Associations Of Dietary Fiber Intake Research Articles

Association between Dietary Fiber Intake and Hyperuricemia among Chinese Adults: Analysis of the China Adult Chronic Disease and Nutrition Surveillance (2015).

This study aimed to assess the association of dietary fiber intake with serum uric acid (SUA) levels and risk of hyperuricemia (HUA) among Chinese adults using the latest nationally representative data. A total of 66,427 Chinese adults aged 18 years and over from the China Adult Chronic Disease and Nutrition Surveillance in 2015 were included in this study. Dietary intakes were measured with a 3-day 24 h dietary recall and the household condiment weighing method. Mixed-effect linear and logistic regression models were used to evaluate the associations of dietary fiber intake with SUA levels and risk of HUA, respectively. Compared to the lowest intake group, the coefficient and 95% confidence in the highest intake group of total fiber were −0.06 (−0.08, −0.04) (p-trend < 0.001), −0.18 (−0.2, −0.16) (p-trend < 0.001) for cereal fiber, 0.03 (0.01, 0.04) (p-trend = 0.051) for legume fiber, 0 (−0.01, 0.02) (p-trend = 0.869) for vegetable fiber and 0.01 (−0.001, 0.04) (p-trend = 0.296) for fruit fiber. The odds ratio (OR) and 95% confidence interval (CI) of HUA for the highest vs. lowest intake group of total fiber were 0.88 (0.84, 0.91) (p-trend = 0.001), 0.67 (0.63, 0.71) (p-trend < 0.001) for cereal fiber, 1.05 (1, 1.09) (p-trend = 0.248) for legume fiber, 1.01 (0.97, 1.05) (p-trend = 0.982) for vegetable fiber and 1.06 (1, 1.12) (p-trend = 0.264) for fruit fiber. Our findings suggest that consumption of total fiber and cereal fiber were significantly inversely associated with SUA levels and HUA risk among the Chinese adult population. Developing and implementing effective public education programs are urgently needed to increase the intake of dietary fiber, especially cereal fiber among Chinese adults.

The association between dietary fiber intake and the concentrations of aldehydes in serum.

Aldehydes have been shown to be potentially carcinogenic, mutagenic, and cardiotoxic to humans. Dietary fiber reduces exposure to certain environmental pollutants and has been widely used to improve various metabolic disorders. However, the effects of dietary fiber on serum concentrations of aldehydes remain unexplored. Data was collected from the National Health and Nutrition Examination Survey (NHANES) 2013-2014. Generalized linear regression and restricted cubic spline models were performed to elucidate the association of dietary fiber intake with the serum concentration of aldehydes. After fully adjusting for age, sex, education level, race, smoking status, alcohol use, diabetes, hypertension, body mass index, energy intake, poverty-income ratio, and physical activity, dietary fiber intake had a strong negative association with serum levels of isopentanaldehyde and propanaldehyde and a positive association with serum levels of benzaldehyde. The estimated increases in the mean log2-unit (ng/mL) of aldehydes for each fold increase in dietary fiber were -0.140 (95% confidence interval [CI]: -0.195 to -0.085) for isopentanaldehyde, -0.060 (95% CI: -0.099 to -0.015) for propanaldehyde, and 0.084 (95% CI: 0.017 to 0.150) for benzaldehyde, respectively. No significant association was observed between dietary fiber intake and the concentration of any other aldehydes. These results demonstrate that dietary fiber reduces the concentration of certain aldehydes in serum.

Association of dietary fiber intake with newly-diagnosed type 2 diabetes mellitus in middle-aged Chinese population

BackgroundEpidemiological evidence concerning dietary fiber on newly-diagnosed type 2 diabetes mellitus (T2DM) is sparse. Therefore, the purpose of this study was to investigate the relationship between dietary fiber intake and newly-diagnosed T2DM in a middle-aged Chinese population.MethodsUsing data from the Hangzhou Nutrition and Health Survey collected between June 2015 and December 2016, we investigated the associations between dietary patterns and the risk of chronic non- communicable diseases. Anthropometric measurements and samples collection for biochemical assays are conducted by the well-trained staff and nurse, respectively. Multivariable logistic regression analysis was used to analyze the effect of dietary fiber intake on the risk of newly-diagnosed T2DM in crude and adjusted models.ResultsAmong 3250 participants, 182 (5.6%) people were identified as newly-diagnosed T2DM. Pearson correlation coefficients revealed a significant inverse association of total dietary fiber with BMI, SBP, DBP, HbA1c and LDL-C in all participants, participants with and without T2DM (P < 0.05). Compared with the study participants in the first quartile (Q1, the lowest consumption)of dietary fiber intake, participants in the fourth quartile (Q4) had a lower prevalence of newly-diagnosed T2DM(OR = 0.70; 95%CI:0.49-1.00; P < 0.05), after adjustment for potential confounders.ConclusionsIn this middle-aged Chinese population, higher intake of dietary fiber was significantly associated with lower risk of newly-diagnosed T2DM. However, our findings need to be confirmed in future large-scale prospective studies.

Intake of Dietary Fiber From Grains and the Risk of Hypertension in Late Midlife Women: Results From the SWAN Study.

Background: The possible effects of dietary fiber intake on hypertension have not been clarified fully. The association of dietary fiber intake with hypertension risk in midlife women was analyzed in this study.Methods: Baseline data were obtained from the Study of Women's Health Across the Nation (SWAN). Smooth curve, linear regression, and logistic regression analyses were performed to investigate the associations of four indices of daily dietary estimate (DDE) of dietary fiber (dietary fiber intake, dietary fiber intake from beans, dietary fiber intake from vegetables/fruit, and dietary fiber intake from grains) with blood pressure in midlife women. For this research purpose, diastolic blood pressure (DBP) ≥90 mmHg was defined as diastolic hypertension, and systolic blood pressure (SBP) ≥140 mmHg was defined as systolic hypertension.Results: This study included 2,519 participants with an average age of 46. The smooth curve showed approximate negative correlations between three fiber indices (DDE dietary fiber, DDE fiber from vegetables/fruit, and DDE fiber from grains) and blood pressure, including DBP and SBP (all P < 0.005). There were also approximate negative correlations between two fiber indices (DDE dietary fiber and DDE fiber from grains) and the risk of diastolic hypertension and systolic hypertension (all P < 0.05). Furthermore, multiple linear regression analysis suggested that DDE dietary fiber (Sβ = −0.057, 95% CI −0.194 – −0.012, P = 0.027), DDE fiber from vegetables/fruit (Sβ = −0.046, 95% CI −0.263 – −0.007, P = 0.039), and DDE fiber from grains (Sβ = −0.073, 95% CI −0.600 – −0.099, P = 0.006, Model 4) were still negatively correlated with DBP after adjusting for confounding factors. Only DDE fiber from grains was independently and negatively associated with SBP (Sβ = −0.060, 95% CI −0.846 – −0.093, P = 0.015) after these same confounding factors were adjusted for. Importantly, multiple logistic regression analysis suggested that only higher DDE fiber from grains was independently associated with a reduced risk of diastolic hypertension (OR = 0.848, 95% CI 0.770–0.934, P = 0.001, Model 4) and systolic hypertension (OR = 0.906, 95% CI 0.826–0.993, P = 0.034, Model 4) after the adjustments were made for confounding factors.Conclusions: We found that dietary fiber intake, especially DDE fiber from grains, contributes to a lower risk of systolic hypertension and diastolic hypertension in midlife women.

Genetically determined SCFA concentration modifies the association of dietary fiber intake with changes in bone mineral density during weight loss: The Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial

SCFAs are involved in regulation of body weight and bone health. We aimed to examine whether genetic variations related to butyrate modified the relation between dietary fiber intake and changes in bone mineral density (BMD) in response to weight-loss dietary interventions. In the 2-y Preventing Overweight Using Novel Dietary Strategies trial, 424 participants with BMD measured by DXA scan were randomly assigned to 1 of 4 diets varying in macronutrient intakes. A polygenic score (PGS) was calculated based on 7 genetic variants related to the production of butyrate for 370 of the 424 participants. SCFA PGS significantly modified the association between baseline dietary fiber intake and sex on 2-y changes in whole-body BMD (P-interaction=0.049 and 0.008). In participants with the highest tertile of SCFA PGS, higher dietary fiber intake was related to a greater increase in BMD (β: 0.0022; 95% CI: 0.0009, 0.0035; P=0.002), whereas no such association was found for participants in the lower tertiles. In the lowest tertiles of SCFA PGS, men showed a significant increase in whole-body BMD (β: 0.0280; 95% CI: 0.0112, 0.0447; P=0.002) compared with women. In the highest tertile, no significant difference was found for the change in BMD between men and women. Our data indicate that genetic variants related to butyrate modify the relations of dietary fiber intake and sex with long-term changes in BMD in response to weight-loss diet interventions.

Association of dietary fiber intake with metabolic syndrome among adult cancer survivors: a population-based cross-sectional study

Nutrient intake for adult cancer survivors is of clinical importance for managing metabolic health. Whether dietary fiber intake is associated with metabolic syndrome (MetS) or not in adult cancer survivors is uncertain. We aim to investigate the association between dietary fiber intake and MetS in adult cancer survivors using a population-based cross-sectional study. A study sample of 1301 adult cancer survivors aged more than 20 years from the sixth and seventh Korea Nutrition Examination Survey (KNHANES) from 2013 to 2018 was identified. Odds ratio (OR) and 95% confidence intervals (95% CI) were estimated from multiple logistic regression adjusted for sociodemographic factors, health behavior, and nutritional status. Among 1,301 adult cancer survivors identified from the KNHANES 2013–2018, the mean dietary fiber intake was 28.1 g/day (standard error, 0.54). Compared to the first quintile of dietary fiber intake, the adjusted ORs and 95% CIs for MetS in the second, third, fourth, and fifth quintiles of dietary fiber intake were 0.84 (0.27–2.61), 0.77 (0.16–3.74), 0.55 (0.14–2.22), and 0.26 (0.05–1.39), respectively (p value for trend = 0.0007). Our findings suggest that high dietary fiber intake is marginally associated with reduced odds of MetS in adult cancer survivors.

Dietary fiber intake from fresh and preserved food and risk of nasopharyngeal carcinoma: observational evidence from a Chinese population

BackgroundThe role of dietary fiber intake on risk of nasopharyngeal carcinoma (NPC) remains unclear. We examined the associations of dietary fiber intake on the risk of NPC adjusting for a comprehensive list of potential confounders.MethodsUsing data from a multicenter case-control study, we included 815 histologically confirmed NPC incident cases and 1502 controls in Hong Kong, China recruited in 2014–2017. Odds ratios (ORs) of NPC (cases vs controls) for dietary fiber intake from different sources at different life periods (age 13–18, age 19–30, and 10 years before recruitment) were evaluated using unconditional logistic regression, adjusting for sex, age, socioeconomic status, smoking and drinking status, occupational hazards, family history of cancer, salted fish, and total energy intake in Model 1, Epstein-Barr virus viral capsid antigen serological status in Model 2, and duration of sun exposure and circulating 25-hydroxyvitamin D in Model 3.ResultsHigher intake of total dietary fiber 10 years before recruitment was significantly associated with decreased NPC risk, with demonstrable dose-response relationship (P-values for trend = 0.001, 0.020 and 0.024 in Models 1–3, respectively). The adjusted ORs (95% CI) in the highest versus the lowest quartile were 0.51 (0.38–0.69) in Model 1, 0.48 (0.33–0.69) in Model 2, and 0.48 (0.33–0.70) in Model 3. However, the association was less clear after adjustment of other potential confounders (e.g. EBV) in the two younger periods (age of 13–18 and 19–30 years). Risks of NPC were significantly lower for dietary fiber intake from fresh vegetables and fruits and soybean products over all three periods, with dose-response relationships observed in all Models (P-values for trend for age 13–18, age 19–30 and 10 years before recruitment were, respectively, 0.002, 0.009 and 0.001 for Model1; 0.020, 0.031 and 0.003 for Model 2; and 0.022, 0.037 and 0.004 for Model 3). No clear association of NPC risk with dietary fiber intake from preserved vegetables, fruits and condiments was observed.ConclusionOur study has shown the protective role of dietary fiber from fresh food items in NPC risk, but no association for total dietary fiber intake was observed, probably because total intake also included intake of preserved food. Further studies with detailed dietary information and in prospective settings are needed to confirm this finding, and to explore the possible underlying biological mechanisms.

Dietary Fiber and Human Papillomavirus Infection among US Women: The National Health and Nutrition Examination Survey, 2003–2016

The impact of dietary fiber on human papillomavirus (HPV) infection is still underway. The aim of our study was to investigate the association between intake of dietary fiber and HPV infection. Overall, 14,151 eligible women, aged 18–59 years old, who submitted an adequate sample for HPV test, were collected from an ongoing, large scale population-based survey for seven cycles. The association of dietary fiber intake and HPV infection was assessed in multivariate logistic models. For sensitivity analysis, generalized additive model (GAM) and smooth curve fitting were employed to verify the robustness of the results. Among 14,151 eligible participants, intake of dietary fiber was negatively associated with HPV infection. Each additional increase in log10 dietary fiber consumption was associated with a 57% lower risk of HPV infection (OR, 0.43; 95% CI 0.38–0.48). The result is stable in minimally and fully adjusted model. The possibility of nonlinear association of dietary fiber and HPV infection has been excluded by GAM and smooth curve fitting. There was an inverse linear correlation between intake of dietary fiber and HPV infection. Our findings obtained from NHANES dataset suggested that increasing dietary fiber consumption may be associated with the prevalence of HPV infection.

Dietary Fiber, Genetic Variations of Gut Microbiota-derived Short-chain Fatty Acids, and Bone Health in UK Biobank

Dietary fiber intake may relate to bone health. To investigate whether dietary fiber intake is associated with bone mineral density (BMD), and the modification effect of genetic variations related to gut microbiota-derived short-chain fatty acids (SCFAs). The associations of dietary fiber intake with estimated BMD derived from heel ultrasound and fractures were assessed in 224 630 and 384 134 participants from the UK Biobank. UK Biobank. Estimated BMD derived from heel ultrasound. Higher dietary fiber intake (per standard deviation) was significantly associated with higher heel-BMD (β [standard error] = 0.0047 [0.0003], P = 1.10 × 10-54). Similarly significant associations were observed for all the fiber subtypes including cereal, fruit (dried and raw), and vegetable (cooked and raw) (all P < .05). A positive association was found in both women and men but more marked among men except for dietary fiber in cooked vegetables (all Pinteraction < .05). A protective association was found between dietary fiber intake and hip fracture (hazard ratio, 95% confidence interval: 0.94, 0.89-0.99; P = 3.0 × 10-2). In addition, the association between dietary fiber and heel BMD was modified by genetically determined SCFA propionate production (Pinteraction = 5.1 × 10-3). The protective association between dietary fiber and heel BMD was more pronounced among participants with lower genetically determined propionate production. Our results indicate that greater intakes of total dietary fiber and subtypes from various food sources are associated with higher heel-BMD. Participants with lower genetically determined propionate production may benefit more from taking more dietary fiber.

Dietary Fiber Is Inversely Associated With Depressive Symptoms in Premenopausal Women.

BackgroundAn inverse association between dietary fiber intake and depressive symptoms was reported in the general population, but this association is unstudied in midlife women. This study was designed to investigate the association of dietary fiber intake with depressive symptoms in midlife women.MethodsAnalyses for this cross-sectional study were performed on baseline assessment of the Study of Women’s Health Across the Nation (SWAN). Linear regressions were used to examine the association of fiber intake with Center for Epidemiological Studies-Depression (CES-D) score. Logistic regression and restricted cubic spline analyses were used to examine the association between fiber intake and depressive symptoms (CES-D score ≥ 16).ResultsA total of 3054 midlife women in our study were stratified into premenopausal women and early perimenopausal women by menstrual bleeding patterns. In premenopausal women, dietary fiber intake was inversely associated with CES-D scores in unadjusted, age-, education-, race/ethnicity-, total family income-, BMI-, sport-, use of antidepressant-, dietary total caloric intake-, SHBG-, and FSH-adjusted linear regression model. The fully adjusted regression coefficient with 95% confidence intervals (CIs) of fiber intakes was −0.146 (−0.235, −0.058) for CES-D score. Fiber intake was inversely associated with depressive symptoms (CES-D score ≥ 16) in crude and fully adjusted logistic regression model. The fully adjusted odds ratios (ORs) with 95% CI of depressive symptoms was 0.483 (0.314–0.745) in quartile 4 compared with quartile 1 for fiber intake. However, in early perimenopausal women, dietary fiber intake was not statistically significantly associated with depressive symptoms.ConclusionDietary fiber is inversely associated with depressive symptoms in premenopausal women, but not in early perimenopausal women.

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. The aim of the present study was to examine their associations in the U.S. general adult population. Data from the National Health and Nutrition Examination Survey (NHANES) 2009 to 2014 were used. Dietary fiber intake was extracted through two 24 h dietary recall interviews. Hyperuricemia was defined by cut-off values of 7.0 mg dL-1 for men and 6.0 mg dL-1 for women. Multivariable logistic regression models and restricted cubic spline models were applied to explore the associations between dietary intakes of total, cereal, fruit and vegetable fiber and the risk of hyperuricemia. A total of 12 869 participants aged 20 years or older were included in the present study. The multivariable odds ratio (OR) and 95% confidence interval (CI) of hyperuricemia for the highest vs. lowest quartile intake of total fiber were 0.58 (0.46-0.74), 0.61 (0.52-0.74) for cereal fiber, 0.94 (0.76-1.16) for fruit fiber and 0.95 (0.76-1.18) for vegetable fiber. The inverse associations between dietary intakes of total fiber and cereal fiber and the risk of hyperuricemia were observed in men. In stratified analysis by age (<45 years, ≥45 years), the inverse association between total fiber intake and the risk of hyperuricemia was consistent, while cereal fiber intake was only inversely associated with hyperuricemia among participants <45 years old. Dose-response analyses showed that the risk of hyperuricemia was associated with dietary intake of total fiber in a nonlinear manner, whereas the relationship was linear for cereal fiber intake. In conclusion, dietary intakes of total fiber and cereal fiber were inversely associated with the risk of hyperuricemia in the U.S. adult population.

Dietary fiber intake and mortality in a Mediterranean population: the “Seguimiento Universidad de Navarra” (SUN) project

To prospectively assess the association of dietary fiber intake (from different dietary sources) with all-cause mortality in a Mediterranean cohort. We assessed 19,703 participants of the SUN (Seguimiento Universidad de Navarra) cohort (mean follow-up: 10.1years). A validated 136-item FFQ was administered at baseline. We used Cox proportional hazards models adjusted for multiple socio-demographic, anthropometric, lifestyle factors, and prevalent conditions at baseline. We observed 323 deaths during 198,341 person-years of follow-up. A significantly inverse linear trend in Cox models was observed for the association of total dietary fiber intake and all-cause mortality after adjustment for confounders (p for trend 0.017). Each additional intake of 5g/1000kcal of dietary fiber was associated with a 9% relative reduction in all-cause mortality risk (HR 0.91, 95% CI 0.84-0.99). Considering separate dietary sources in separate models, a significant inverse trend was apparent for fiber derived from vegetables (p for trend 0.001), but it was non-significant for fiber derived from fruit, legumes, cereals, or other sources. Soluble fiber was significantly inversely associated with all-cause mortality in the fully adjusted model (p for trend 0.007), and insoluble fiber was marginally significant (p for trend 0.08). A higher intake of total dietary fiber, and particularly fiber from vegetables, was related to a reduced all-cause mortality in our Mediterranean cohort. Dietary messages to increase the consumption of dietary patterns rich in fiber-rich foods should be broadly disseminated to decrease the alarming rate of chronic diseases and its derived mortality.

Association of dietary fiber intake with general and abdominal obesity in children and adolescents: The Weight disorder survey of the CASPIAN-IV Study

BACKGROUND: Dietary fiber intake might have a protective role against obesity. The aim of this study is to explore the association of dietary fiber intake with general and abdominal obesity in Iranian children and adolescents. MATERIAL AND METHODS: This cross-sectional nationwide study was conducted on 5187 students aged 6–18 years, living in 30 provinces of Iran. They were selected randomly through cluster sampling method. Data on demographic and anthropometric indices including weight, height and waist circumference (WC) were collected by trained interviewers. A valid and reliable 168-item semi-quantitative food frequency questionnaire (FFQ) was used to assess student’s usual dietary intake including total dietary fiber. All dietary reports were converted to daily consumption (g/day) using household measures for different portion sizes. Food items were then converted to their nutrient content. Energy-adjusted dietary fiber intake (g/1000 kcal/day) was also calculated using the energy density method. Multivariate regression models were applied to explore the association between dietary fiber intake and anthropometric indices. RESULTS: The mean and standard deviation (SD) for age of participants were 11.40 (3.20) years. Of 5187 students, 52.6% were boys and 72.5% were from urban areas (participation rate: 79.7%). White bread (32.5%), white rice (17.1%) and potato (11.7%) were the most common sources of dietary fiber intake. Each 1 g/1000 Kcal increase in dietary fiber intake was significantly associated with lower weight and waist circumference (P = 0.006 and P = 0.008, respectively). CONCLUSION: Higher fiber intake was associated with lower anthropometric indices including weight and WC. Increased fiber intake should be encouraged for children and adolescents.

The Association of Dietary Fiber Intake with Cardiometabolic Risk in Four Countries across the Epidemiologic Transition.

The greatest burden of cardiovascular disease is now carried by developing countries with cardiometabolic conditions such as metabolic syndrome, obesity and inflammation believed to be the driving force behind this epidemic. Dietary fiber is known to have protective effects against obesity, type 2 diabetes, cardiovascular disease and the metabolic syndrome. Considering the emerging prevalence of these cardiometabolic disease states across the epidemiologic transition, the objective of this study is to explore these associations of dietary fiber with cardiometabolic risk factors in four countries across the epidemiologic transition. We examined population-based samples of men and women, aged 25–45 of African origin from Ghana, Jamaica, the Seychelles and the USA. Ghanaians had the lowest prevalence of obesity (10%), while Jamaicans had the lowest prevalence of metabolic syndrome (5%) across all the sites. Participants from the US presented with the highest prevalence of obesity (52%), and metabolic syndrome (22%). Overall, the Ghanaians consumed the highest dietary fiber (24.9 ± 9.7 g), followed by Jamaica (16.0 ± 8.3 g), the Seychelles (13.6 ± 7.2 g) and the lowest in the USA (14.2 ± 7.1 g). Consequently, 43% of Ghanaians met the fiber dietary guidelines (14 g/1000 kcal/day), 9% of Jamaicans, 6% of Seychellois, and only 3% of US adults. Across all sites, cardiometabolic risk (metabolic syndrome, inflammation and obesity) was inversely associated with dietary fiber intake, such that the prevalence of metabolic syndrome was 13% for those in the lowest quartile of fiber intake, compared to 9% those in the highest quartile of fiber intake. Notably, twice as many of participants (38%) in the lowest quartile were obese compared to those in the highest quartile of fiber intake (18%). These findings further support the need to incorporate strategies and policies to promote increased dietary fiber intake as one component for the prevention of cardiometabolic risk in all countries spanning the epidemiologic transition.

Dietary fiber and health outcomes: an umbrella review of systematic reviews and meta-analyses

Several studies have suggested that higher consumption of dietary fiber is beneficial for a variety of health outcomes. However, many results have been inconclusive and, to our knowledge, there has been no attempt to systematically capture the breadth of outcomes associated with dietary fiber intake or to systematically assess the quality and the strength of the evidence on the associations of dietary fiber intake and different health outcomes or medical conditions. The aim of this study was to describe the diverse health outcomes convincingly associated with dietary fiber consumption. This was an umbrella review of systematic reviews with meta-analysis of observational studies. For each association, random-effects summary effect size, 95% CIs, and 95% prediction intervals were estimated. We also assessed heterogeneity, evidence for small-study effect, and evidence for excess significance bias. We used these metrics to evaluate the credibility of the identified evidence. Our literature search identified 1351 abstracts. Of these, 18 meta-analyses including a total of 298 prospective observational studies and 21 outcomes were included. Outcomes studied included cancer and precancer lesions (n=12), cardiovascular diseases (CVDs; n=3), all-cause and specific-cause mortality (n=4), type 2 diabetes (n=1), and Crohn disease (n=1). Overall, 6 (29%) of the 21 eligible outcomes reported highly significant summary results (P<1×10-6); these included CVD and CVD mortality, coronary artery disease, pancreatic cancer, and gastric cancer. Overall, 3 of 21 (14%) outcomes presented convincing evidence (pancreatic cancer, CVD mortality, and all-cause mortality), but only CVD and all-cause mortality were based on prospective studies. Two other outcomes (10%), CVD and coronary artery disease, presented highly suggestive evidence based on prospective studies. Our results support dietary recommendations that promote higher fiber intake as part of a healthy diet.

Dietary fiber intake and risk of metabolic syndrome: A meta-analysis of observational studies

Epidemiological studies show inconsistent findings on the association of dietary fiber intake with risk of metabolic syndrome (MetS). Herein, we aim to conduct a meta-analysis of published studies to determine the role of dietary fiber in prevention of MetS. A systematical search in PubMed and Embase databases through December 2016, together with reference scrutiny of relevant literature, was performed to identify studies for inclusion. We aggregated the odds ratios (ORs) with 95% confidence intervals (CIs) of MetS using a random effect model. Dose-response relationship between fiber intake and MetS was also evaluated. This meta-analysis included 8 cross-sectional and 3 cohort studies, totaling 28,241 participants and 9140 MetS cases. The highest versus lowest fiber intake was associated with a reduced risk of MetS (OR: 0.85, 95% CI: 0.79-0.92; P=0.005), with moderate heterogeneity (I2=64%, P=0.001) across studies. The benefit of fiber intake was significant among cross-sectional studies (OR: 0.85, 95% CI: 0.78-0.92; P<0.001) but not among cohort studies (OR: 0.86, 95% CI: 0.70-1.06; P=0.16). In dose-response analysis, we found a curvilinear relationship between fiber consumption and prevalence of MetS. Compared with non-fiber intake, the ORs (95% CIs) of MetS across fiber intake levels were 0.85 (0.79-0.91), 0.76 (0.67-0.85), 0.73 (0.65-0.83), and 0.73 (0.65-0.82) for 10, 20, 30, and 40g/d, respectively. Dietary fiber intake is associated with less likelihood of having MetS. Additional large, prospective studies are warranted to enhance our findings.

Association of dietary fiber intake and gut microbiota in healthy adults.

1569 Background: Increasing evidence has shown that gut microbiota alterations may play a role in colorectal cancer risk. Diet, particularly fiber intake, may modify gut microbiota composition, which may consequently impact cancer risk development. We investigated the relationship between dietary fiber intake and gut microbiota in healthy humans. Methods: Using 16S rRNA gene sequencing, we assessed gut microbiota in fecal samples from 151 healthy adults in two independent study populations: Study A, n = 75 (healthy controls from a colorectal cancer case-control study), and Study B, n = 76 (polyp-free subjects from a cross-sectional colonoscopy study). We calculated energy-adjusted total dietary fiber intake of participants based on food frequency questionnaires. For each study population, we evaluated the relationship between quartiles of higher fiber intake as a continuous ordinal variable, and global gut microbiota community composition (via PERMANOVA of weighted UniFrac distance) and specific taxon abundance (via DESeq2). Results: We found that fiber intake was significantly associated with overall microbial community composition in Study B (p = 0.003) but not Study A (p = 0.68), after adjustment for age, sex, race, body mass index, and cigarette smoking. In a taxonomy-based meta-analysis of these two study populations, higher fiber intake was associated with lower abundance of genus Actinomyces (fold change [FC] = 0.769, p = 0.003), and higher abundance of genera Faecalibacterium (FC = 1.153, p = 0.03), Lachnospira (FC = 1.167, p = 0.04), and SMB53 (FC = 1.201, p = 0.05). A species-level meta-analysis showed an association between higher fiber intake and higher abundance of Faecalibacterium prausnitzii (FC = 1.165, p = 0.03) and lower abundance of Ruminococcus bromii (FC = 0.828, p = 0.08). Conclusions: Our results suggest that higher intake of dietary fiber may alter gut microbiota in healthy adults. Given the potentially modifiable nature of the gut microbiota through diet, these findings warrant further study of diet-microbiota based colorectal cancer prevention strategies.

Cardiometabolic Risk Factors Are Associated with High Urinary Enterolactone Concentration, Independent of Urinary Enterodiol Concentration and Dietary Fiber Intake in Adults

The study objective was to evaluate independent and interactive associations of dietary fiber intake and high urinary enterolignans with cardiometabolic risk factors. The analysis included 2260 adults (≥20 y of age) from the 2003–2010 NHANES. Logistic regression models were used to evaluate obesity and clinically defined cardiometabolic risk factors in relation to dietary fiber intake and urinary enterolignan concentrations. Three sets of models were created: 1) independent associations, 2) mutually adjusted associations, and 3) interactions. Models were adjusted for age, gender, race/ethnicity, education, smoking status, and energy intake. High concentrations were considered to be above the 90th percentile of urinary enterolignan concentrations. Increasing dietary fiber intake was associated with high blood pressure (P = 0.02) and low serum HDL cholesterol (P-trend = 0.03). High urinary enterodiol concentration was not associated with obesity or cardiometabolic risk factors. High urinary enterolactone concentration was inversely associated with obesity (OR: 0.44; 95% CI: 0.29, 0.66), abdominal obesity (OR: 0.58; 95% CI: 0.39, 0.87), high serum C-reactive protein (CRP; OR: 0.52; 95% CI: 0.37, 0.74), high serum triglycerides (OR: 0.39; 95% CI: 0.23, 0.61), low serum HDL cholesterol (OR: 0.37; 95% CI: 0.23, 0.61), and metabolic syndrome (OR: 0.47; 95% CI: 0.30, 0.74). In mutually adjusted models, enterolactone associations observed in independent models remained similar, but associations for dietary fiber intake were attenuated, with the exception of blood pressure. In interaction models, there were 2 significant interactions: between high urinary enterodiol concentration and dietary fiber intake for high serum CRP (P = 0.04) and high plasma glucose (P = 0.04). Overall, being in the highest 10% of urinary enterolactone concentration was associated with cardiometabolic risk factors, independent of dietary fiber intake and enterodiol concentration. Future studies are warranted to evaluate physiologic actions of enterolactone or aspects of the gut microbial profile responsible for lignan metabolism to enterolactone.

Associations between Dietary Fiber and Colorectal Polyp Risk Differ by Polyp Type and Smoking Status

The association of dietary fiber intake with colorectal cancer risk is established. However, the association may differ between cigarette smokers and nonsmokers. We evaluated this hypothesis in a large colonoscopy-based case-control study. Dietary fiber intakes were estimated by self-administered food frequency questionnaire. Unconditional logistic regression analysis was used to estimate ORs and 95% CIs with adjustment for potential confounders. Analysis also was stratified by cigarette smoking and sex. High dietary fiber intake was associated with reduced risk of colorectal polyps (P-trend = 0.003). This association was found to be stronger among cigarette smokers (P-trend = 0.006) than nonsmokers (P-trend = 0.21), although the test for multiplicative interaction was not statistically significant (P = 0.11). This pattern of association was more evident for high-risk adenomatous polyps (ADs), defined as advanced or multiple ADs (P-interaction smoking and dietary fiber intake = 0.09). Among cigarette smokers who smoked ≥23 y, a 38% reduced risk of high-risk ADs was found to be associated with high intake of dietary fiber compared with those in the lowest quartile fiber intake group (P-trend = 0.004). No inverse association with dietary fiber intake was observed for low-risk ADs, defined as single nonadvanced ADs. Cigarette smoking may modify the association of dietary fiber intake with the risk of colorectal polyps, especially high-risk ADs, a well-established precursor of colorectal cancer.

No association of dietary fiber intake with inflammation or arterial stiffness in youth with type 1 diabetes

AimTo examine the association of dietary fiber intake with inflammation and arterial stiffness among youth with type 1 diabetes (T1D) in the US. MethodsData are from youth≥10years old with clinically diagnosed T1D for≥3months and≥1 positive diabetes autoantibody in the SEARCH for Diabetes in Youth Study. Fiber intake was assessed by food frequency questionnaire with measurement error (ME) accounted for by structural sub-models derived using additional 24-h dietary recall data in a calibration sample and the respective exposure-disease model covariates. Markers of inflammation, measured at baseline, included IL-6 (n=1405), CRP (n=1387), and fibrinogen (n=1340); markers of arterial stiffness, measured approximately 19 months post-baseline, were available in a subset of participants and included augmentation index (n=180), pulse wave velocity (n=184), and brachial distensibility (n=177). ResultsMean (SD) T1D duration was 47.9 (43.2) months; 12.5% of participants were obese. Mean (SD) ME-adjusted fiber intake was 15 (2.8) g/day. In multivariable analyses, fiber intake was not associated with inflammation or arterial stiffness. ConclusionAmong youth with T1D, fiber intake does not meet recommendations and is not associated with measures of systemic inflammation or vascular stiffness. Further research is needed to evaluate whether fiber is associated with these outcomes in older individuals with T1D or among individuals with higher intakes than those observed in the present study.