Dietary Fiber Intake: Assessing the Degree of Agreement between Food Frequency Questionnaires and 4-Day Food Records

Associations of Habitual Dietary Intake With Fecal Short-Chain Fatty Acids and Bowel Functions in Irritable Bowel Syndrome

BACKGROUND GOALS

Diet may contribute to symptoms of irritable bowel syndrome (IBS) and luminal production of putative IBS biomarkers including short-chain fatty acids (SCFAs). Study aims were to to assess relationships of habitual fiber or starch intake with fecal SCFAs in patients with IBS and healthy volunteers (HVs).

STUDY

In 18 HVs and 30 patients with IBS (13 constipation-predominant [IBS-C] and 17 diarrhea-predominant [IBS-D]), habitual diet using a food frequency questionnaire; bowel functions using a validated bowel diary; and fecal SCFAs by HPLC-mass spectrometry were assessed. Associations of fiber and starch with SCFAs were analyzed using Spearman (rs) and Pearson (R) correlations. Relationships between other dietary endpoints, SCFAs, and bowel functions were explored.

RESULTS

Habitual fiber or starch intakes were not significantly correlated with SCFAs or bowel functions in all participants or HVs nor with SCFAs in IBS. Starch was negatively correlated (R=-0.53; P=0.04) with complete evacuation in IBS-D. Fiber (rs=0.65; P=0.02) and starch (rs=0.56; P=0.05) were correlated with ease of passage in IBS-C. Stool form, frequency, and ease of passage were positively correlated with total SCFAs (all P<0.05), acetate (all P<0.01), propionate (all P<0.05), and butyrate (form P=0.01; ease of passage P=0.05) among all participants, but not in IBS. Complete evacuation was negatively correlated with propionate (R=-0.34; P=0.04) in all participants. Total (P=0.04) and individual SCFAs (all P<0.05) were positively correlated with stool form in HVs.

CONCLUSIONS

Habitual fiber and starch intake does not influence fecal SCFAs but may influence bowel functions in IBS. Fecal SCFAs correlate with bowel functions among all participants including HVs.

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.

Probiotics-induced changes in gut microbial composition and its effects on cognitive performance after stress: exploratory analyses

Stress negatively affects cognitive performance. Probiotics remediate somatic and behavioral stress responses, hypothetically by acting on the gut microbiota. Here, in exploratory analyses, we assessed gut microbial alterations after 28-days supplementation of multi-strain probiotics (EcologicBarrier consisting of Lactobacilli, Lactococci, and Bifidobacteria in healthy, female subjects (probiotics group n = 27, placebo group n = 29). In an identical pre-session and post-session, subjects performed a working memory task before and after an acute stress intervention. Global gut microbial beta diversity changed over time, but we were not able to detect differences between intervention groups. At the taxonomic level, Time by Intervention interactions were not significant after multiple comparison correction; the relative abundance of eight genera in the probiotics group was higher (uncorrected) relative to the placebo group: Butyricimonas, Parabacteroides, Alistipes, Christensenellaceae_R-7_group, Family_XIII_AD3011_group, Ruminococcaceae_UCG-003, Ruminococcaceae_UCG-005, and Ruminococcaceae_UCG-010. In a second analysis step, association analyses were done only within this selection of microbial genera, revealing the probiotics-induced change in genus Ruminococcaceae_UCG-003 was significantly associated with probiotics' effect on stress-induced working memory changes (rspearman(27) = 0.565; pFDR = 0.014) in the probiotics group only and independent of potential confounders (i.e., age, BMI, and baseline dietary fiber intake). That is subjects with a higher increase in Ruminococcaceae_UCG-003 abundance after probiotics were also more protected from negative effects of stress on working memory after probiotic supplementation. The bacterial taxa showing an increase in relative abundance in the probiotics group are plant fiber degrading bacteria and produce short-chain fatty acids that are known for their beneficial effect on gut and brain health, e.g., maintaining intestinal-barrier and blood-brain-barrier integrity. This study shows that gut microbial alterations, modulated through probiotics use, are related to improved cognitive performance in acute stress circumstances.

The effectiveness of peer-supported interventions for encouraging dietary behaviour change in adults: a systematic review

OBJECTIVE

There is an urgent need to find effective methods of supporting individuals to make dietary behaviour changes. Peer-supported interventions (PSI) have been suggested as a cost-effective strategy to support chronic disease self-management. However, the effect of PSI on dietary behaviour is unclear. The present systematic review aimed to assess the effectiveness of PSI for encouraging dietary behaviour change in adults and to consider intervention characteristics linked with effectiveness.

DESIGN

Electronic databases were searched until June 2018 for randomised controlled trials assessing the effectiveness of PSI compared with an alternative intervention and/or control on a dietary related outcome in adults. Following title and abstract screening, two reviewers independently screened full texts and data were extracted by one reviewer and independently checked by another. Results were synthesised narratively.

SETTING

Randomised controlled trials.ParticipantsAdult studies.

RESULTS

The fifty-four included studies varied in participants, intervention details and results. More PSI reported a positive or mixed effect on diet than no effect. Most interventions used a group model and were lay-led by peer supporters. Several studies did not report intervention intensity, fidelity and peer training and support in detail. Studies reporting positive effects employed more behaviour change techniques (BCT) than studies reporting no effect; however, heterogeneity between studies was considerable.

CONCLUSIONS

As evidence was mixed, further interventions need to assess the effect of PSI on dietary behaviour, describe intervention content (theoretical basis, BCT, intensity and peer training/support) and include a detailed process evaluation.

Relative validity and reproducibility of a food frequency questionnaire to assess dietary fiber intake in Danish adults

Background

Differences in habitual dietary fiber intake may modify effects of dietary fiber interventions, thus measurement of habitual dietary fiber intake is relevant to apply in intervention studies on fiber-rich foods, and food frequency questionnaire (FFQ) is a commonly used method. Rye bread is the major contributor of dietary fiber in the Danish population, and a nation-specific FFQ is therefore needed.

Objective

The aim of this study was to assess the relative validity and reproducibility of a self-administered quantitative FFQ designed to assess total dietary fiber intake among Danish adults.

Design

In order to assess the relative validity of the FFQ, a total of 125 participants completed both a 7-day weighed dietary recording (DR) and an FFQ consisting of 60 questions. To evaluate the reproducibility of the FFQ, a sub-group of 12 participants subsequently completed an FFQ approximately 6 months later.

Results

Estimates of mean dietary fiber intake were 24.9±9.8 and 28.1±9.4 g/day when applying the FFQ and DR, respectively, where FFQ estimates were ~12% lower (p<0.001). Pearson's correlation coefficient between the estimated dietary fiber intake of the two methods was r=0.63 (p<0.001), and 62% of the participants were grouped into the same tertile of intake according to the two methods. The estimates of mean dietary intake of first and second FFQ were very similar (22.2±4.0 and 23.3±4.1 g/day, respectively, p=0.42) and showed a correlation of r=0.95 (95% CI 0.83–0.99).

Conclusion

The developed FFQ showed moderate underestimation of dietary fiber intake (g/day), adequate ranking of subjects according to their dietary fiber intake, and good reproducibility. The FFQ is therefore believed to be a valuable tool for epidemiology and screening in human interventions, where intake of dietary fibers is of specific interest.

Structural changes in the gut microbiome of constipated patients

Previous studies using culture-based methods suggested an association between constipation and altered abundance of certain taxa of the colonic microbiome. We aim to examine the global changes in gut microbial composition of constipated patients. A cross-sectional pilot study using 16S rRNA gene pyrosequencing was performed to compare stool microbial composition of eight constipated patients and 14 nonconstipated controls. Only obese children were enrolled so that the microbiome features associated with constipation would not be obscured by those associated with obesity. The sequencing reads were processed by QIIME for quantitative analysis of the microbial composition at genus and above levels. Dietary intake for all the individuals was assessed by dietary recalls and a food frequency questionnaire. The ecological diversities of fecal microbiome of the constipated patients differed from those of the controls. Significantly decreased abundance in Prevotella and increased representation in several genera of Firmicutes were observed in constipated patients compared with controls. The conventional probiotic genera Lactobacillus and Bifidobacteria were not decreased in the microbiomes of the constipated patients. These alterations in the fecal microbiome of constipated patients suggested that a novel probiotic treatment including certain Prevotella strains may be more effective than conventional probiotic products incorporating Lactobacillus or Bifidobacterium species. While it is possible that the observed changes in the microbiome in constipated subjects are a consequence of a low-fiber diet, these changes also predict a different pattern of bacterial fermentation end-products, such as increased butyrate production, which may contribute to pathogenesis of constipation.

Effects of regularly consuming dietary fibre rich soluble cocoa products on bowel habits in healthy subjects: a free-living, two-stage, randomized, crossover, single-blind intervention

BACKGROUND

Dietary fibre is both preventive and therapeutic for bowel functional diseases. Soluble cocoa products are good sources of dietary fibre that may be supplemented with this dietary component. This study assessed the effects of regularly consuming two soluble cocoa products (A and B) with different non-starch polysaccharides levels (NSP, 15.1 and 22.0% w/w, respectively) on bowel habits using subjective intestinal function and symptom questionnaires, a daily diary and a faecal marker in healthy individuals.

METHODS

A free-living, two-stage, randomized, crossover, single-blind intervention was carried out in 44 healthy men and women, between 18-55 y old, who had not taken dietary supplements,laxatives, or antibiotics six months before the start of the study. In the four-week-long intervention stages, separated by a three-week-wash-out stage, two servings of A and B, that provided 2.26 vs. 6.60 g/day of NSP respectively, were taken. In each stage, volunteers' diet was recorded using a 72-h food intake report.

RESULTS

Regularly consuming cocoa A and B increased fibre intake, although only cocoa B significantly increased fibre intake (p < 0.001) with respect to the non-cocoa stage. No changes in body weight were observed in either of the 4 week interventions. With cocoa product B, the number of daily bowel movements increased (p = 0.002), the frequency of having a bowel movement once a day increased (p = 0.009), the time to have a bowel movement was lower (p = 0.016) as well as the feeling of constipation (p = 0.046) without inducing adverse gastrointestinal symptoms, only flatulence increased (p = 0.019).

CONCLUSIONS

Regular consumption of the cocoa products increases dietary fibre intake to recommended levels and product B improves bowel habits. The use of both objective and subjective assessments to evaluate the effects of food on bowel habits is recommended.

Nutritional biomarkers and foodomic methodologies for qualitative and quantitative analysis of bioactive ingredients in dietary intervention studies

Traditional dietary assessment methods, such as 24-h recalls, weighted food diaries and food frequency questionnaires (FFQs) are highly subjective and impair the assessment of successfully accomplished dietary interventions. Foodomic technologies offer promising methodologies for gathering scientific evidence from clinical trials with sensitive methods (e.g., GC-MS, LC-MS, CE, NMR) to detect and quantify markers of nutrient exposure or subtle changes in dietary patterns. This review provides a summary of recently developed foodomic methodologies for the detection of suggested biomarkers, including the food specificity for each suggested biomarker and a brief description of the key aspects of 24-h recalls that may affect marker detection and stability, such as mixed nutrients and cooking processes. The primary aim of this review is to contribute to the assessment of the metabolic effects of active ingredients and foods using cutting-edge methods to improve approaches to future nutritional programs tailored for health maintenance and disease prevention.

Constipation and risk of cardiovascular disease among postmenopausal women

BACKGROUND

Constipation is common in Western societies, accounting for 2.5 million physician visits/year in the US. Because many factors predisposing to constipation also are risk factors for cardiovascular disease, we hypothesized that constipation may be associated with increased risk of cardiovascular events.

METHODS

We conducted a secondary analysis in 93,676 women enrolled in the observational arm of the Women's Health Initiative. Constipation was evaluated at baseline by a self-administered questionnaire. Estimates of the risk of cardiovascular events (cumulative end point including mortality from coronary heart disease, myocardial infarction, angina, coronary revascularization, stroke, and transient ischemic attack) were derived from Cox proportional hazards models adjusted for demographics, risk factors, and other clinical variables (median follow-up 6.9 years).

RESULTS

The analysis included 73,047 women. Constipation was associated with increased age, African American and Hispanic descent, smoking, diabetes, high cholesterol, family history of myocardial infarction, hypertension, obesity, lower physical activity levels, lower fiber intake, and depression. Women with moderate and severe constipation experienced more cardiovascular events (14.2 and 19.1 events/1000 person-years, respectively) compared with women with no constipation (9.6/1000 person-years). After adjustment for demographics, risk factors, dietary factors, medications, frailty, and other psychological variables, constipation was no longer associated with an increased risk of cardiovascular events except for the severe constipation group, which had a 23% higher risk of cardiovascular events.

CONCLUSION

In postmenopausal women, constipation is a marker for cardiovascular risk factors and increased cardiovascular risk. Because constipation is easily assessed, it may be a helpful tool to identify women with increased cardiovascular risk.

Contaminated fish consumption in California's Central Valley Delta

Extensive mercury contamination and angler selection of the most contaminated fish species coincide in California's Central Valley. This has led to a policy conundrum: how to balance the economic and cultural impact of advising subsistence anglers to eat less fish with the economic cost of reducing the mercury concentrations in fish? State agencies with regulatory and other jurisdictional authority lack sufficient data and have no consistent approach to this problem. The present study focused on a critical and contentious region in California's Central Valley (the Sacramento-San Joaquin Rivers Delta) where mercury concentrations in fish and subsistence fishing rates are both high. Anglers and community members were surveyed for their fish preferences, rates of consumption, the ways that they receive health information, and basic demographic information. The rates of fish consumption for certain ethnicities were higher than the rates used by state agencies for planning pollution remediation. A broad range of ethnic groups were involved in catching and eating fish. The majority of anglers reported catching fish in order to feed to their families, including children and women of child-bearing age. There were varied preferences for receiving health information and no correlation between knowledge of fish contamination and rates of consumption. Calculated rates of mercury intake by subsistence anglers were well above the EPA reference dose. The findings here support a comprehensive policy strategy of involvement of the diverse communities in decision-making about education and clean-up and an official recognition of subsistence fishers in the region.

The effect of strict adherence to a high-fiber, high-fruit and -vegetable, and low-fat eating pattern on adenoma recurrence

Individual differences in dietary intake are thought to account for substantial variation in cancer incidence. However, there has been a consistent lack of effect for low-fat, high-fiber dietary interventions and risk of colorectal cancer. These inconsistencies may reflect the multistage process of cancer as well as the range and timing of dietary change. Another potential reason for the lack of effect is poor dietary adherence among participants in these trials. The authors examined the effect of strict adherence to a low-fat, high-fiber, high-fruit and -vegetable intervention over 4 years among participants (n = 1,905) in the US Polyp Prevention Trial (1991-1998) on colorectal adenoma recurrence. There was a wide range of individual variation in the level of compliance among intervention participants. The most adherent participants, defined as "super compliers" (n = 210), consistently reported that they met or exceeded each of the 3 dietary goals at all 4 annual visits. Multivariate logistic regression models were used to estimate the association between dietary adherence and adenoma recurrence. The authors observed a 35% reduced odds of adenoma recurrence among super compliers compared with controls (odds ratio = 0.65, 95% confidence interval: 0.47, 0.92). Findings suggest that high compliance with a low-fat, high-fiber diet is associated with reduced risk of adenoma recurrence.

Dietary fiber and associations with adiposity and fasting insulin among college students with plausible dietary reports

OBJECTIVE

We examined dietary fiber intake, food sources of dietary fiber, and relation of dietary fiber to body composition and metabolic parameters in college students with plausible dietary reports.

METHODS

Students (18-24 y of age) provided data on anthropometry, fasting blood chemistries, and body composition (bioelectric impedance). Diet and physical activity were assessed with the Diet History Questionnaire and the International Physical Activity Questionnaire. Plausible dietary reporters were identified (+/-1 SD cutoffs for reported energy intake as a percentage of predicted energy requirement). Multiple regression analyses were conducted with the total (n = 298) and plausible (n = 123) samples, adjusting for age, race, sex, smoking status, physical activity, energy intake, and fat-free mass (where applicable).

RESULTS

Food sources of dietary fiber were similar in men and women. In the plausible sample compared with the total sample, dietary fiber was more strongly associated with fat mass (beta = -0.24, P < 0.001), percentage of body fat (beta = -0.23, P < 0.001), body mass index (beta = -0.11, P < 0.01), waist circumference (beta = -0.67, P < 0.05), and fasting insulin (beta = -0.15, P < 0.001). When the effect of sex was investigated, dietary fiber was inversely related to fasting insulin and fat mass in men and women and inversely related to percentage of body fat, body mass index, and waist circumference in men only (P < 0.05).

CONCLUSION

Inclusion of implausible dietary reports may result in spurious or weakened diet-health associations. Dietary fiber is negatively associated with fasting insulin levels in men and women and consistently associated with adiposity measurements in men.

Finding factors influencing risk: comparing Bayesian stochastic search and standard variable selection methods applied to logistic regression models of cases and controls

When modeling the risk of a disease, the very act of selecting the factors to be included can heavily impact the results. This study compares the performance of several variable selection techniques applied to logistic regression. We performed realistic simulation studies to compare five methods of variable selection: (1) a confidence interval (CI) approach for significant coefficients, (2) backward selection, (3) forward selection, (4) stepwise selection, and (5) Bayesian stochastic search variable selection (SSVS) using both informed and uniformed priors. We defined our simulated diseases mimicking odds ratios for cancer risk found in the literature for environmental factors, such as smoking; dietary risk factors, such as fiber; genetic risk factors, such as XPD; and interactions. We modeled the distribution of our covariates, including correlation, after the reported empirical distributions of these risk factors. We also used a null data set to calibrate the priors of the Bayesian method and evaluate its sensitivity. Of the standard methods (95 per cent CI, backward, forward, and stepwise selection) the CI approach resulted in the highest average per cent of correct associations and the lowest average per cent of incorrect associations. SSVS with an informed prior had a higher average per cent of correct associations and a lower average per cent of incorrect associations than the CI approach. This study shows that the Bayesian methods offer a way to use prior information to both increase power and decrease false-positive results when selecting factors to model complex disease risk.

Poor adherence to dietary guidelines among adult survivors of childhood acute lymphoblastic leukemia

Recent studies indicate that survivors of childhood acute lymphoblastic leukemia (ALL) are at increased risk of obesity and cardiovascular disease, conditions that healthy dietary patterns may help ameliorate or prevent. To evaluate the usual dietary intake of adult survivors of childhood ALL, food frequency questionnaire data were collected from 72 participants, and compared with the 2007 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) Cancer Prevention recommendations, the Dietary Approaches to Stop Hypertension (DASH) diet, and the 2005 United States Department of Agriculture (USDA) Food Guide. Mean daily energy intake was consistent with estimated requirements; however, mean body mass index was 27.1 kg/m2 (overweight). Dietary index scores averaged fewer than half the possible number of points on all 3 scales, indicating poor adherence to recommended guidelines. No study participant reported complete adherence to any set of guidelines. Although half the participants met minimal daily goals for 5 servings of fruits and vegetables (WCRF/AICR recommendations) and Collapse

Key Words Collapse

MESH Headings

• Adult
• Body Mass Index
• Cardiovascular Diseases/prevention & control
• Child
• Diet/standards
• Energy Intake
• Feeding Behavior
• Female
• Guideline Adherence
• Health Status
• Humans
• Male
• Nutrition Policy
• Patient Compliance
• Precursor Cell Lymphoblastic Leukemia-Lymphoma/diet therapy
• Surveys and Questionnaires
• Survivors

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Grants

• M01 RR000400 NCRR NIH HHS
• U24 CA055727 NCI NIH HHS
• M01-RR00400 NCRR NIH HHS
• K23 CA085503 NCI NIH HHS
• R21 CA106778 NCI NIH HHS
• R21-CA106778 NCI NIH HHS
• K23-CA85503 NCI NIH HHS
• U24-CA55727 NCI NIH HHS
• R21 CA106778-02 NCI NIH HHS

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Affiliation(s)

Kim Robien Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, 1300 S. Second St, 300 WBOB, Minneapolis, MN 55454, USA.
Kirsten K Ness
Lisa M Klesges
K Scott Baker
James G Gurney

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Dietary flavonoids and colorectal adenoma recurrence in the Polyp Prevention Trial

Two recent case-control studies suggested that some flavonoid subgroups may play a role in preventing colorectal cancer. Previous prospective cohort studies generally reported no association; however, only a small subset of flavonoids was evaluated and partial flavonoid databases were used. We used the newly constructed U.S. Department of Agriculture flavonoid database to examine the association between consumption of total flavonoids, 6 flavonoid subgroups, and 29 individual flavonoids with adenomatous polyp recurrence in the Polyp Prevention Trial. The Polyp Prevention Trial was a randomized dietary intervention trial, which examined the effectiveness of a low-fat, high-fiber, high-fruit, and high-vegetable diet on adenoma recurrence. Intakes of flavonoids were estimated from a food frequency questionnaire. Multivariate logistic regression models (adjusted for age, body mass index, sex, regular non-steroidal anti-inflammatory use, and dietary fiber intake) were used to estimate odds ratios and 95% confidence intervals for both any and advanced adenoma recurrence within quartiles of energy-adjusted flavonoid intake (baseline, during the trial, and change during the trial). Total flavonoid intake was not associated with any or advanced adenoma recurrence. However, high intake of flavonols, which are at greater concentrations in beans, onions, apples, and tea, was associated with decreased risk of advanced adenoma recurrence (4th versus 1st quartile during the trial; odds ratio, 0.24; 95% confidence interval, 0.11, 0.53; P(trend) = 0.0006). Similar inverse associations were observed to a smaller extent for isoflavonoids, the flavonol kaempferol, and the isoflavonoids genistein and formononetin. Our data suggest that a flavonol-rich diet may decrease the risk of advanced adenoma recurrence.

Adherence to the polyp prevention trial dietary intervention is associated with a behavioral pattern of adherence to nondietary trial requirements and general health recommendations

This study investigated the factors associated with success in meeting the dietary goals of the Polyp Prevention Trial (PPT), a 4-y low-fat, high-fiber, high-fruit/vegetable dietary intervention. The PPT provided a rare opportunity to assess factors in long-term adherence to a dietary pattern that required changes to multiple aspects rather than a single aspect of diet. Demographics, health indicators, and dietary intake were assessed at baseline and annually for 4 y of follow-up. Participants (n=833) received dietary and behavioral counseling to support adherence to trial dietary goals. We assessed the association of baseline variables and trial participation with success in meeting dietary goals. Participant adherence to the intervention goals was significantly associated with never smoking, no history of weight gain, and consumption of less fat and more fiber, fruits, and vegetables at trial baseline. Successful participants were also more educated and married, whereas those with the poorest adherence were older. In addition, successful participants demonstrated greater participation throughout the trial, including attendance at counseling sessions, completion of dietary records, and contacts with staff. Of particular interest were the behavioral and demographic characteristics that distinguished the subset of participants who achieved most or all dietary intervention goals across all 4 study years who we termed Super Compliers. These individuals also were more likely to adhere to social norms for healthy lifestyles and demonstrated greater adherence to other aspects of trial participation.