Insoluble Dietary Fiber Intake Research Articles

Types of fiber and gut microbiota composition and diversity among arab females

ObjectivesDietary fiber is recognizedas an important nutrient for gut health. However, research on the relations of different types of fibers (soluble and insoluble) to the human microbiota health is limited. This study aimed to identify whether higher habitual intake of soluble and/or insoluble fiber have a different influence on the composition, diversity, and abundance of microbiota. MethodsWe examined the fecal microbial composition of 92 healthy females aged 18 and above using the novel shotgun metagenomics sequencing technique. The habitual fiber intake was determined using the Saudi food frequency questionnaire. Pearson’s correlation was used for the correlations between total, soluble, and insoluble fiber and gut microbiota. α- and β-diversities were applied to acquire the distinctions in the relative abundances of bacterial taxa. ResultsOur findings show that higher dietary fiber, particularly insoluble fiber, was significantly correlated with the abundances of Bacteroides_u_s, Bacteroides uniformis, and Lactobacillus acidophilus (r = 0.26, 0.29, 0.26, p-value < 0.05, respectively). Non-significant difference was noted in the microbial α-diversity and β-diversity in low and high soluble/insoluble dietary fiber. ConclusionsCurrent findings suggest that insoluble dietary-fiber intake is favorably correlated with the health of the human gut microbiota. However, further investigations are necessary to identify the effect of types of fiber on the specific species identified in this study.

Development and Validation of a Mobile Phone Application Developed for Measuring Dietary Fiber Intake.

We have developed a mobile phone application for measuring the intake of dietary fiber and validated the ability of the application to accurately capture this intake against measurements registered by a dietary record. We also investigated what food groups contributed most to the total, soluble, and insoluble dietary fiber intake. Twenty-six randomly selected Swedish women aged 35–85 years were included and randomized to either start to register dietary intake in the application or by a dietary record, during three consecutive days. After a washout period of at least two weeks, the participants used the other method. We found that the difference in measured mean fiber intake between the dietary record and the application was two grams independent of the total intake per day. A statistically significant correlation between fiber intake as measured by the two methods was found (rho = 0.65, p < 0.001). Vegetables and roots were the predominantly contributing foods to total and soluble fiber intake. Bread and crackers contributed most to insoluble fiber intake. In conclusion, the application may be considered as a useful and easy-to-use method to measure dietary fiber intake.

Insoluble dietary fibre intake is associated with lower prevalence of newly-diagnosed non-alcoholic fatty liver disease in Chinese men: a large population-based cross-sectional study

BackgroundThe health benefits of dietary fibre (DF) intake on non-alcoholic fatty liver disease (NAFLD) are controversial. Thus, this large cross-sectional study aimed to determine the associations between DF intake and the prevalence of newly-diagnosed NAFLD in a large general population.MethodsA total of 23,529 participants were enrolled in the analyses. Newly-diagnosed NAFLD was diagnosed according to liver ultrasonography and history of alcohol intake. DF intake was assessed using a validated self-administered food frequency questionnaire. Logistic regression analysis was applied to estimate the associations between DF intake and NAFLD.ResultsIn total, 18.81% (n = 4426) of the participants were newly diagnosed with NAFLD. Compared with the participants in the lowest quartile of DF intake, the ORs (95% CI) for the participants in the highest quartile were 0.81 (0.67, 0.97), 0.78 (0.62, 0.99), and 0.85 (0.62, 1.17) for all participants, men, and women, respectively. Compared with the participants in the lowest quartile of insoluble DF intake, the ORs (95% CI) for the participants in the highest quartile were 0.70 (0.58, 0.85), 0.60 (0.47, 0.76), and 0.95 (0.68, 1.32) in all participants, men, and women, respectively. No association was observed between soluble DF intake and NAFLD. DF from whole grain, soy foods, vegetables, and nuts but not fruits were negatively associated with NAFLD.ConclusionsA higher intake of insoluble DF is associated with lower prevalence of newly-diagnosed NAFLD in men. Moreover, intake DF from whole grain, soy foods, vegetables, and nuts, but not fruits have favorable effect on the prevalence of newly diagnosed NAFLD. Further cohort studies and randomized controlled trials are needed to validate this finding.

Anti-diabetic effects of soluble and insoluble dietary fibre from deoiled cumin in low-dose streptozotocin and high glucose-fat diet-induced type 2 diabetic rats

The effects of soluble dietary fibre (SDF) and insoluble dietary fibre (IDF) from deoiled cumin on low-dose streptozotocin and high glucose-fat-induced type 2 diabetes rats were examined. Male Wistar rats were divided into nine groups: control (non-diabetic, no SDF or IDF intake), model (diabetes only), metformin, high-dose SDF (5 g/kg body weight), middle-dose SDF (500 mg/kg body weight), low-dose SDF (250 mg/kg body weight), high-dose IDF (5 g/kg body weight), middle-dose IDF (500 mg/kg body weight), and low-dose IDF (250 mg/kg body weight). SDF treatments, in particular, middle-dose SDF for 4 weeks, induced better regulation of blood glucose, insulin, hormones, and liver lipid metabolism in diabetic rats, accompanied by increased levels of short-chain fatty acids in colon and decreased fatty degeneration of liver. Our results collectively support the therapeutic potential of SDF from deoiled cumin in type 2 diabetes.

Soluble and insoluble dietary fibre intake and risk factors for metabolic syndrome and cardiovascular disease in middle-aged adults: the AWHS cohort.

The Westernization of the Mediterranean lifestyle has led to a modification of certain dietary habits such as a decrease in the consumption of dietary fibre-rich foods. The impact of these changes on cardiovascular diseases (CVD) has been studied over the last few years and the effect of the different sources of fibre on cardiovascular risk parameters and coronary heart disease (CHD) continues to create controversy. To evaluate the association between the source of dietary fibre and the prevalence of metabolic syndrome (MetS) and other cardiovascular risk factors in a Spanish working population. The study was carried out in a sample of 1592 Spanish workers free of CVD (40-55 years old) within the Aragon Workers' Health Study (AWHS) cohort. Sociodemographic, anthropometric, clinical and biochemical data were collected. Fibre intake was assessed by means of a validated 136-items semiquantitative food-frequency questionnaire. MetS was defined by using the modified National Cholesterol Education Programme - Adult Treatment Panel III (NCEP- ATP III) definition. After adjusting for possible confounding factors, we found an inverse association between insoluble fibre intake and systolic and diastolic blood pressure, total cholesterol, triglycerides, apolipoprotein B100 and ratio TG/HDL. Soluble fibre was inversely associated with triglycerides and apolipoprotein B100. Furthermore, prevalence of MetS was found to be lower (OR 0.62, 95% CI: 0.40-0.96) in those participants in the highest quartile of insoluble fibre intake. A higher intake of insoluble fibre could play an important role in the control and management of hypertension, lipid profile and MetS.

Soluble and insoluble dietary fibre intake and risk factors for cvd and metabolic syndrome in middle-aged adults: The AWHS cohort

Soluble and insoluble dietary fibre intake and risk factors for cvd and metabolic syndrome in middle-aged adults: The AWHS cohort

Heterogeneous associations of insoluble dietary fibre intake with subsequent glycosylated Hb levels among Chinese adults with type 2 diabetes: a quantile regression approach.

Dietary fibre intake has been suggested to reduce blood glucose levels in diabetic patients, particularly when glycosylated Hb (HbA1c) levels are high. In the present study, we used a quantile regression (QR) approach to characterise the possible heterogeneous associations of dietary fibre intake with HbA1c levels in Chinese diabetic patients. A total of 497 diabetic patients participated in the baseline survey in 2006 and in the follow-up survey in 2011, both of which were conducted in Pudong New Area of Shanghai, China. Structured in-person interviews were conducted to collect information on demographic characteristics and lifestyle factors. Dietary intake was assessed using a validated FFQ. Blood samples were collected during the interviews for biochemical assays. QR models were used to examine the heterogeneous associations of dietary factors with HbA1c levels. A significant marginal association of insoluble dietary fibre intake with subsequent HbA1c levels was observed only when the HbA1c level was over 6·8%. The associations appeared to be greater when the quantile levels of HbA1c were higher. The coefficient estimates were -0·174 (95% CI -0·433, -0·025) at the quantile of 0·60, -0·200 (95% CI -0·306, -0·008) at 0·70, -0·221 (95% CI -0·426, -0·117) at 0·80, and -0·389 (95% CI -0·516, -0·018) at 0·90. A similar pattern was observed for the associations of dietary glycaemic index (GI) value with HbA1c levels. In conclusion, the present results indicate that the associations of insoluble dietary fibre intake and GI value with subsequent HbA1c levels depend on glycaemic control status in Chinese diabetic patients. More studies are required to confirm our findings.

Evaluación del consumo de fibra alimentaria en pacientes con diabetes tipo 2 que concurren a un centro asistencial de la ciudad de Rosario

Introducción: una dieta rica en fibra se ha asociado con el mejor control glicémico en pacientes con diabetes 2, siendo la fracción soluble la más eficaz en el control de la glicemia. El presente estudio tiene el propósito de determinar la cantidad de fibra dietética total, soluble e insoluble consumida por los pacientes con diabetes tipo 2 que concurrieron a un centro asistencial para diabéticos de la ciudad de Rosario.Material y métodos: se realizó un estudio de tipo descriptivo, observacional, de corte transversal. Se determinó una muestra de 60 adultos, con diagnóstico de diabetes tipo 2 (&gt;6 meses), de 18 a 70 años, sin enfermedades o afecciones intestinales. Se empleó un cuestionario de frecuencia de consumo semicuantitativo de alimentos fuente de fibra alimentaria, y un álbum fotográfico para identificar el tamaño de la porción. Se realizó un análisis estadístico descriptivo, y para evaluar la asociación se utilizó el test X2 y ANOVA.Resultados: el consumo promedio de fibra total de los pacientes encuestados fue de 18,8±5,9 g/d, de los cuales 14,8±4,6 g/d correspondían a fibra insoluble y 4,0±1,5 g/d a fibra soluble. Las frutas y vegetales aportaron el 82% de la fibra soluble. La mayoría (62%) de los pacientes presentaron un consumo de fibra total menor a la recomendación de la ADA, y el 60% presentó una inadecuada relación entre la ingesta de fibra insoluble y soluble.Conclusiones: es necesario aumentar el aporte de fibra dietética total, especialmente la fracción soluble en los pacientes con diabetes tipo 2, porque hay evidencias que apoyan sus beneficios.

Effect of graded levels of fiber from alfalfa meal on intestinal nutrient and energy flow, and hindgut fermentation in growing pigs1

The objective of this experiment was to determine the effects of fiber level from alfalfa meal and collection period on intestinal nutrient and energy flow, and hindgut fermentation in growing pigs. Twenty-four pigs (initial BW = 21.4 ± 1.5 kg) were prepared by T-cannula insertion into the distal ileum and allotted to 4 treatments. The pigs were provided a corn-soybean meal control diet or a diet in which corn and soybean meal were partly replaced by 5%, 10%, or 20% alfalfa meal to give the graded levels of dietary fiber during two 10-d collection periods. The BW of pigs at the start of periods 1 and 2 were 32.2 ± 2.4 and 37.7 ± 4.2 kg, respectively. The final BW at the end of period 2 was 46.8 ± 4.0 kg. The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and energy were measured. The VFA concentration was also determined in the ileal and fecal samples. Nutrient digestibility was not affected by inclusion of 5% alfalfa meal in the diet. The AID, ATTD, and hindgut fermentation of DM, carbohydrates (CHO), and GE decreased (linear, P < 0.05) as the level of alfalfa meal in the diet increased. The intestinal flow of DM, CHO, ADF, and GE increased (linear, P < 0.05) by increasing the level of dietary alfalfa. The pH in ileal digesta and concentration of acetate, propionate, and total VFA in the feces increased (linear, P < 0.01) as the level of alfalfa meal in the diet increased. From experiment period 1 to 2, ATTD and hindgut fermentation of CHO decreased (P < 0.01), whereas concentrations of propionate, valerate, and total VFA in ileal samples increased (P < 0.05). A multiple linear regression analysis, taking into account both soluble dietary fiber and insoluble dietary fiber intake, explained the variation (P < 0.01) in total tract flow of NDF (93%), ADF (84%), GE (73%), DM (71%), and CHO (62%). In conclusion, the diet containing 5% of alfalfa meal did not affect nutrient and energy digestion. Intestinal flow of CHO decreased during the 10-d collection period. The VFA concentration increased with fiber level and 10-d exposure to the experimental diets. Soluble and insoluble fibers from alfalfa meal have differential roles in nutrient digestion, which may help explain the variation observed in the intestinal flow of nutrients.

Depressive symptoms and serum lipid levels in young adult women

Accumulating data suggest that depression is associated with risk factors for cardiovascular disease, but few studies have investigated potential behavioral mediators of such associations, particularly among women. In this study of healthy young adult women (n=225), we examined associations among depressive symptoms, health behaviors, and serum lipid levels. Depressive symptoms were assessed with the 20-item Center for Epidemiologic Studies-Depression scale, and a fasting blood sample was obtained for serum lipid levels, including total cholesterol, high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C). Diet was measured using 24-h recalls, and other health behaviors (physical activity, smoking) were assessed via self-report questionnaire. Results indicated a modest negative association between depressive symptoms and LDL-C levels. Higher levels of depressive symptoms were also associated with lower total and insoluble dietary fiber intake, both of which were associated with HDL-C and LDL-C. Mediational analyses indicated a significant indirect effect of depressive symptoms on LDL-C via total and insoluble dietary fiber in unadjusted analyses, but not in adjusted analyses. The present findings suggest that depressive symptoms are inversely associated with serum LDL-C levels in young adult women, but that these associations are not likely mediated by adverse lifestyle behaviors.

Trends of the dietary fiber intake among Chinese aged 18 - 45 in nine provinces (autonomous region) from 1989 to 2006

To analyze the status and trend of dietary fiber intake and its food sources among Chinese residents aged 18 - 45 years old in 9 provinces (autonomous region), from 1989 to 2006. Twenty-four-hour dietary recall data of three consecutive days from China Health and Nutrition Survey (1989, 1991, 1993, 1997, 2000, 2004 and 2006) were used. And the 18 - 45 years old subjects with complete information on dietary survey were included. The sample size of these 7 surveys were 5597, 5596, 5323, 5485, 5308, 4144 and 3889, respectively. The trends of dietary fiber intake and food sources by time and sex were studied. From 1989 to 2000, the total of daily dietary fiber intake of 18 - 45 years old healthy residents decreased from 15.1 g/d to 11.6 g/d, insoluble dietary fiber intake decreased from 22.6 g/d to 17.8 g/d. In villages, from 1989 to 2000, the insoluble dietary fiber intake decreased 5.1 g/d in males and 5.2 g/d in females(13.2, 11.8 g in 2000, respectively;18.3, 17.0 g in 1989, respectively). In 2006, the insoluble dietary intake was 12.6 g/d in males and 11.2 g/d in females in villages. In cities, from 1989 to 2006, the insoluble dietary fiber intake was 9.4 - 11.8 g/d in males and 8.3 - 10.8 g/d in females. The total dietary fiber intake was 15.7 - 17.6 g/d in males and 13.5 - 16.4 g/d in females. The difference of insoluble and total dietary fiber intake between city and village was decreasing. In 2006, 70.6% (8.4/11.9) insoluble dietary fiber came from vegetables ((4.1 ± 3.1) g/d), wheat flour and its products ((2.6 ± 3.6) g/d), rice and its products ((1.7 ± 1.3) g/d). Dietary fiber intake among Chinese aged 18 - 45 in 9 provinces (autonomous region) decreased from 1989 to 2006. Vegetables, wheat flour, rice and their products were the major food sources of insoluble dietary fiber.

Effects of long-term soluble vs. insoluble dietary fiber intake on high-fat diet-induced obesity in C57BL/6J mice

Although most of the proposed beneficial effects of fiber consumption have been attributed to viscous and gel-forming properties of soluble fiber, it is mainly insoluble cereal fiber and whole grains that are strongly associated with reduced diabetes risk in prospective cohort studies, indicating that other unknown mechanisms are likely to be involved. We performed a long-term study investigating potential protective effects of adding soluble guar fiber (10% w/w) vs. insoluble cereal fiber (10% w/w) to an isoenergetic and macronutrient matched high-fat diet in obesity-prone C57BL/6J mice. After 45 weeks, mice fed soluble vs. insoluble fiber showed both significantly increased body weight (41.8±3.0 vs. 33.6±1.5 g, P=.03) and elevated markers of insulin resistance. In mice fed soluble fiber, energy loss via the feces was significantly lower and colonic fermentation with production of short chain fatty acids (SCFA) was markedly increased. Gene expression analysis in white adipose tissue showed significantly increased levels of the fatty acid target G-protein coupled receptor-40 in soluble fiber-fed mice. Liver gene expression in the insoluble fiber group showed a pattern consistent with increased fatty acid oxidation. The present results show that soluble vs insoluble dietary fiber added to a high-fat, Western-style diet differently affected body weight and estimates of insulin sensitivity in obesity-prone mice. Soluble fiber intake with increased SCFA production significantly contributed to digested energy, thereby potentially outweighing the well known short-term beneficial effects of soluble fiber consumption.

Cereal Fiber Improves Whole-Body Insulin Sensitivity in Overweight and Obese Women

Cereal fiber intake is linked to reduced risk of type 2 diabetes in epidemiological observations. The pathogenic background of this phenomenon is unknown. Based on recent findings, we hypothesized that intake of purified insoluble oat fiber may improve whole-body insulin sensitivity. A randomized, controlled, single-blind, cross-over study was performed, and 17 overweight or obese subjects with normal glucose metabolism were analyzed. After consumption of nine macronutrient-matched portions of fiber-enriched bread (white bread enriched with 31.2 g insoluble fiber/day) or control (white bread) over a time period of 72 h, whole-body insulin sensitivity was assessed by euglycemic-hyperinsulinemic clamp. Energy intake was individually adjusted by providing standardized liquid meals. Hydrogen breath tests were performed to control for dietary adherence. When analyzing the entire cohort, whole-body glucose disposal was improved after fiber consumption (M value 6.56 +/- 0.32 vs. 6.07 +/- 0.27 mg . min(-1) . kg(-1); P = 0.043). Thirteen subjects had increased hydrogen breath test concentrations after fiber consumption, indicating probable dietary adherence. Restricting analysis to these subjects, improvements in M value (6.85 +/- 0.34 vs. 6.06 +/- 0.32 mg . min(-1) . kg(-1); P = 0.003) and insulin sensitivity, expressed as M/I ratio (M value divided by mean serum insulin at steady state: 3.73 +/- 0.23 vs. 3.21 +/- 0.27; P = 0.02), after fiber consumption were more pronounced. Plasma lipids, serum magnesium, ghrelin, and adiponectin concentrations, as well as substrate utilization and body weight, were not significantly changed by fiber intake (P > 0.15). Increased insoluble dietary fiber intake for 3 days significantly improved whole-body insulin sensitivity. These data suggest a potential mechanism linking cereal fiber intake and reduced risk of type 2 diabetes.

Impact of cereal fibre on glucose-regulating factors

Insoluble dietary fibre intake is associated, by unknown mechanisms, with a reduced risk of type 2 diabetes. We investigated whether a short-term dietary intervention with purified insoluble fibres influences acute and delayed responses of glucose, insulin, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1. Fourteen healthy women with NGT were studied for 300 min on six to eight occasions. Subjects consumed three matched portions of control (C) or fibre-enriched bread (10.4-10.6 g/portion; wheat fibre [WF], oat fibre [OF], and, in a substudy [n=9], resistant starch [RS]) followed by control (C-C, C-WF, C-OF, C-RS) on subsequent days. Fibre enrichment accelerated the early insulin response (fibrextime interaction p=0.026 for WF, p<0.001 for OF, p=0.126 for RS; time of maximal concentration [T(max)], C 57.9+/-5.9, WF 49.3+/-2.5 [p=0.086], OF 46.1+/-2.9 [p=0.026], RS 46.7+/-5.8 min [p=0.029]). It was also associated with an earlier postprandial GIP response after OF (T(max), C 83.6+/-7.2, WF 70.7+/-6.0 [p=0.054], OF 64.3+/-6.9 [p=0.022], RS 60.0+/-5.0 [p>0.15]). Increased fibre intake for 24 h was further associated with a reduced postprandial glucose response on the following day subsequent to ingestion of a control meal (AUC(C-C) 4,140+/-401, AUC(C-WF) 2,850+/-331 [p=0.007], AUC(C-OF) 2,830+/-277 [p=0.011]), with no difference in maximal concentration and T(max) of glucose responses. No differences in insulin responses were observed 24 h after the fibre-enriched diets compared with control (p>0.15). Colonic fermentation was increased only on study days C-OF (p=0.017) and C-RS (p=0.016). The consumption of highly purified insoluble dietary fibres accelerated the acute GIP and insulin response and was further associated with enhanced postprandial carbohydrate handling the following day upon ingestion of a control meal.

Pelvic organ prolapse, constipation, and dietary fiber intake in women: A case-control study

This study was undertaken to determine whether there is an association among pelvic organ prolapse, constipation, and dietary fiber intake. Sixty consecutive women with prolapse were compared with 30 control women without prolapse. All women completed 2 validated questionnaires to assess constipation and dietary fiber intake. Multivariate analysis was performed. The risk for constipation was greater in women with prolapse than controls (odds ratio 4.03, 95% CI 1.5-11.4). Median insoluble fiber intake was significantly lower in women with prolapse (2.4 g) than controls (5.8 g, P < .01). The increased risk for constipation was reduced but remained significant after controlling for age and insoluble dietary fiber intake (odds ratio 2.9, 95% CI 1.1-13.5). Women with pelvic organ prolapse are at a higher risk for constipation than controls. This increased risk for constipation is partially explained by lower intake of dietary insoluble fiber by women with prolapse than controls.

Impact of dietary fiber on nutrient intake and lipid levels of children: The Bogalusa heart study

Age and secular trends in dietary fiber intake of children were examined using the 24-hr dietary recall. Dietary fiber intake of 5 cohorts of 10-year-olds (n=1254); 2 cohorts of 13-year-olds (n=360); and children ages 10 (n=767), 13 (n=249), 15 (n=108) and 17 (n=89) years was examined during 1976 to 1988. Race-sex distributions were similar in all age groups. Total dietary fiber intake of 10- and 13-year-old children has remained virtually the same from 1976 to 1988, even after adjusting for energy intake; averaging 12 gms or 5 gms/1000 kcal. Insoluble dietary fiber intake averaged 6 gms. No significant differences were noted in fiber intakes/1000 kcal from ages 10 to 17 years, yet blacks had higher fiber intakes than whites (5.9 gms/1000 kcal vs 5.1 gms/1000 kcal, p≤0.005). Of the total fiber consumed at all ages, 12% to 19% came from breakfast, 26% to 33% from lunch, 34% to 44% from dinner, and 24% to 29% from snacks. Consumption of vegetables/soups and breads/cereals accounted for 53% (10 years) to 70% (13 years) of the total fiber consumed. Children in the upper quartile for insoluble fiber intake/1000 kcal had significantly lower LDL-C (p≤0.0001) and VLDL-C (p≤0.05) and higher HDL-C (p≤0.0001) than those in the lower intake quartile. When children were stratified into quartiles based on fiber intake/1000 kcal the percent energy from total fat and saturated fat was lower (p≤0.0001) and percent energy from carbohydrate was higher (≤0.0001) in children with higher fiber intakes/1000 kcal. More studies are needed to document dietary fiber intakes of children and its impact on overall diet composition and cardiovascular risk factors.