High Intake Of Cereal Fiber Research Articles

Abstract 2207: Fiber intake and risk of lethal prostate cancer among men at increased genetic risk

Abstract Introduction High fiber intake from grains may lower advanced prostate cancer risk by enhancing insulin sensitivity, lowering insulin-like growth factor 1 and systemic inflammation. Whether a high-fiber diet can lower risk of metastatic disease and prostate cancer death in men at high genetic risk is unclear. Methods Using a new 400-SNP polygenic risk score (PRS) for prostate cancer, we quantified the genetic risk of 10,269 men with available genotype data in the Health Professionals Follow-up Study, followed between 1993 and 2019. Men in the top 50-100% PRS category were considered high-risk and included for analysis. Total fiber intake and different sources (cereal, fruits, vegetables) were assessed by validated food frequency questionnaires. Overall and lethal prostate cancer (metastatic disease/prostate cancer death) were analyzed using Cox proportional hazards models estimating hazard ratios (HRs) and 95% confidence intervals (CIs). Results During 26 years of follow-up, we recorded 1,494 overall and 174 lethal prostate cancer events in the high genetic risk group. As expected, no associations were observed fiber intake with risk of overall prostate cancer. For lethal prostate cancer, the results varied according to the source of fiber. Higher cereal fiber intake was associated with a lower risk of lethal prostate cancer (per 3 g/d higher intake: 0.81 [0.68, 0.97], P-trend=0.02). We further observed a higher disease risk among men with higher fruit fiber intake (per 3g/d higher intake: 1.18 [1.02, 1.36], P-trend=0.03). The associations remained similar when mutually adjusted for each fiber type. No associations were observed for total or vegetable fiber intake. Conclusion In this analysis of men at high prostate cancer genetic risk, we observed that higher cereal fiber intake was associated with lower lethal prostate cancer risk, whereas higher fruit fiber intake showed an opposite trend. Further studies in different populations and investigations into the underlying mechanisms are needed. Fiber intake with risk of overall and lethal prostate cancer among men at high genetic risk. Fiber type Overall prostate cancer: No.event/PY Overall prostate cancer: HR (95% CI) Lethal prostate cancer: No.event/PY Lethal prostate cancer: HR (95% CI) All fiber, g/d T1, median=15.8 490/66047 ref. 42/73826 ref. T2, median=21.8 484/62237 0.96 (0.83-1.11) 61/69849 1.16 (0.77-1.75) T3, median=29.9 520/67374 1.02 (0.86-1.21) 71/75242 1.24 (0.75-2.05) Per 3 g/d 0.98 (0.96-1.01) 1.00 (0.92-1.08) P for trend 0.27 0.93 Cereal fiber, g/d T1, median=4.6 491/63911 ref. 49/72367 ref. T2, median=6.7 512/66251 1.04 (0.91-1.20) 76/73384 1.30 (0.90-1.87) T3, median=9.4 491/65496 0.92 (0.80-1.06) 49/73166 0.75 (0.50-1.12) Per 3 g/d 0.96 (0.90-1.01) 0.81 (0.68-0.97) P for trend 0.14 0.02 Fruit fiber, g/d T1, median=2.5 471/66306 ref. 33/74056 ref. T2, median=4.5 514/63268 1.06 (0.92-1.22) 51/70430 1.21 (0.76-1.91) T3, median=7.2 509/66085 1.00 (0.86-1.16) 90/74431 1.84 (1.18-2.87) Per 3 g/d 0.97 (0.91-1.03) 1.18 (1.02-1.36) P for trend 0.34 0.03 Vegetable fiber, g/d T1, median=4.8 481/64139 ref. 51/71594 ref. T2, median=6.9 505/64938 1.04 (0.91-1.20) 66/72291 1.22 (0.84-1.78) T3, median=9.6 508/66581 1.04 (0.90-1.20) 57/75031 0.98 (0.65-1.45) Per 3 g/d 0.99 (0.93-1.05) 0.97 (0.82-1.15) P for trend 0.72 0.74 Citation Format: Yiwen Zhang, Konrad H. Stopsack, Lorelei A. Mucci, Edward Giovannucci, Anna Plym. Fiber intake and risk of lethal prostate cancer among men at increased genetic risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2207.

Evaluating an Intervention to Increase Cereal Fiber Intake in Children: A Randomized Controlled Feasibility Trial

ABSTRACTBackgroundObservational studies have shown that higher cereal fiber intake is associated with reduced type 2 diabetes risk. However, it remains uncertain whether this association is causal.ObjectiveThis study evaluated the feasibility of an intervention to increase cereal fiber intake in children using breakfast cereals.MethodsThe study was a 2-arm parallel group randomized controlled trial in 9–10-y-old children, who received free supplies of high-fiber breakfast cereals (>3.5 g/portion) or low-fiber breakfast cereals (<1.0 g/portion) to eat daily for 1 mo with behavioral support to promote adherence. Children provided baseline and 1-mo fasting blood samples, physical measurements, and 24-h dietary recalls. The primary outcome was the group difference in change in plasma total alkylresorcinol (AR) concentration; secondary outcomes were group differences in nutrient intakes and adiposity indices. Analyses (complete case and multiple imputation) were conducted by regressing the final AR concentration on baseline AR in models adjusted for sex, ethnicity, age, and school (random effect).ResultsTwo-hundred seventy-two children were randomly assigned (137 receiving a low-fiber and 135 a high-fiber diet) and 193 (71%) provided fasting blood samples at baseline and follow-up. Among randomized participants, median (IQR) of baseline AR was 43.1 (24.6–85.5) nmol/L and of cereal fiber intake was 4.5 (2.7–6.4) g; 87% of participants reported consuming the cereal on most or all days. Compared with changes in the low-fiber group, the high-fiber group had greater increases in AR (40.7 nmol/L; 95% CI: 21.7, 59.8 nmol/L, P < 0.0001) and in reported cereal fiber intake (2.9g/d; 95% CI: 2.0, 3.7 g; P < 0.0001). There were no appreciable differences in other secondary outcomes.ConclusionsWe have developed a simple and acceptable nutritional intervention that increases markers of daily cereal fiber intake in children. This intervention could be used to test whether increases in cereal fiber intake in children might reduce insulin resistance. This trial was registered at www.isrctn.com as ISRCTN33260236.

Dietary Fiber Intake and Endometrial Cancer Risk: A Systematic Review and Meta-Analysis.

Epidemiological studies are inconclusive regarding the association between dietary fiber intake and endometrial cancer risk. Thus, we aimed to conduct a meta-analysis to clarify the association between dietary fiber and endometrial cancer risk. We searched the PubMed and ISI Web databases for relevant studies through March 2018. The association between dietary fiber and endometrial cancer risk was evaluated by conducting a meta-analysis including 3 cohort and 12 case–control studies. A significant negative association was observed between total dietary fiber intake and endometrial cancer risk in 11 case–control studies (odds ratios (OR) 0.76, 95% confidence interval (CI): 0.64–0.89, I2 = 35.2%, p = 0.117), but a marginal positive association was observed in three cohort studies (relative risk (RR) 1.22, 95% CI: 1.00–1.49, I2 = 0.0%, p = 0.995). Particularly, a negative association was observed in North America (OR = 0.70, 95% CI: 0.59–0.83, I2 = 8.9%, p = 0.362). In addition, a positive association was observed in cereal fiber (RR = 1.26, 95% CI: 1.03–1.52, I2 = 0.0%, p = 0.530, 3 cohort studies) and a negative association was observed in vegetable fiber (OR = 0.74, 95% CI: 0.58–0.94, I2 = 0.0%, p = 0.445, 3 case–control studies). In conclusion, negative associations with endometrial cancer risk were observed for higher total dietary fiber intake and higher vegetable fiber intake in the case–control studies. However, results from the cohort studies suggested positive relationships of higher total fiber intake and higher cereal fiber intake with endometrial cancer risk.

Preventive role of dietary fiber in gastric cardia cancers.

The incidence of adenocarcinoma of the esophagus and gastric cardia is increasing. Many factors are presumed to be associated: symptoms of gastroesophageal reflux disease, tobacco use, alcohol consumption, dietary factors, and obesity. A recent large population-based case-control study evaluated the association between dietary fiber intake and cancers of the gastric cardia and esophagus. This interesting study indicated that high intake of cereal fiber may significantly decrease the risk of gastric cardia cancer. More research is needed on this topic in the hope that dietary intake may decrease the incidence of these cancers.

Fiber and Magnesium Intake and Incidence of Type 2 Diabetes

Prospective studies on fiber and magnesium intake and risk of type 2 diabetes mellitus were inconsistent. We examined associations between fiber and magnesium intake and risk of type 2 diabetes and summarized existing prospective studies by meta-analysis. We conducted a prospective cohort study of 9702 men and 15 365 women aged 35 to 65 years who were observed for incident diabetes from 1994 to 2005. Dietary intake of fiber and magnesium were measured with a validated food-frequency questionnaire. We estimated the relative risk (RR) by means of Cox proportional hazards analysis. We searched PubMed through May 2006 for prospective cohort studies of fiber and magnesium intake and risk of type 2 diabetes. We identified 9 cohort studies of fiber and 8 studies of magnesium intake and calculated summary RRs by means of a random-effects model. During 176 117 person-years of follow-up, we observed 844 incident cases of type 2 diabetes in the European Prospective Investigation Into Cancer and Nutrition-Potsdam. Higher cereal fiber intake was inversely associated with diabetes risk (RR for extreme quintiles, 0.72 [95% confidence interval [CI], 0.56-0.93]), while fruit fiber (0.89 [95% CI, 0.70-1.13]) and vegetable fiber (0.93 [95% CI, 0.74-1.17]) were not significantly associated. Meta-analyses showed a reduced diabetes risk with higher cereal fiber intake (RR for extreme categories, 0.67 [95% CI, 0.62-0.72]), but no significant associations for fruit (0.96 [95% CI, 0.88-1.04]) and vegetable fiber (1.04 [95% CI, 0.94-1.15]). Magnesium intake was not related to diabetes risk in the European Prospective Investigation Into Cancer and Nutrition-Potsdam (RR for extreme quintiles, 0.99 [95% CI, 0.78-1.26]); however, meta-analysis showed a significant inverse association (RR for extreme categories, 0.77 [95% CI, 0.72-0.84]). Higher cereal fiber and magnesium intakes may decrease diabetes risk.

The long‐term effect of cereal fiber on weight, fasting glucose, insulin, cholesterol, triglycerides and free fatty acids in hyperinsulinemic humans

Canada Epidemiological studies have shown that a high intake of cereal fiber is associated with reduced plasma insulin and reduced weight gain. However, long-term clinical studies establishing causation have not been conducted. We hypothesized that a long-term increase in cereal fiber intake in hyperinsulinemic humans would result in reduced plasma glucose, insulin, FFA, and weight. Twenty seven hyperinsulinemic subjects were randomized to receive a control (C) (n=13) or fiber (F) (24g) (n=14) cereal daily for 1 year. Body weight was measured monthly and fasting blood samples collected at baseline, 3, 6, 9, and 12 months. There was no significant difference between the two treatments in change in weight or fasting cholesterol, triglycerides (TG) or FFA. There was a significant treatment X time interaction for change in fasting glucose (p=0.03) and insulin (p=0.05). Fasting glucose increased in the C group and decreased in the F group. Conversely, fasting insulin decreased in the C group and increased in the F group. In conclusion, a daily increase in cereal fiber intake may improve beta cell function.

Whole-Grain, Bran, and Cereal Fiber Intakes and Markers of Systemic Inflammation in Diabetic Women

To evaluate the dietary predictors for the markers of systemic inflammation and endothelial dysfunction in patients with type 2 diabetes. We examined whether intakes of whole grains and dietary fiber were associated with inflammatory indicators among 902 diabetic women in the Nurses' Health Study. After adjustment for age, BMI, lifestyle, and dietary covariates, intakes of whole grains and bran were both associated with significantly decreasing trends of C-reactive protein (CRP) (P for trend = 0.03 and 0.007, respectively) and tumor necrosis factor-alpha receptor 2 (TNF-R2) (P for trend = 0.017 and 0.06). High intake of cereal fiber was also inversely associated with the lower levels of CRP (P for trend = 0.03) and TNF-R2 (P for trend = 0.01). The concentrations of CRP and TNF-R2 were 18 and 8% lower in the highest quintile of cereal fiber as compared with the lowest quintile. Dietary glycemic index was positively associated with CRP (P for trend = 0.04) and TNF-R2 (P for trend = 0.0008) levels. The concentrations of CRP and TNF-R2 were 32 and 11% higher, respectively, in the highest quintile of dietary glycemic index as compared with the lowest quintile. Our data indicate that whole grains and a low-glycemic index diet may reduce systemic inflammation among women with type 2 diabetes.

Dietary Glycemic Index, Glycemic Load, Cereal Fiber, and Plasma Adiponectin Concentration in Diabetic Men

Adiponectin may improve insulin sensitivity, reduce inflammation, and ameliorate glycemic control. However, few studies have evaluated dietary predictors of plasma adiponectin levels, especially among subjects with type 2 diabetes. To examine the associations of dietary glycemic load, glycemic index, and fibers with plasma adiponectin levels, we conducted a cross-sectional analysis in 780 diabetic men from the Health Professionals' Follow-up Study. Dietary information was obtained in 1986, 1990, and 1994 using semiquantitative food-frequency questionnaires. After adjustment for age, BMI, smoking, alcohol consumption, physical activity, aspirin use, HbA(1c), history of hypertension or hypercholesterolemia, and fiber intake, dietary glycemic index and glycemic load were inversely associated with plasma adiponectin in a dose-dependent fashion (P for trend = 0.005 for glycemic index and 0.004 for glycemic load). Adiponectin levels were 13% lower in the highest quintile of dietary glycemic index than in the lowest quintile. For dietary glycemic load, adiponectin levels were 18% lower in the highest quintile than in the lowest. In contrast, high intake of cereal fiber was associated with increased plasma adiponectin levels, adjusting for lifestyle factors and dietary glycemic load (P for trend = 0.003). Adiponectin levels were 19% higher in the highest quintile than in the lowest quintile. Higher magnesium intake was also associated with increased plasma adiponectin. Diets low in glycemic load and high in fiber may increase plasma adiponectin concentrations in diabetic patients.

Cereal, fruit, and vegetable fiber intake and the risk of cardiovascular disease in elderly individuals.

People older than 65 years are the fastest-growing segment of the population and account for the majority of cardiovascular disease (CVD) morbidity, mortality, and health care expenditures. Additionally, the influence of dietary habits on risk may be less pronounced in elderly persons, when atherosclerosis is more advanced. However, few data address the influence of diet on CVD risk in this population. To determine whether fiber consumption from fruit, vegetable, and cereal sources (including whole grains and bran) is associated with incident CVD in elderly persons. Prospective cohort study conducted from 1989 to June 2000. Population-based, multicenter study among 3588 men and women aged 65 years or older and free of known CVD at baseline in 1989-1990. Usual dietary fiber consumption was assessed at baseline (mean participant age, 72 years) using a 99-item food frequency questionnaire. Incident CVD (combined stroke, ischemic heart disease death, and nonfatal myocardial infarction). During 8.6 years mean follow-up, there were 811 incident CVD events. After adjustment for age, sex, education, diabetes, ever smoking, pack-years of smoking, daily physical activity, exercise intensity, alcohol intake, and fruit and vegetable fiber consumption, cereal fiber consumption was inversely associated with incident CVD (P for trend =.02), with 21% lower risk (hazard ratio [HR], 0.79; 95% confidence interval [CI], 0.62-0.99) in the highest quintile of intake, compared with the lowest quintile. In similar analyses, neither fruit fiber intake (P for trend =.98) nor vegetable fiber intake (P for trend =.95) were associated with incident CVD. When CVD events were separately evaluated, higher cereal fiber intake was associated with lower risk of total stroke and ischemic stroke and a trend toward lower risk of ischemic heart disease death. In a post hoc analysis, dark breads such as wheat, rye, or pumpernickel were associated with a lower risk of incident CVD (HR, 0.76; 95% CI, 0.64-0.90) rather than cereal fiber from other sources. Cereal fiber consumption late in life is associated with lower risk of incident CVD, supporting recommendations for elderly individuals to increase consumption of dietary cereal fiber.

Inverse association between intake of cereal fiber and risk of gastric cardia cancer

Background & Aims: Recent data show that salivary nitrites form carcinogenic nitrosamines, especially at the gastric cardia. Wheat fiber has been shown to neutralize such mutagen formation. Our aim was to evaluate the association between dietary fiber and cancers of the esophageal and gastric cardia. Methods: We examined data from a large-scale population-based case-control study of risk factors for adenocarcinoma of the gastric cardia and esophagus and squamous cell carcinoma of the esophagus. Results: We found a strong dose-dependent inverse association between total dietary fiber intake and risk of gastric cardia adenocarcinoma, which was driven mainly by intake of cereal fiber. The odds ratio among individuals in the highest quartile of cereal fiber intake compared with the lowest was 0.3 (95% confidence interval, 0.2–0.5; P trend < 0.0001). High intake of cereal fiber was also associated with a moderately decreased risk of esophageal adenocarcinoma, but no linear dose-risk trend was observed. There was no association between dietary fiber and esophageal squamous cell carcinoma. Conclusions: High intake of cereal fiber may significantly lower the risk of gastric cardia cancer.GASTROENTEROLOGY 2001;120:387-391

Diet and cancer mortality in the counties of Sweden.

The association between standardized cancer mortality rate ratios from 1969-1978 and dietary practices was examined in an ecologic study of the 24 counties of Sweden by means of several independent data sources. The study supports the hypothesis that a high intake of cereal fiber protects against colorectal cancer (r = -0.75 for males and r = -0.67 for females). This study found no association between fat intake and colorectal cancer. However, a negative correlation between milk consumption and this type of cancer was found. A suggested hypothesis is that calcium protects against colorectal cancer, since milk is the major source for calcium intake in Sweden. This could indicate that, for societies with a high fat intake, preventive measures which increase the intake of fiber and milk or calcium might have a greater impact on mortality from cancer of the colon and rectum than would a moderate decrease in the intake of fat. There are no indications in this study that fat intake promotes breast cancer.