Development, validation and reproducibility of a food frequency questionnaire to measure flavonoid intake in older Australian adults

[Design and validation of a self-reported dietary polyphenol intake frequency questionnaire.]

Introduction

Introduction: although there is evidence linking polyphenol consumption with better health outcomes, information on consumption patterns, particularly in Latin American countries, is scarce. Objective: to design and evaluate the validity of an online self-reported food frequency questionnaire to measure dietary total polyphenol intake in the Chilean adult population. Methods: the designed questionnaire (FFQ-P) was submitted to expert opinion for content validity coefficient estimation; then a pilot study was conducted in 47 adults who completed FFQ-P, in addition to a six-day food record as a reference method. Wilcoxon was applied in related samples, Spearman's correlation to determine the strength of association and Bland-Altman diagrams to examine the difference between methods. Results: content validity reflected concordant values for adequacy (0.94 ± 0.04) and relevance (0.93 ± 0.05). The percentage difference between both methods was 1.2 %, with greater variability observed in fruits (9 %) and alcoholic beverages (4 %). The Wilcoxon test showed no significant differences between food groups. Medium reliability was observed for vegetables, fruits, tea, and coffee (0.26 to 0.5) and moderate reliability for alcoholic beverages (0.5 to 0.75). The mean value of the difference was 9.8, being within a short distance of zero. Conclusion: FFQ-P is reliable for estimating polyphenol intake from fruits, vegetables, alcoholic beverages, tea, and coffee; however, the intake of non-alcoholic beverages, nuts and olives should be interpreted with reservation.

Comparison between dietary assessment methods and biomarkers in estimating dietary (poly)phenol intake

Background: although widely used, there is limited understanding of the suitability of different dietary assessment tools to estimate (poly)phenol intake. This study aims to compare the agreement between a food frequency questionnaire (FFQ) and a 7-day food diary (7DD) in assessing (poly)phenol intake and explore their associations with the urinary and plasma (poly)phenol metabolites. Methods: healthy free-living participants aged 18-80 years (n = 413) completed a 7DD and an FFQ (EPIC-Norfolk) and provided a 24 h urine and a fasting plasma sample. A comprehensive in-house (poly)phenol database was used to estimate (poly)phenol intake. The phenolic metabolite levels were analysed using a validated LC-MS method. The agreement between dietary assessment methods and biomarkers were evaluated by intraclass correlation coefficients (ICC), weighted kappa, quartile classification, Bland-Altman plots and correlations. Results: the total (poly)phenol intake estimated from FFQ was higher than from 7DD (median 1463 and 1042 mg d^-1, respectively). The agreement between FFQ and 7DD were moderate (ICC 0.51-0.59) for total (poly)phenols, flavan-3-ols, total phenolic acids, hydroxycinnamic acids and alkylmethoxyphenols, and were poor for all the other classes and subclasses (ICC 0.00-0.48). Positive correlations with total urine phenolic metabolites were found in FFQ estimated anthocyanins, dihydroflavonols, total lignans, tyrosols, alkylmethoxyphenols, total phenolic acids, and total stilbenes and the 7DD estimated theaflavins and thearubigins (all FDR adjusted p values < 0.1). No significant correlations were found between total plasma phenolic metabolites and (poly)phenol intake. Conclusion: agreements between dietary assessment tools were moderate for the major classes of (poly)phenols, while agreements between (poly)phenol intake and biomarkers were poor. Future research using biomarker approaches to increase the accuracy of estimating (poly)phenol exposure in larger populations is needed.

Reliability and Validity of Simple Stroke Food Frequency Questionnaire (SS-FFQ) for Nutrition Monitoring in Patients with Acute Ischemic Stroke

Objectives  Standard dietary questionnaires may have some limitations in cases with stroke, particularly in those suffering from language and communication difficulties. The present study aimed to develop a dietary questionnaire appropriate for patients with acute ischemic stroke (AIS).

Materials and Methods  Major food groups ( n = 19) were first identified using the dietary questionnaire of the INTERHEART study. Using the Food Frequency Questionnaire (FFQ), an expert dietitian and a vascular neurologist then selected a total number of 68 corresponding food items from 168 available FFQ items. In the next phase, a panel of expert dietitians ( n = 10) assessed the face validity and the content validity of these 68 items and approved a total number of 62 items for the final questionnaire, namely, the Simple Stroke FFQ (SS-FFQ). Employing test-retest method, the intraclass correlation (ICC) of the SS-FFQ was subsequently calculated in 30 randomly selected cases affected with AIS. Ultimately, principal component analysis (PCA) was utilized for 153 cases with AIS to assess the construct validity of the questionnaire concerned. The SPSS Statistics software (version 18: SPSS Inc., Chicago, Illinois, United States) as well as descriptive tests including mean and percentage were additionally used to account for the baseline characteristics of the study participants.

Results  The results revealed that the reliability of the newly developed form of the SS-FFQ was perfect (ICC = 0.86). Dietary conditions were further assessed administering the SS-FFQ on 153 cases of AIS with the mean age of 63.76 ± 15.93 years. The PCA results also showed that 15 extracted items of the given questionnaire could explain 73.10% of total item variance.

Conclusions  It was concluded that the SS-FFQ was a valid and reliable questionnaire to assess nutrient intakes among patients with AIS.

An overview and update on the epidemiology of flavonoid intake and cardiovascular disease risk

There is an accumulating body of literature reporting on dietary flavonoid intake and the risk of cardiovascular disease (CVD) in prospective cohort studies. This makes apparent the need for an overview and update on the current state of the science. To date, at least 27 prospective cohorts (in 44 publications) have evaluated the association between estimated habitual flavonoid intake and CVD risk. At this time, the totality of evidence suggests long-term consumption of flavonoid-rich foods may be associated with a lower risk of fatal and non-fatal ischemic heart disease (IHD), cerebrovascular disease, and total CVD; disease outcomes which are principally, though not exclusively, composed of cases of atherosclerotic CVD (ASCVD). To date, few studies have investigated outcome specific ASCVD, such as peripheral artery disease (PAD) or ischemic stroke. Of the flavonoid subclasses investigated, evidence more often implicates diets rich in anthocyanins, flavan-3-ols, and flavonols in lowering the risk of CVD. Although inferences are restricted by confounding and other inherent limitations of observational studies, causality appears possible based on biological plausibility, temporality, and the relative consistency of the reported associations. However, whether the associations observed represent a benefit of the isolated bioactives per se, or are a signal of the bioactives acting in concert with the co-occurring nutrient matrix within flavonoid-bearing foods, are issues of consideration. Thus, the simple interpretation, and the one most relevant for dietary advice, is that consumption of flavonoid-rich foods or diets higher in flavonoids, appear nutritionally beneficial in the prevention of CVD.

Dietary flavonoids and flavonoid-rich foods: validity and reproducibility of FFQ-derived intake estimates

OBJECTIVE

To evaluate the validity and reproducibility of a 152-item semi-quantitative FFQ (SFFQ) for estimating flavonoid intakes.

DESIGN

Over a 1-year period, participants completed two SFFQ and two weighed 7-d dietary records (7DDR). Flavonoid intakes from the SFFQ were estimated separately using Harvard (SFFQHarvard) and Phenol-Explorer (SFFQPE) food composition databases. 7DDR flavonoid intakes were derived using the Phenol-Explorer database (7DDRPE). Validity was assessed using Spearman's rank correlation coefficients deattenuated for random measurement error (rs), and reproducibility was assessed using rank intraclass correlation coefficients.

SETTING

This validation study included primarily participants from two large observational cohort studies.

PARTICIPANTS

Six hundred forty-one men and 724 women.

RESULTS

When compared with two 7DDRPE, the validity of total flavonoid intake assessed by SFFQPE was high for both men and women (rs = 0·77 and rs = 0·74, respectively). The rs for flavonoid subclasses ranged from 0·47 for flavones to 0·78 for anthocyanins in men and from 0·46 for flavonols to 0·77 for anthocyanins in women. We observed similarly moderate (0·4-0·7) to high (≥0·7) validity when using SFFQHarvard estimates, except for flavonesHarvard (rs = 0·25 for men and rs = 0·19 for women). The SFFQ demonstrated high reproducibility for total flavonoid and flavonoid subclass intake estimates when using either food composition database. The intraclass correlation coefficients ranged from 0·69 (flavonolsPE) to 0·80 (proanthocyanidinsPE) in men and from 0·67 (flavonolsPE) to 0·77 (flavan-3-ol monomersHarvard) in women.

CONCLUSIONS

SFFQ-derived intakes of total flavonoids and flavonoid subclasses (except for flavones) are valid and reproducible for both men and women.

Estimated intake and major food sources of flavonoids among Australian adolescents

PURPOSE

The consumption of dietary flavonoids from plant-based foods has been related to the prevention of multiple chronic diseases. However, intake data from adolescents are lacking. We aimed to characterise the intake and major sources of dietary flavonoids among Australian adolescents and investigate changes during adolescence.

METHODS

The Raine Study Gen 2 participants completed a 212-item food frequency questionnaire at age 14 years and 17 years, with repeated measures for n = 883. Items were assigned a content for six flavonoid subclasses using the Phenol-Explorer database, which were summed for total flavonoid intake. Daily intakes and sources of flavonoids and flavonoid-subclasses were determined, and change assessed between 14 and 17 years, for males and females.

RESULTS

Major food sources of flavonoids and each subclass were similar at 14 and 17 years, with fruit juice the major contributor to total flavonoid intake at both time points (providing 44% and 38%, respectively). Citrus flavanones (predominantly hesperitin) were the major subclass at 14 years, while tea flavan-3-ols were a major subclass (predominantly procyanidin dimers) at 17 years. The mean intake of total flavonoids at 14 years was 210 ± 133 mg/day, reducing by 5% (10 mg/day) by 17 years. Females consumed a more flavonoid-dense diet compared to males (104.5 ± 71.5 mg/1000 kcal vs 80.4 ± 50.3 mg/1000 kcal per day; p < 0.001).

CONCLUSION

This study provides a comprehensive estimation of flavonoid intake and their major food sources in a sample of Australian adolescents, which may be useful in the development of practical dietary recommendations.

Iron intake is positively associated with viral load in antiretroviral naïve Brazilian men living with HIV

BACKGROUND

Iron homeostasis contribute for the human immunodeficiency virus (HIV) pathogenesis.

OBJECTIVES

We assessed the iron intake pattern in antiretroviral naïve Brazilian men living with HIV correlating with clinical and nutritional parameters.

METHODS

The iron consumption mean was estimated according to a food frequency questionnaire (FFQ), and a 3-day food record (3dFR) submitted to the patients. HIV viral load, CD4+ T cell counts, serum iron, haematological and anthropometrics parameters were recorded.

FINDINGS

Fifty-one HIV-infected adult men naïve for antiretroviral therapy (ART) were enrolled. The mean age of participants was 35 (SEM ± 1.28) years old, with mean time of HIV-1 infection of 1.78 (0-16.36, min-max) years. Majority (41.18%) had complete secondary, and 21.57% had tertiary educational level. The income was around 1x (54.90%) to 2x (41.18%) minimum wage. Fifty-four percent showed normal weight, while 40% were overweight. The patients showed normal mean values of haematological parameters, and mean serum iron was 14.40 µM (SEM ± 0.83). The FFQ showed moderate correlation with the 3dFR (ρ = 0.5436, p = 0.0009), and the mean values of iron intake were 10.55(± 0.92) mg/day, recorded by FFQ, and 15.75(± 1.51) mg/day, recorded by 3dFR. The iron intake, recorded by FFQ, negatively correlated with serum iron (ρ = -0.3448, p = 0.0132), and did not have influence in the CD4+ T cell counts [e.B 0.99 (0.97-1.01, 95% confidence interval (CI), p = 0.2]. However, the iron intake showed a positive effect in HIV viral load [e.B 1.12 (1.02-1.25, 95%CI), p < 0.01].

MAIN CONCLUSIONS

This study draws attention for the importance of iron intake nutritional counseling in people living with HIV. However, more studies are required to clarify the association between high iron intake and HIV infection and outcome.

Dietary flavonoid intake in older adults: how many days of dietary assessment are required and what is the impact of seasonality?

BACKGROUND

Within- and between-person variation in nutrient intake is well established, but little is known about variability in dietary flavonoid intake, including the effect of seasonality.

METHODS

Within- and between-individual variability of flavonoid intake, and intake of flavonoid subclasses was examined in older adults (n = 79; mean age 70.1 y (range: 60y-80y)), using three separate 4-day weighed food records (WFR) collected approximately 4 months apart. The effects of seasonality were also examined. Mixed-effects linear regression models were used to estimate within- and between-individual variance components for flavonoids and subclasses. The number of days of dietary assessment required for a high level of hypothetical accuracy was calculated from variance ratios.

RESULTS

Within- and between-individual variability was high for flavonoid intake, and intake of flavonoid subclasses, with variance ratios > 1. It was calculated that six days of WFR data are required for total flavonoid intake, and between 6 and 10 days was required for flavonoid subclasses. There was no effect of seasonality for total flavonoid intake or intake of flavonoid subclasses, with the exception that flavan-3-ol and flavanone intakes which were relatively low in summer, and in summer and winter, respectively.

CONCLUSION

While the effects of seasonality on total flavonoid intake may be small, within- and between-individual variation associated with flavonoid intake assessment appears to be substantial across 12 days of WFR data in older adults. It is recommended that a minimum of 6 days of weighed food records are collected to minimise the impact of within- and between-individual variability on total flavonoid intake assessments in this population.