety hormones PYY and total GLP-1 were increased by dietary pectin (168% and 151%, respectively) but not by high protein. Plasma leptin was decreased by 62% on pectin diets and 38% on high pea (but not casein) protein, while plasma insulin was decreased by 44% on pectin, 38% on high pea and 18% on high casein protein diets. Caecal weight and short-chain fatty acid concentrations in the caecum were increased in pectin-fed and high pea protein groups: caecal succinate was increased by pectin (900%), acetate and propionate by pectin (123% and 118%, respectively) and pea protein (147% and 144%, respectively), and butyrate only by pea protein (309%). Caecal branched-chain fatty acid concentrations were decreased by pectin (down 78%) but increased by pea protein (164%). Therefore, the soluble fermentable fibre pectin appeared more effective than high protein for increasing satiety and decreasing caloric intake and adiposity while on high fat diet, and produced a fermentation environment more likely to promote hindgut health. Altogether these data indicate that high fibre may be better than high protein for weight (fat) loss in obesity.

Long-term antihypertensive effect of a soluble cocoa fiber product in spontaneously hypertensive rats

Background and Methods

This study evaluates the antihypertensive effect of long-term intake of a soluble cocoa fiber product (SCFP). Different doses of SCFP were evaluated (200, 400, and 800 mg/kg/day) and a dose of 800 mg/kg/day of beta-glucan 0.75 (BETA-G) was used as a standard fiber. Water, a neutral vehicle, was used as negative control, and 50 mg/kg/day captopril was used as positive control. Systolic blood pressure (SBP) was measured weekly by the tail cuff method. Body weight, food, and liquid intake were also registered weekly in the rats from 10 to 24 weeks of life. Glucose, total cholesterol, and triglyceride levels; redox status; and the angiotensin-converting enzyme activity were also studied in the plasma samples of these animals.

Results

Throughout the 10 weeks of treatment, captopril and SCFP (400 mg/kg/day) demonstrated blood pressure lowering effects in the spontaneously hypertensive rats (p<0.05; n=8). Paradoxically, neither the highest dose (800 mg/kg/day) of SCFP decreased SBP nor 800 mg/kg/day BETA-G (p>0.05; n=8). When the corresponding antihypertensive treatment, was disrupted the SBP values of the 400 mg/kg/day SCFP treated animals returned to control values (p>0.05; n=8). In addition, the SCFP significantly decreased (p<0.05; n=4) the glucose, cholesterol, and triglyceride levels and also the liver and plasma malondaldehyde levels. Moreover, the SCFP slightly increased the reduced glutathione levels in the liver.

Conclusion

The SCFP could be used to control the blood pressure of hypertensive subjects for a long period of time and could improve metabolic complications associated to cardiovascular diseases.

Therapeutic effects of soluble dietary fiber consumption on type 2 diabetes mellitus

Soluble dietary fiber (DF) reduces the risk of developing diabetes and may have therapeutic effects in patients with type 2 diabetes mellitus (DM2). The present study aimed to investigate the effect of soluble DF on metabolic control in patients with DM2. A total of 117 patients with DM2 between the ages of 40 and 70 were assessed. Patients were randomly assigned to one of two groups, and administered extra soluble DF (10 or 20 g/day), or to a control group (0 g/day) for one month. Blood glucose, serum insulin and connecting peptide (C-peptide) levels, and the insulin resistance index, as determined using the homeostatic model assessment method, were measured during fasting and up to 2-h postprandially prior to and following one month of treatment. Other measurements included serum levels of glycated albumin (GA), blood lipid profiles, and an analysis of the blood pressure, body weight and waist/hip ratio of all patients. Following intervention, the levels of 2-h blood glucose, fasting insulin and lipoprotein(a), and the insulin resistance index, were significantly improved in all groups. Furthermore, the fasting blood glucose, 2-h insulin, fasting C-peptide, 2-h C-peptide, GA and triglyceride (TG) levels were significantly improved in the soluble DF groups. The 20 g/day soluble DF group exhibited significantly improved fasting blood glucose and low-density lipoprotein levels, as well as a significantly improved insulin resistance index. In addition, 10 and 20 g/day soluble DF significantly improved the waist and hip circumferences and levels of TGs and apolipoprotein A. The results of the present study suggested that increased and regular consumption of soluble DF led to significant improvements in blood glucose levels, insulin resistance and metabolic profiles, without improving the secretory function of the islets of Langerhans, over a short-term intervention period in patients with DM2.

Intake of whole grains is associated with lower risk of myocardial infarction: the Danish Diet, Cancer and Health Cohort

BACKGROUND

High intake of whole grains has been associated with lower risk of coronary heart disease; however, the research that has been used to evaluate different effects of different whole-grain cereals (e.g., wheat, rye, and oats) has been sparse.

OBJECTIVE

We investigated the association between whole-grain intake in terms of total intake and intakes of different cereals and myocardial infarction.

DESIGN

This prospective study included 54,871 Danish adults aged 50-64 y, of whom 2329 individuals developed myocardial infarction (13.6 y of follow-up). Detailed information on daily intake of whole-grain products was available from a self-administered food-frequency questionnaire, and intakes of total whole grain and whole-grain species (wheat, rye, and oats) were estimated. The association between intake of whole grains and risk of myocardial infarction was examined with the use of a Cox proportional hazards model adjusted for potential confounders.

RESULTS

For both men and women with total whole-grain intake in the highest quartile, lower risks of myocardial infarction were shown [HRs: 0.75 (95% CI: 0.65, 0.86) and 0.73 (95% CI: 0.58, 0.91), respectively] than for individuals with intake in the lowest quartile. When the specific cereal species were considered, rye and oats, but not wheat, were associated with lower myocardial infarction risk in men. No significant associations were seen in women. For total whole-grain products, significantly lower myocardial infarction risks were seen with higher intakes in both men and women. Rye bread (in men and women) and oatmeal (in men) were associated with significantly lower risk of myocardial infarction, whereas no significant association was shown for whole-grain bread, crispbread, and wheat.

CONCLUSION

In this study, we provide support for the hypothesis that whole-grain intake is related to lower risk of myocardial infarction and suggest that the cereals rye and oats might especially hold a beneficial effect.

Mechanism of Butyrate Stimulation of Triglyceride Storage and Adipokine Expression during Adipogenic Differentiation of Porcine Stromovascular Cells

Short chain fatty acids (SCFA), products of microbial fermentation of dietary fiber, exert multiple metabolic effects in cells. Previously, we had demonstrated that soluble fiber influenced fat mass accumulation, gut microbial community structure and SCFA production in pigs. The current study was designed to identify effects of SCFA treatment during adipogenic differentiation of porcine stromovascular cells on lipid metabolism and adipokine expression. Differentiating cells were treated with varying concentrations of butyrate. Results show that butyrate treatment enhanced adipogenesis and lipid accumulation, perhaps through upregulation of glucose uptake and de novo lipogenesis and other mechanisms that include induction of SREBP-1c, C/EBPα/β, GLUT4, LPL, PPARγ, GPAT4, DGAT1 and DGAT2 expression. In addition, butyrate induced adiponectin expression, resulting in activation of downstream target genes, such as AMPK and AKT. Activation of AMPK by butyrate led to phosphorylation of ACC. Although increased ACO gene expression was seen with butyrate treatment, experiments with the peroxisomal fatty acid inhibitor, thioridazine, suggest that butyrate may have an inhibitory effect on peroxisomal fatty acid oxidation. Our studies also provide evidence that butyrate may inhibit lipolysis, perhaps in an FFAR3-dependent manner. Therefore, this study presents a novel paradigm for butyrate action in adipocytes and shows that adipocytes are capable of utilizing butyrate, leading to increased expression of adiponectin for enhanced glucose uptake and improved insulin sensitivity.

Dietary fibre intake and mortality from cardiovascular disease and all cancers: A meta-analysis of prospective cohort studies

BACKGROUND

Accumulating evidence supports health benefits of dietary fibre, such as improving lipid profiles, lowering blood pressure and improving insulin sensitivity, but evidence from comprehensive investigation of dietary fibre intake and mortality from cardiovascular disease (CVD) and all cancers is limited.

AIMS

To quantitatively assess the association between dietary fibre intake and mortality from CVD and all cancers.

METHODS

We performed a meta-analysis of prospective cohort studies. Eligible studies were identified by searching PubMed and Embase databases for all articles published up to September 2014 and via hand searching. Study-specific estimates adjusting for potential confounders were combined to calculate pooled relative risks (RRs) with 95% confidence intervals (CIs), using a random-effects model.

RESULTS

We found 15 studies that examined the association between dietary fibre and mortality from CVD, coronary heart disease (CHD) and all cancers. The pooled RRs of CVD, CHD and all-cancer mortality for the highest versus lowest category of dietary fibre were 0.77 (95% CI: 0.71-0.84), 0.76 (95% CI: 0.67-0.87) and 0.86 (95% CI: 0.79-0.93), respectively. In a dose-response meta-analysis, the pooled RRs for an increment of 10 g/day in dietary fibre intake were 0.91 (95% CI: 0.88-0.94) for CVD, 0.89 (95% CI: 0.85-0.93) for CHD and 0.94 (95% CI: 0.91-0.97) for all cancers.

CONCLUSIONS

Our findings suggest that high dietary fibre intake is associated with a reduced risk of mortality from CVD and all cancers. These results support the current recommendation that high dietary fibre intake should be part of a healthy diet.