Evaluating the quality of dietary intake validation studies

Validation of repeated self-reported n-3 PUFA intake using serum phospholipid fatty acids as a biomarker in breast cancer patients during treatment

Background

The role of n-3 polyunsaturated fatty acids (PUFAs) in breast cancer is not clear and under debate. To explore this relationship it is important to have proper validated dietary assessment methods for measuring the intake of n-3 PUFAs. The aim of the current study is to validate two different methods used to assess the intake of selected n-3 PUFAs as well as food sources of long-chained n-3 PUFAs. Also, we aim to study how stable the intake of fatty acids is during breast cancer treatment.

Methods

The study-population was patients with breast cancer (Stages I-II) or ductal carcinoma in situ (DCIS-grade III) undergoing treatment (n = 49) in Norway. Dietary intake was assessed by two self-administered methods, a 256 food item food frequency questionnaire (FFQ) and a 7-day pre-coded food diary (PFD). The FFQ was administered presurgery and twelve months postsurgery, and the PFD was administered shortly after surgery (10 +/− 2 days), six and twelve months postsurgery. Fasting blood samples (presurgery, six and twelve months postsurgery) were analysed for serum phospholipid fatty acids, a biomarker for intake of n-3 PUFAs.

Results

Mean (SD) age was 54.2 (7.8) years at diagnosis, and the mean (SD) body mass index (BMI) was 24.8 (3.4) kg/m². Correlation coefficients between dietary intakes of n-3 PUFAs measured with the FFQ and the PFD ranged from 0.35 to 0.66. The correlation coefficients between the PFD and the biomarker (serum phospholipid n-3 PUFAs) as well as between the FFQ and the biomarker demonstrated stronger correlations twelve months after surgery (ρ 0.40–0.56 and 0.36–0.53, respectively) compared to around surgery (ρ 0.08–0.20 and 0.28–0.38, respectively). The same pattern was observed for intake of fatty fish. The intake of n-3 PUFAs did not change during treatment assessed by the FFQ, PFD or biomarker.

Conclusion

These results indicate that the FFQ and the PFD can be used to assess dietary intake of fish and n-3 PUFAs in breast cancer patients during breast cancer treatment. Still, the PFD shortly after surgery should be used with caution. The diet of patients undergoing breast cancer treatment was quite stable, and the intake of n-3 PUFAs did not change.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0402-6) contains supplementary material, which is available to authorized users.

Development and evaluation of a food frequency questionnaire to assess nutrient intakes of adult women in New Zealand

AIM

In New Zealand, there are few adequate food frequency questionnaires for assessing dietary intake. This study aimed to develop and assess the relative validity of a multi-nutrient, culturally appropriate, semi-quantitative food frequency questionnaire for use in young adult New Zealand women (the New Zealand Women's Food Frequency Questionnaire (NZWFFQ)).

METHODS

Women (n = 110) aged 16-45 years of Māori, Pacific or European ethnicity completed a NZWFFQ assessing dietary intake over the previous month, and a 4-day weighed food record. Relative validity was evaluated by comparing nutrient intakes from the NZWFFQ with the food record using Spearman's rank correlation coefficients, cross-classification, the weighted kappa statistic and Bland-Altman analysis.

RESULTS

Nutrient intake was higher from the NZWFFQ compared with the food record for all nutrients (range: 1%-64% difference) except alcohol (-16% difference). Energy-adjusted correlations ranged from 0.23 to 0.67 (average 0.48). Correct classification into same and adjacent quartiles was over 70% for all nutrients except folate and vitamin D. Gross misclassification into opposite quartiles ranged from 1% (monounsaturated fat, magnesium, calcium) to 10% (iron). The weighted kappa showed poor agreement for vitamin D and folate, fair agreement for most nutrients, and moderate agreement for fibre, vitamin E, magnesium, calcium and phosphorus.

CONCLUSIONS

The NZWFFQ overestimated intake of nearly all nutrients. While not suitable for assessing absolute intake, the NZWFFQ is suitable for ranking individuals based on nutrient intake demonstrating reasonable relative validity for this purpose.

Validation of the Brazilian Healthy Eating Index-Revised Using Biomarkers in Children and Adolescents

The Brazilian Healthy Eating Index-Revised (BHEI-R) can be used to determine overall dietary patterns. We assessed the BHEI-R scores in children and adolescents, aged from 9 to 13 years old, and associated its component scores with biomarkers of health and dietary exposure. Three 24-h recalls were used to generate BHEI-R. Biomarkers were analyzed in plasma and red blood cells. Correlation tests, agreement, and covariance analyses were used to associate BHEI-R components with biomarkers. Data from 167 subjects were used. The strongest correlations were between fruits, vegetables and legumes with omega-6 and omega-3 fatty acids, and β-carotene intakes. Milk and dairy correlated with plasma retinol and pyridoxine. All components rich in vegetable and animal protein sources correlated with plasma creatine. Total BHEI-R scores were positively associated with intakes of omega-6, omega-3, fiber and vitamin C, and inversely associated with energy and saturated fat intakes of individuals. Plasma β-carotene and riboflavin biomarkers were positively associated with total BHEI-R. An inadequate food consumption pattern was captured by both biomarkers of health and dietary exposure. BHEI-R was validated for the above dietary components and can be associated with metabolomics and nutritional epidemiological data in future pediatric studies.

Validity of Dietary Assessment in Athletes: A Systematic Review

Dietary assessment methods that are recognized as appropriate for the general population are usually applied in a similar manner to athletes, despite the knowledge that sport-specific factors can complicate assessment and impact accuracy in unique ways. As dietary assessment methods are used extensively within the field of sports nutrition, there is concern the validity of methodologies have not undergone more rigorous evaluation in this unique population sub-group. The purpose of this systematic review was to compare two or more methods of dietary assessment, including dietary intake measured against biomarkers or reference measures of energy expenditure, in athletes. Six electronic databases were searched for English-language, full-text articles published from January 1980 until June 2016. The search strategy combined the following keywords: diet, nutrition assessment, athlete, and validity; where the following outcomes are reported but not limited to: energy intake, macro and/or micronutrient intake, food intake, nutritional adequacy, diet quality, or nutritional status. Meta-analysis was performed on studies with sufficient methodological similarity, with between-group standardized mean differences (or effect size) and 95% confidence intervals (CI) being calculated. Of the 1624 studies identified, 18 were eligible for inclusion. Studies comparing self-reported energy intake (EI) to energy expenditure assessed via doubly labelled water were grouped for comparison (n = 11) and demonstrated mean EI was under-estimated by 19% (-2793 ± 1134 kJ/day). Meta-analysis revealed a large pooled effect size of -1.006 (95% CI: -1.3 to -0.7; p < 0.001). The remaining studies (n = 7) compared a new dietary tool or instrument to a reference method(s) (e.g., food record, 24-h dietary recall, biomarker) as part of a validation study. This systematic review revealed there are limited robust studies evaluating dietary assessment methods in athletes. Existing literature demonstrates the substantial variability between methods, with under- and misreporting of intake being frequently observed. There is a clear need for careful validation of dietary assessment methods, including emerging technical innovations, among athlete populations.

DIET@NET: Best Practice Guidelines for dietary assessment in health research

BACKGROUND

Dietary assessment is complex, and strategies to select the most appropriate dietary assessment tool (DAT) in epidemiological research are needed. The DIETary Assessment Tool NETwork (DIET@NET) aimed to establish expert consensus on Best Practice Guidelines (BPGs) for dietary assessment using self-report.

METHODS

The BPGs were developed using the Delphi technique. Two Delphi rounds were conducted. A total of 131 experts were invited, and of these 65 accepted, with 48 completing Delphi round I and 51 completing Delphi round II. In all, a total of 57 experts from North America, Europe, Asia and Australia commented on the 47 suggested guidelines.

RESULTS

Forty-three guidelines were generated, grouped into the following four stages: Stage I. Define what is to be measured in terms of dietary intake (what? who? and when?); Stage II. Investigate different types of DATs; Stage III. Evaluate existing tools to select the most appropriate DAT by evaluating published validation studies; Stage IV. Think through the implementation of the chosen DAT and consider sources of potential biases.

CONCLUSIONS

The Delphi technique consolidated expert views on best practice in assessing dietary intake. The BPGs provide a valuable guide for health researchers to choose the most appropriate dietary assessment method for their studies. These guidelines will be accessible through the Nutritools website, www.nutritools.org .

Validation of 'POIBA-How do we eat?' questionnaire in 9-10 years old schoolchildren

Background: It is difficult to obtain good food reports with Food Frequency Questionnaires (FFQ) among children. In addition, validated questionnaires are scarce. Objective: The aim of this study was to validate the 'POIBA-How do we eat?' (POIBA-HDWE) FFQ and whether it could be administered to children under 10 years of age. Design: We validated the FFQ POIBA-HDWE as part of the Childhood Obesity Prevention Program (POIBA project) in Barcelona. Forty-two out of 63 primary school students (9-10 years old) answered three questionnaires: FFQ POBA-HDWE; another questionnaire, 'POIBA-How do our children eat?' (POIBA-HDOCE), which was administered to the children's parents; and the 24-h recall computer program 'Young Adolescents' Nutrition Assessment on Computer' (YANA-C), which was used on three different days as a gold standard. We tested for correlations using the Spearman test for non-parametric variables. Results: We found low compliance with food recommendations (<50%). The POIBA-HDWE and POIBA-HDOCE questionnaires showed a moderate correlation for soft drinks (r = 0.49; p < 0.01), nuts (r = 0.59; p < 0.01), dairy products (r = 0.41; p < 0.01) and juices (r = 0.49; p < 0.01). There were moderate correlations between POIBA-HDWE and YANA-C for fried potatoes (r = 0.42; p = 0.01), dairy products (r = 0.53; p < 0.01), juices (r = 0.41; p < 0.01), and grains(r = 0.50; p < 0.01). Food frequency questions showed a homogeneity of 0.69, and a sensitivity of over 60% for all food items except chips (37.5%) and sweets (51.7%). Conclusions: The POIBA-HDWE FFQ showed moderate correlations with the gold standard, high sensitivity for most food types and acceptable internal consistency. It is an easy and affordable tool for recording food frequency in children under 10 years old.

Perspective: An Extension of the STROBE Statement for Observational Studies in Nutritional Epidemiology (STROBE-nut): Explanation and Elaboration

Nutritional epidemiology is an inherently complex and multifaceted research area. Dietary intake is a complex exposure and is challenging to describe and assess, and links between diet, health, and disease are difficult to ascertain. Consequently, adequate reporting is necessary to facilitate comprehension, interpretation, and generalizability of results and conclusions. The STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) statement is an international and collaborative initiative aiming to enhance the quality of reporting of observational studies. We previously presented a checklist of 24 reporting recommendations for the field of nutritional epidemiology, called "the STROBE-nut." The STROBE-nut is an extension of the general STROBE statement, intended to complement the STROBE recommendations to improve and standardize the reporting in nutritional epidemiology. The aim of the present article is to explain the rationale for, and elaborate on, the STROBE-nut recommendations to enhance the clarity and to facilitate the understanding of the guidelines. Examples from the published literature are used as illustrations, and references are provided for further reading.

Validation of energy intake from a web-based food recall for children and adolescents

The purpose of this study was to validate estimated energy intake from a web-based food recall, designed for children and adolescents. We directly compared energy intake to estimates of total energy expenditure, calculated from accelerometer outputs, combined with data on weight and sex or resting energy expenditure prediction equations. Children (8–9 years) and adolescents (12–14 years) were recruited through schools in Norway in 2013 (N = 253). Results showed that more than one third (36–37%) were identified as under-reporters of energy. In contrast, only 2–4% were defined as over-reporters of energy. The mean energy intake was under-reported with -1.83 MJ/day for the entire study sample. Increased underestimation was observed for overweight and obese participants, the oldest age group (12–14 years), boys, those with parents/legal guardians with low educational level and those living in non-traditional families. In conclusion, energy intake from the web-based food recall is significantly underestimated compared with total energy expenditure, and should be used with caution in young people.

Quality of food-frequency questionnaire validation studies in the dietary assessment of children aged 12 to 36 months: a systematic literature review

A child's diet is an important determinant of growth and development. Because of this, the accurate assessment of dietary intake in young children remains a challenge. A systematic search of studies validating FFQ methodologies in children 12 to 36 months of age was completed. English-language articles published until March 2016 were searched using three electronic databases (MEDLINE, EMBASE and CINAHL). Quality assessment of the identified studies was carried out using The Reduced Summary Score and EURopean micronutrient RECommendations Aligned (EURRECA) scoring system. Seventeen studies were included and categorised according to whether they reflected long-term (≥7 d) or short-term (<7 d) intake, or used a biomarker. A total score for each micronutrient was calculated from the mean of the correlation coefficients weighted by the study quality score. At least three validation studies per micronutrient were required for inclusion. Fifteen studies (83 %) that considered validity of the FFQ in assessing nutrient intakes had quality scores from 2·5 to 6·0. Of those, ten (67 %) studies found FFQ to have good correlations in assessing dietary intake (>0·4). Of the nutrients with three or more studies available, FFQ validated using a reference method reflecting short-term intake had a good weighted correlation for Ca (0·51), and acceptable weighted correlations for vitamin C (0·31) and Fe (0·33). Semi-quantitative FFQ were shown to be valid and reproducible when estimating dietary intakes at a group level, and are an acceptable instruments for estimating intakes of Ca, vitamin C and Fe in children 12 to 36 months of age.

Validation of a newly automated web-based 24-hour dietary recall using fully controlled feeding studies

Background

Assessment of food intake is a cornerstone of nutritional research. However, the use of minimally validated dietary assessment methods is common and can generate misleading results. Thus, there is a need for valid, precise and cost-effective dietary assessment tools to be used in large cohort studies.The objective is to validate a newly developed automated self-administered web-based 24-h dietary recall (R24W), within a population of adults taking part in fully controlled feeding studies.

Methods

Sixty two adults completed the R24W twice while being fed by our research team. Actual intakes were precisely known, thereby allowing the analysis of the proportion of adequately self-reported items. Association between offered and reported portion sizes was assessed with correlation coefficients and agreement with the kappa score while systematics biases were illustrated with Bland-Altman Plot.

Results

Participants received an average of 16 food items per testing day. They reported 89.3% of the items they received. The more frequently omitted food categories were vegetables included in recipes (40.0%) as well as side vegetables (20.0%) and represented less than 5% of the actual daily energy intake. Offered and self-reported portion sizes were significantly correlated (r = 0.80 P < 0.001) and demonstrated a strong agreement as assessed by the kappa score of 0.62. Reported portion sizes for individual food items were on average 3.2 g over the offered portion sizes. Portions of 100 g and above were on average underestimated by 2.4% (r = 0.68 P < 0.01; kappa score = 0.50) while small portions (less than 100 g) were overestimated by 17.1% (r = 0.46 P < 0.01; kappa score = 0.43). A nonsignificant underestimation (-13.9 kcal ± 646.3 kcal; P = 0.83) of energy intake was noted.

Conclusion

R24W performed well as participants were able to report the great majority of items they ate and selected portion size strongly related to the one they received. This suggests that food items are easily to find within the R24W and images of portion sizes used in this dietary assessment tool are adequate and can provide valid food intake evaluation.

Evaluation of a smartphone food diary application using objectively measured energy expenditure

BACKGROUND

Dietary assessment methods are limited in their ability to adequately measure food and beverage consumption. Smartphone applications may provide a novel method of dietary assessment to capture real-time food intake and the contextual factors surrounding eating occasions. The aim of this study is to evaluate the capability of a Smartphone meal diary app ("FoodNow") to measure food intake using a validated objective method for assessing energy expenditure among young adults.

METHODS

Participants (18-30 years) used FoodNow over four non-consecutive days recording all eating occasions through a combination of written text, and/or optional images and voice recordings. A series of contextual questions were also completed. Participants wore the validated SenseWear Armband (BodyMedia Inc, USA) during the same period to measure free-living energy expenditure. Intra-class correlation coefficients (ICC) estimated the reliability of FoodNow to measure estimated energy intake compared to measured energy expenditure.

RESULTS

Ninety participants (71 female, 19 male; mean age = 24.9 ± 4.1 years) were recruited to use the FoodNow app to record their eating occasions. Thirteen were excluded as they did not meet minimum requirements for number of reporting days (n = 3) or SenseWear Armband wear time (5 days of 11 h), while 21 participants were excluded after being identified as mis-reporters (Huang method). Among the remaining sample (n = 56), reliability between estimated energy intake and measured energy expenditure was high (ICC, 95% CI: 0.75, 0.61-0.84).

CONCLUSIONS

FoodNow is a suitable method for capturing estimated energy intake data from young adults. Despite wide levels of agreement at the individual level (-3709 kJ to 2056 kJ), at the group level, FoodNow appears to have potential as a dietary assessment tool. This new dietary assessment method will offer an alternative and novel method of dietary assessment which is capable of collecting both estimated energy intake and contextual factors surrounding eating occasions. Information collected may be used to inform future public health messages or research interventions.

Measurement of availability and accessibility of food among youth: a systematic review of methodological studies

Background

Comprehensive and psychometrically tested measures of availability and accessibility of food are needed in order to explore availability and accessibility as determinants and predictors of dietary behaviors. The main aim of this systematic review was to update the evidence regarding the psychometric properties of measures of food availability and accessibility among youth. A secondary objective was to assess how availability and accessibility were conceptualized in the included studies.

Methods

A systematic literature search was conducted using Medline, Embase, PsycINFO and Web of Science. Methodological studies published between January 2010 and March 2016 and reporting on at least one psychometric property of a measure of availability and/or accessibility of food among youth were included. Two reviewers independently extracted data and assessed study quality. Existing criteria were used to interpret reliability and validity parameters.

Results

A total of 20 studies were included. While 16 studies included measures of food availability, three included measures of both availability and accessibility; one study included a measure of accessibility only. Different conceptualizations of availability and accessibility were used across the studies. The measures aimed at assessing availability and/or accessibility in the home environment (n = 11), the school (n = 4), stores (n = 3), childcare/early care and education services (n = 2) and restaurants (n = 1). Most studies followed systematic steps in the development of the measures. The most common psychometrics tested for these measures were test-retest reliability and criterion validity. The majority of the measures had satisfactory evidence of reliability and/or validity. None of the included studies assessed the responsiveness of the measures.

Conclusions

The review identified several measures of food availability or accessibility among youth with satisfactory evidence of reliability and/or validity. Findings indicate a need for more studies including measures of accessibility and addressing its conceptualization. More testing of some of the identified measures in different population groups is also warranted, as is the development of more measures of food availability and accessibility in the broader environment such as the neighborhood food environment.

Validity of the Food Frequency Questionnaire Assessing the Folate Intake in Women of Reproductive Age Living in a Country without Food Fortification: Application of the Method of Triads

The study aimed to examine the external validity of the Folate Food Frequency Questionnaire (F-FFQ) designed for assessing the folate intake in Serbian women of reproductive age. The F-FFQ was tested against repeated 24 h dietary recalls and correspondent nutritional biomarkers (red blood cells (RBC) and serum folate concentrations) using the method of triads. In a cross sectional study, 503 women aged 18-49 years completed dietary questionnaires and representative validation subsample (n = 50) provided fasting blood samples for biomarker analyses. Correlation coefficients were calculated between each of the dietary methods and three pair-wise correlations were applied for the calculation of validity coefficients. Correlation coefficients observed between F-FFQ and three 24 h recalls were r = 0.56 (p < 0.001) and r = 0.57 (p < 0.001) for total sample and validation group, respectively. Bland-Altman plot and cross-classification analyses indicated good agreement between methods. High validity coefficients were determined between the true intake (I) and dietary assessment methods, F-FFQ (Q) and 24 h dietary recalls (R) (ρQIrbc = 0.871 and ρQIser = 0.814; ρRIrbc = 0.652 and ρRIser = 0.698), and moderate ones for biomarkers (B) (ρBIrbc = 0.428 and ρBIser = 0.421). The F-FFQ is valid instrument for the assessment of dietary folate intake in women living in Serbia, a country without mandatory folic acid food fortification.

Development and Validation of a Photographic Method to Use for Dietary Assessment in School Settings

OBJECTIVE

To develop and validate a photographic method aimed at making assessment of dietary intake in school canteens non-obstrusive, practical and feasible.

METHODS

The study was conducted in two elementary schools representing two different school canteen systems; main dish being served by canteen staff (Iceland), and complete self-serving (Sweden). Food items in serving and leftovers were weighed and photographed. Trained researchers estimated weights of food items by viewing the photographs and comparing them with pictures of half and full reference portions with known weights. Plates of servings and leftovers from 48 children during five school days (n = 448 plates) and a total of 5967 food items were estimated. The researchers' estimates were then compared with the true weight of the foods and the energy content calculated.

RESULTS

Weighed and estimated amounts correlated across meals both in grams and as total energy (0.853-0.977, p<0.001). The agreement between estimated energy content in school meals was close to the true measurement from weighed records; on average 4-19 kcal below true values. Organisation of meal service impacted the efficacy of the method as seen in the difference between countries; with Iceland (served by canteen staff) having higher rate of acceptable estimates than Sweden (self-serving), being 95% vs 73% for total amount (g) in serving. Iceland more often had serving size between or above the half and full reference plates compared with Sweden.

CONCLUSIONS

The photographic method provides acceptable estimates of food and energy intake in school canteens. However, greater accuracy can be expected when foods are served by canteen staff compared with self-serving.

A systematic review of methods to assess intake of fruits and vegetables among healthy European adults and children: a DEDIPAC (DEterminants of DIet and Physical Activity) study

Objective

Evidence suggests that health benefits are associated with consuming recommended amounts of fruits and vegetables (F&V), yet standardised assessment methods to measure F&V intake are lacking. The current review aims to identify methods to assess F&V intake among children and adults in pan-European studies and inform the development of the DEDIPAC (DEterminants of DIet and Physical Activity) toolbox of methods suitable for use in future European studies.

Design

A literature search was conducted using three electronic databases and by hand-searching reference lists. English-language studies of any design which assessed F&V intake were included in the review.

Setting

Studies involving two or more European countries were included in the review.

Subjects

Healthy, free-living children or adults.

Results

The review identified fifty-one pan-European studies which assessed F&V intake. The FFQ was the most commonly used (n42), followed by 24 h recall (n11) and diet records/diet history (n7). Differences existed between the identified methods; for example, the number of F&V items on the FFQ and whether potatoes/legumes were classified as vegetables. In total, eight validated instruments were identified which assessed F&V intake among adults, adolescents or children.

Conclusions

The current review indicates that an agreed classification of F&V is needed in order to standardise intake data more effectively between European countries. Validated methods used in pan-European populations encompassing a range of European regions were identified. These methods should be considered for use by future studies focused on evaluating intake of F&V.

Validity of a web-based dietary questionnaire designed especially to measure the intake of phyto-oestrogens

A diet questionnaire (DQ) designed to assess habitual diet and phyto-oestrogen intake was developed. This study aimed to examine the validity of the DQ in men, with and without having prostate cancer. The DQ was validated against alkylresorcinol metabolites measured in urine as objective biomarkers of whole grain wheat and rye (WG) intake, and a 4-d estimated food record (FR) was used for relative comparison. Participants (n 61) completed both methods and provided spot urine samples. We found a statistically significant correlation between the DQ and FR for reported whole grain intake and isoflavonoids, as well as for intake of macronutrients, except protein. The correlation coefficient between the two methods was on average r 0·30, lowest for lignans (r -0·11) and highest for alcohol (r 0·65). Reported energy intake was lower in the DQ compared with FR (8523 v. 9249 kJ (2037 v. 2211 kcal), respectively; P = 0·014). Bland-Altman plots showed an acceptable agreement; most cases were within the limits (95 % CI) of agreement on reported energy intake, as well as intake of macronutrients, except protein (which was underestimated in the DQ compared with the FR). The correlation of alkylresorcinol with WG intake was statistically significant in the DQ (r 0·31, P = 0·015), but not in the FR (r 0·18, P = 0·12) and the weighted κ was 0·29 and 0·11, respectively. In conclusion, the results showed that the DQ have a reasonable validity for measuring WG intake and most nutrients, and, after some adjustments regarding protein intake assessment have been made, the DQ will be a promising tool.

Validity of short food questionnaire items to measure intake in children and adolescents: a systematic review

BACKGROUND

Short food questions are appealing to measure dietary intakes.

METHODS

A review of studies published between 2004 and 2016 was undertaken and these were included in the present study if they reported on a question or short item questionnaire (≤50 items, data presented as ≤30 food groups) measuring food intake or food-related habits, in children (aged 6 months to 18 years), and reported question validity or reliability. Thirty studies met the inclusion criteria.

RESULTS

Most questions assessed foods or food groups (n = 29), with the most commonly assessed being fruit (n = 22) or vegetable intake (n = 23), dairy foods and discretionary foods (n = 20 studies each). Four studies assessed food habits, with the most common being breakfast and meal frequency (n = 4 studies). Twenty studies assessed reliability, and 25 studies determined accuracy and were most commonly compared against food records. Evaluation of question performance relied on statistical tests such as correlation.

CONCLUSIONS

The present study has identified valid and reliable questions for the range of key food groups of interest to public health nutrition. Questions were more likely to be reliable than accurate, and relatively few questions were both reliable and accurate. Gaps in repeatable and valid short food questions have been identified that will provide direction for future tool development.

Development and Validation of a Mediterranean Oriented Culture-Specific Semi-Quantitative Food Frequency Questionnaire

The objectives were to develop a Mediterranean oriented semi-quantitative food frequency questionnaire (FFQ) and evaluate its validity in measuring energy and nutrient intakes. For FFQ development, the main challenge was to merge food items and practices reflecting cultural Mediterranean preferences with other food choices ensuing from diet transition to more westernized dietary patterns. FFQ validity was evaluated by comparing nutrient intakes against the average of two 24-h dietary recalls for 179 pregnant women. Although the mean intake values for most nutrients and energy tended to be higher when determined by the FFQ, the Cohen's d was below 0.3. Bland-Altman plots confirmed the agreement between the two methods. Positive significant correlations ranged from 0.35 to 0.77. The proportion of women classified correctly was between 73.2% and 92.2%, whereas gross misclassification was low. Weighted kappa values were between 0.31 and 0.78, while intraclass correlation coefficients were between 0.49 and 0.89. Our methodological approach for the development and validation of this FFQ provides reliable measurements of energy, macro- and micronutrient intakes. Overall, our culture-specific FFQ could serve as a useful assessment tool in studies aiming at monitoring dietary intakes, especially in the Mediterranean region, where countries share common cultural dietary habits.

Reproducibility and validity of a semi-quantitative FFQ for trace elements

The aim of this study was to test the reproducibility and validity of a self-administered FFQ for the Trace Element Study of Korean Adults in the Yeungnam area (SELEN). Study subjects were recruited from the SELEN cohort selected from rural and urban areas in Yeungnam, Korea. A semi-quantitative FFQ with 146 items was developed considering the dietary characteristics of cohorts in the study area. In a validation study, seventeen men and forty-eight women aged 38-62 years completed 3-d dietary records (DR) and two FFQ over a 3-month period. The validity was examined with the FFQ and DR, and the reproducibility was estimated using partial correlation coefficients, the Bland-Altman method and cross-classification. There were no significant differences between the mean intakes of selected nutrients as estimated from FFQ1, FFQ2 and DR. The median correlation coefficients for all nutrients were 0·47 and 0·56 in the reproducibility and validity tests, respectively. Bland-Altman's index and cross-classification showed acceptable agreement between FFQ1 and FFQ2 and between FFQ2 and DR. Ultimately, 78 % of the subjects were classified into the same and adjacent quartiles for most nutrients. In addition, the weighted κ value indicated that the two methods agreed fairly. In conclusion, this newly developed FFQ was a suitable dietary assessment method for the SELEN cohort study.

Associations between reported intakes of carotenoid-rich foods and concentrations of carotenoids in plasma: a validation study of a web-based food recall for children and adolescents

Objective

To validate estimated intakes of carotenoid-rich foods from a web-based food recall (WebFR) using carotenoids in blood as an objective reference method.

Design

Cross-sectional validation study using carotenoids in plasma to evaluate estimated intakes of selected carotenoid-rich foods. Participants recorded their food intake in the WebFR and plasma concentrations of β-carotene, α-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin were measured.

Setting

Schools and homes of families in a suburb of the capital of Norway.

Subjects

A total of 261 participants in the age groups 8–9 and 12–14 years.

Results

Spearman’s rank correlation coefficients ranged from 0·30 to 0·44, and cross-classification showed that 71·6–76·6 % of the participants were correctly classified, when comparing the reported intakes of carotenoid-rich foods and concentrations of the corresponding carotenoids in plasma, not including lutein and zeaxanthin.

Conclusions

Correlations were acceptable and cross-classification analyses demonstrated that the WebFR was able to rank participants according to their reported intake of foods rich in α-carotene, β-carotene, β-cryptoxanthin and lycopene. The WebFR is a promising tool for dietary assessment among children and adolescents.

Misreport of energy intake assessed with food records and 24-h recalls compared with total energy expenditure estimated with DLW

BACKGROUND/OBJECTIVES

The accuracy of dietary assessment methods has rarely been validated using precise techniques. The objective of this work was to evaluate the validity of energy intake (EI) estimated with food records (FRs) and 24-h recalls (24hRs) against total energy expenditure (EE) estimated by the doubly labeled water (DLW) method. In addition, the magnitude of EI under-reporting was assessed along with its associated characteristics.

SUBJECTS/METHODS

The studied group included 83 adults between 20 and 60 years of age who were recruited from a population-based sample. Within-person variation-adjusted means of EI estimated from two FRs and three 24hRs were compared with EE estimated using the DLW method multiple-point protocol. The Wilcoxon signed-rank test was used to assess the differences between EI and EE, whereas Bland-Altman and survival-agreement plots assessed the agreement between the estimates.

RESULTS

The mean EE (2540 kcal) was greater than the mean reported EI for both dietary assessment methods (FR: 1774 kcal; 24hR: 1658 kcal, P<0.01). The frequency of under-reporting was lower (20%) for EI estimated with the 24hR than that estimated with the FR (32%). Men presented lower magnitude of under-reported EI than women did. For women, differences between EI and EE were lower with FR than with 24hR. Overall, FR and 24hR showed similar performance. The mean under-reported EI was ~30% for both methods.

CONCLUSIONS

Irregular meal habits, smoking and low education were associated with the under-report of EI. Both FR and 24hR are subjected to bias suggesting the need of refining the procedures applied in dietary assessment methods.

Can a dietary quality score derived from a short-form FFQ assess dietary quality in UK adult population surveys?

Objective

To devise a measure of diet quality from a short-form FFQ (SFFFQ) for population surveys. To validate the SFFFQ against an extensive FFQ and a 24 h diet recall.

Design

Population-based cross-sectional survey.

Setting

East Leeds and Bolton in Northern England.

Subjects

Adults (n1999) were randomly selected from lists of those registered with a general practitioner in the study areas, contacted by mail and asked to complete the SFFFQ. Responders were sent a longer FFQ to complete and asked if they would take part in a telephone-based 24 h diet recall.

Results

Results from 826 people completing the SFFFQ, 705 completing the FFQ and forty-seven completing the diet recall were included in the analyses. The dietary quality score (DQS), based on fruit, vegetable, oily fish, non-milk extrinsic sugar and fat intakes, showed significant agreement between the SFFFQ and the FFQ (κ=0·38,P<0·001). The DQS for the SFFFQ and the diet recall did not show significant agreement (κ=0·04,P=0·312). A number of single items on the SFFFQ predicted a ‘healthy’ DQS when calculated from the FFQ. The odds of having a healthy diet were increased by 27 % (95 % CI 9, 49 %,P<0·001) for an increase in fruit of 1 portion/d and decreased by 67 % (95 % CI 47, 79 %,P<0·001) for an increase in crisps of 1 portion/d.

Conclusions

The SFFFQ has been shown to be an effective method of assessing diet quality. It provides an important method for determining variations in diet quality within and across different populations.

A meta-analysis of the validity of FFQ targeted to adolescents

Objective

The present work is aimed at meta-analysing validity studies of FFQ for adolescents, to investigate their overall accuracy and variables that can affect it negatively.

Design

A meta-analysis of sixteen original articles was performed within the ASSO Project (Adolescents and Surveillance System in the Obesity prevention).

Setting

The articles assessed the validity of FFQ for adolescents, compared with food records or 24 h recalls, with regard to energy and nutrient intakes.

Subjects

Pearson’s or Spearman’s correlation coefficients, means/standard deviations, kappa agreement, percentiles and mean differences/limits of agreement (Bland–Altman method) were extracted. Pooled estimates were calculated and heterogeneity tested for correlation coefficients and means/standard deviations. A subgroup analysis assessed variables influencing FFQ accuracy.

Results

An overall fair/high correlation between FFQ and reference method was found; a good agreement, measured through the intake mean comparison for all nutrients except sugar, carotene and K, was observed. Kappa values showed fair/moderate agreement; an overall good ability to rank adolescents according to energy and nutrient intakes was evidenced by data of percentiles; absolute validity was not confirmed by mean differences/limits of agreement. Interviewer administration mode, consumption interval of the previous year/6 months and high number of food items are major contributors to heterogeneity and thus can reduce FFQ accuracy.

Conclusions

The meta-analysis shows that FFQ are accurate tools for collecting data and could be used for ranking adolescents in terms of energy and nutrient intakes. It suggests how the design and the validation of a new FFQ should be addressed.

Assessment of Pre-Pregnancy Dietary Intake with a Food Frequency Questionnaire in Alberta Women

PURPOSE

Pre-pregnancy is an under-examined and potentially important time to optimize dietary intake to support fetal growth and development as well as maternal health. The purpose of the study was to determine the extent to which dietary intake reported by non-pregnant women is similar to pre-pregnancy dietary intake reported by pregnant women using the same assessment tool.

METHODS

The self-administered, semi-quantitative food frequency questionnaire (FFQ) was adapted from the Canadian version of the Diet History Questionnaire, originally developed by the National Cancer Institute in the United States. Pregnant women (n = 98) completed the FFQ which assessed dietary intake for the year prior to pregnancy. Non-pregnant women (n = 103) completed the same FFQ which assessed dietary intake for the previous year. Energy, macronutrients, and key micronutrients: long-chain omega-3 fatty acids, folate, vitamin B6, vitamin B12, calcium, vitamin D and iron were examined.

RESULTS

Dietary intake between groups; reported with the FFQ; was similar except for saturated fat; trans fat; calcium; and alcohol. Pregnant women reported significantly higher intakes of saturated fat; trans fat; and calcium and lower intake of alcohol in the year prior to pregnancy compared to non-pregnant women who reported intake in the previous year.

CONCLUSIONS

Despite limitations; a FFQ may be used to assist with retrospective assessment of pre-pregnancy dietary intake.

Relative Validity of a Diet History Questionnaire Against a Four-Day Weighed Food Record among Older Men in Australia: The Concord Health and Ageing in Men Project (CHAMP)

OBJECTIVES

To evaluate the relative validity of the diet history questionnaire (DHQ) used in the Concord Health and Ageing in Men Project (CHAMP) against a four-day weighed food record (4dWFR) as the reference method.

DESIGN AND MEASUREMENTS

Detailed DHQ followed by a 4dWFR were completed between July 2012 and October of 2013.

SETTING

Burwood, Canada Bay and Strathfield in Sydney, Australia.

PARTICIPANTS

Fifty six community- dwelling men aged 75 years and over (mean=79 years).

RESULTS

DHQ estimates of intakes were generally higher than estimates from 4dWFR. Differences between the two methods were generally less than 20% with the exception of β-carotene (37%). Fixed and proportional biases were only present for retinol, β-carotene, magnesium, phosphorus and percentage of energy from protein; however, 95% limits of agreement were in some cases wide. Pearson correlation coefficient of log-transformed unadjusted values ranged from 0.15 (zinc) to 0.70 (alcohol), and from 0.06 (iron) to 0.63 (thiamin) after energy-adjustment. Spearman's correlation coefficients ranged from 0.16 (zinc) to 0.80 (alcohol) before energy adjustment, and from 0.15(zinc) to 0.81(alcohol) after energy adjustment.

CONCLUSION

Our findings suggest that the DHQ used in CHAMP to measure the nutritional intake of its participants is appropriate to this age group and provides reasonably similar results to the 4dWFR for the majority of nutrients analysed.

Relative validity and reproducibility of an FFQ to determine nutrient intakes of New Zealand toddlers aged 12-24 months

OBJECTIVE

The study objective was to determine the relative validity and reproducibility of a modified FFQ for ranking the nutrient intakes of New Zealand toddlers aged 12-24 months.

DESIGN

Cross-sectional study.

SETTING

Dunedin, New Zealand.

SUBJECTS

One hundred and fifty-two participants completed a ninety-five-item FFQ twice, and five days of weighed diet recording (WDR), over one month. Validity and reproducibility were assessed for crude data and for data that were weighted for total fruit and vegetable intake (FV-adjusted).

RESULTS

De-attenuated correlations between FV-adjusted FFQ data and WDR data ranged from 0.45 (Zn) to 0.77 (Ca). The percentage classified to the correct WDR quartile by the FV-adjusted FFQ data ranged from 34.6% (total fat, Zn) to 50.3% (Fe). Average gross misclassification was 3%. Bland-Altman statistics showed crude data had a range of 128-178% agreement with the WDR and mean FV-adjusted intakes had 112-160% agreement. FV-adjusted intra-class correlations, assessing reproducibility, ranged from 0.65 (vitamin C) to 0.75 (Ca).

CONCLUSIONS

The Eating Assessment in Toddlers (EAT) FFQ showed acceptable to good relative validity, and good reproducibility, for ranking participants' nutrient intake and is able to identify toddlers at extremes of the nutrient intake distribution. It will be a useful tool for investigating toddlers' nutrient intakes in studies that require a method of dietary assessment with low respondent burden.

Validation and reproducibility of dietary assessment methods in adolescents: a systematic literature review

OBJECTIVE

The aim of the present work was to determine what dietary assessment method can provide a valid and accurate estimate of nutrient intake by comparison with the gold standard.

DESIGN

A MEDLINE, EMBASE, ISI Web of Science, Cochrane and related references literature review was conducted on dietary assessment methods for adolescents reporting the validity and/or reproducibility values. A study quality assessment on the retrieved FFQ was carried out according to two different scoring systems, judging respectively the quality of FFQ nutrition information and of FFQ validation and calibration.

SETTING

The present review considered adolescents attending high schools and recruited in hospitals or at home.

SUBJECTS

The target of the review was the healthy adolescent population in the age range 13-17 years.

RESULTS

Thirty-two eligible papers were included and analysed separately as 'original articles' (n 20) and 'reviews' (n 12). The majority (n 17) assessed the validation and reproducibility of FFQ. Almost all studies found the questionnaires to be valid and reproducible (r > 0·4), except for some food groups and nutrients. Different design and validation issues were highlighted, such as portion-size estimation, number of food items and statistics used.

CONCLUSIONS

The present review offers new insights in relation to the characteristics of assessment methods for dietary intake in adolescents. Further meta-analysis is required although the current review provides important indications on the development of a new FFQ, addressing the need for a valid, reproducible, user-friendly, cost-effective method of accurately assessing nutrient intakes in adolescents.

Image-assisted dietary assessment: a systematic review of the evidence

Images captured during eating episodes provide objective information to assist in the assessment of dietary intake. Images are captured using handheld devices or wearable cameras, and can support traditional self-report or provide the primary record of dietary intake. A diverse range of image-assisted methods have been developed and evaluated but have not been previously examined together. Therefore, a review was undertaken to examine all studies that have evaluated or validated image-assisted methods of dietary assessment for assessing dietary energy intake. Identified image-assisted methods that employ similar methodologies were grouped for comparison. English-language full-text research articles published between January 1998 and November 2013 were searched using five electronic databases. A search of reference lists and associated websites was also conducted. Thirteen studies that evaluated 10 unique image-assisted methods among adults aged 18 to 70 years were included. Ten studies used handheld devices and three studies used wearable cameras. Eight studies evaluated image-based food records, two studies explored the use of images to enhance written food records, and three studies evaluated image-assisted 24-hour dietary recalls. Results indicate images enhance self-report by revealing unreported foods and identify misreporting errors not captured by traditional methods alone. Moreover, when used as the primary record of dietary intake, images can provide valid estimates of energy intake. However, image-assisted methods that rely on image analysis can be prone to underestimation if users do not capture images of satisfactory quality before all foods are consumed. Further validation studies using criterion measures are warranted. The validity among children, adolescents, and elderly persons as well as the feasibility of using image-assisted methods in large samples needs to be examined. Additional research is also needed to better understand the potential applications and pitfalls of wearable cameras.

Biochemical validation of the older Australian's food frequency questionnaire using carotenoids and vitamin E

BACKGROUND

Validation of a food frequency questionnaire (FFQ) is important, as inaccurate and imprecise information may affect the association between dietary exposure and health outcomes.

OBJECTIVE

This study assessed the validity of the Older Australian's FFQ against plasma carotenoids and Vitamin E.

METHODS

A random subsample (n = 150) of 2420 participants in the Hunter Community Study, aged 55-85 years, were included. Correlations between crude and energy-adjusted FFQ estimates of carotenoids, Vitamin E, and fruit and vegetables with corresponding biomarkers were determined. Percentages of participants correctly classified in the same quartile, and in the same ± 1 quartile, by the two methods were calculated.

RESULTS

Significant correlations (P < 0.05) were observed for α-carotene (r = 0.26-0.28), β-carotene (r = 0.21-0.25), and β-cryptoxanthin (r = 0.21-0.23). Intakes of fruits and vegetables also showed similar correlations with these plasma carotenoids. Lycopene was only significantly correlated with fruit and vegetable intakes (r = 0.19-0.23). Weak correlations were observed for lutein + zeaxanthin (r = 0.12-0.16). For Vitamin E, significant correlation was observed for energy-adjusted FFQ estimate and biomarker (r = 0.20). More than 68% of individuals were correctly classified within the same or adjacent quartile, except for lutein + zeaxanthin.

CONCLUSION

With the exception of lutein + zeaxanthin, the Older Australian's FFQ provides reasonable rankings for individuals according to their carotenoids, Vitamin E, fruit and vegetable intakes.

Serum plant sterols as surrogate markers of dietary compliance in familial dyslipidemias

BACKGROUND & AIMS

A well-balanced diet is the first-line treatment in hyperlipidemia. The objective was to study the association between serum phytosterols and dietary patterns to use them as surrogate markers of dietary compliance in primary dyslipidemias.

METHODS

288 patients with primary hyperlipidemias (192 autosomal dominant hypercholesterolemia (ADH) and 96 familial combined hyperlipidemia (FCHL)) were included. Principal factor analysis identified 2 major dietary patterns using a 137-item food frequency questionnaire. "Vegetable & Fruits pattern" was characterized by higher intake of fruits, green beans, nuts, tomatoes, roasted or boiled potatoes, lettuce and chard and lower of processed baked goods, pizza and beer. "Western pattern" was positively characterized by hamburgers, pasta, sunflower oil, rice, chickpeas, whole milk, veal, red beans and negatively with white fish. Serum non-cholesterol sterols were determined by HPLC-MS/MS.

RESULTS

Plant sterols to-total cholesterol (TC) levels were lower with a higher adherence to a "Vegetable & Fruits pattern" (P = 0.009), mainly in ADH subjects (R(2) = 0.019). Their concentration was greater with higher compliance to "Western pattern" especially in FCHL (P = 0.014). Higher levels of synthesis markers-to-TC with a greater adherence to "Vegetable & Fruits pattern" were found (P = 0.001) (R(2) = 0.033 and R(2) = 0.109 in ADH and FCHL respectively).

CONCLUSION

In subjects with primary dislipidemia, dietary patterns associate with serum absorption and synthesis markers, but no with lipid concentrations. The influence of diet on non-cholesterol sterols levels is not powerful enough to use them as subrogate markers.

Nutrient intake in Italian infants and toddlers from North and South Italy: the Nutrintake 636 study

We performed a cross-sectional study to compare the intake of energy, macronutrients, fiber, sodium and iron and the anthropometric status of infants and toddlers living in North (Milano) and South Italy (Catania). Nutrient intake was evaluated using a 7-day weighed food record. Out of 400 planned children aged 6 to 36 months, 390 (98%) were recruited, 189 in Milano and 201 in Catania. The mean (standard deviation) age was 17 (9) months in Milano and 17 (10) months in Catania. Anthropometry, energy intake and macronutrient intake were similar in Milano and Catania. However, iron intake was 27% lower and fiber intake 16% higher in Milano than in Catania. Despite normal anthropometry and energy intake, in the pooled sample there was a high intake of proteins, simple carbohydrates, saturated fats and sodium, and a low intake of iron and fiber compared to Italian reference values. This is the first study to report the macro- and micro-nutrient intake of children aged <12 months using the 7-day weighed food record and one of the very few studies that have employed such reference method in children from the general population.

EURRECA-Estimating folate requirements for deriving dietary reference values

In most countries, the dietary folate intake associated with adequate status of red cell folate and/or serum folate provides the basis for formulating reference values. One of the major challenges in setting dietary reference values for folate, however, is the need to account for the differences in bioavailability between the natural forms of the vitamin and the synthetic form, folic acid, albeit to date, few countries in Europe take bioavailability into consideration. A series of systematic reviews that included only those studies which used the most robust measures of both folate intake and folate status were carried out by the EURRECA Network of Excellence to examine the relationships between folate intake, status, and a number of health outcomes relevant to specific stages of the lifecycle. This review summarizes the available evidence and the issues to consider in the setting of dietary reference values for folate.

Validity and reproducibility of a Spanish dietary history

Objective

To assess the validity and reproducibility of food and nutrient intake estimated with the electronic diet history of ENRICA (DH-E), which collects information on numerous aspects of the Spanish diet.

Methods

The validity of food and nutrient intake was estimated using Pearson correlation coefficients between the DH-E and the mean of seven 24-hour recalls collected every 2 months over the previous year. The reproducibility was estimated using intraclass correlation coefficients between two DH-E made one year apart.

Results

The correlations coefficients between the DH-E and the mean of seven 24-hour recalls for the main food groups were cereals (r = 0.66), meat (r = 0.66), fish (r = 0.42), vegetables (r = 0.62) and fruits (r = 0.44). The mean correlation coefficient for all 15 food groups considered was 0.53. The correlations for macronutrients were: energy (r = 0.76), proteins (r = 0.58), lipids (r = 0.73), saturated fat (r = 0.73), monounsaturated fat (r = 0.59), polyunsaturated fat (r = 0.57), and carbohydrates (r = 0.66). The mean correlation coefficient for all 41 nutrients studied was 0.55. The intraclass correlation coefficient between the two DH-E was greater than 0.40 for most foods and nutrients.

Conclusions

The DH-E shows good validity and reproducibility for estimating usual intake of foods and nutrients.

A systematic review and meta-analysis of dietary patterns and depression in community-dwelling adults

BACKGROUND

Studies of single nutrients on depression have produced inconsistent results, and they have failed to consider the complex interactions between nutrients. An increasing number of studies in recent years are investigating the association of overall dietary patterns and depression.

OBJECTIVE

This study aimed to systematically review current literature and conduct meta-analyses of studies addressing the association between dietary patterns and depression.

DESIGN

Six electronic databases were searched for articles published up to August 2013 that examined the association of total diet and depression among adults. Only studies considered methodologically rigorous were included. Two independent reviewers completed study selection, quality rating, and data extraction. Effect sizes of eligible studies were pooled by using random-effects models. A summary of the findings was presented for studies that could not be meta-analyzed.

RESULTS

A total of 21 studies were identified. Results from 13 observational studies were pooled. Two dietary patterns were identified. The healthy diet pattern was significantly associated with a reduced odds of depression (OR: 0.84; 95% CI: 0.76, 0.92; P < 0.001). No statistically significant association was observed between the Western diet and depression (OR: 1.17; 95% CI: 0.97, 1.68; P = 0.094); however, the studies were too few for a precise estimate of this effect.

CONCLUSIONS

The results suggest that high intakes of fruit, vegetables, fish, and whole grains may be associated with a reduced depression risk. However, more high-quality randomized controlled trials and cohort studies are needed to confirm this finding, specifically the temporal sequence of this association.

Relative validity of a food frequency questionnaire to assess nutrient intake in pregnant women

BACKGROUND

To date, there are no food frequency questionnaires that have been validated to assess nutrient intakes in pregnant women in Ireland. The present study aimed to assess the relative validity of a self-administered food frequency questionnaire during pregnancy.

METHODS

The food frequency questionnaire was administered once during pregnancy between 12 and 34 weeks. Participants also completed a 3-day food diary during each trimester of pregnancy (reference method) and intakes from both the food frequency questionnaire and the mean of the 3-day food diaries were compared in a sample of 130 participants from the control arm of an intervention study.

RESULTS

Energy-adjusted Pearson's correlation coefficients ranged from 0.24 (riboflavin) to 0.59 (magnesium) and were all statistically significant (P < 0.05). The food frequency questionnaire tended to report higher energy and nutrient intakes compared to the food diaries. On average, 74% of participants were classified into the same ± 1 quartile and 7% into opposing quartiles by the two methods.

CONCLUSIONS

Overall, our food frequency questionnaire showed good relative validity. We conclude that a single administration of a food frequency questionnaire is a valid tool for ranking women in accordance with their nutrient intakes during pregnancy.

The quality of dietary intake methodology and reporting in child and adolescent obesity intervention trials: a systematic review

Assessing dietary intake is important in evaluating childhood obesity intervention effectiveness. The purpose of this review was to evaluate the dietary intake methods and reporting in intervention studies that included a dietary component to treat overweight or obese children. A systematic review of studies published in the English language, between 1985 and August 2010 in health databases. The search identified 2,295 papers, of which 335 were retrieved and 31 met the inclusion criteria. Twenty-three studies reported energy intake as an outcome measure, 20 reported macronutrient intakes and 10 studies reported food intake outcomes. The most common dietary method employed was the food diary (n = 13), followed by 24-h recall (n = 5), food frequency questionnaire (FFQ) (n = 4) and dietary questionnaire (n = 4). The quality of the dietary intake methods reporting was rated as 'poor' in 15 studies (52%) and only 3 were rated as 'excellent'. The reporting quality of FFQs tended to be higher than food diaries/recalls. Deficiencies in the quality of dietary intake methods reporting in child obesity studies were identified. Use of a dietary intake methods reporting checklist is recommended. This will enable the quality of dietary intake results to be evaluated, and an increased ability to replicate study methodology by other researchers.

The relative validity and reproducibility of an iron food frequency questionnaire for identifying iron-related dietary patterns in young women

BACKGROUND

Using food frequency data to identify dietary patterns is a newly emerging approach to assessing the relationship between dietary intake and iron status. Food frequency questionnaires should be assessed for validity and reproducibility before use.

OBJECTIVE

We aimed to investigate the relative validity and reproducibility of an iron food frequency questionnaire (FeFFQ) specifically designed to identify iron-related dietary patterns.

DESIGN

Participants completed the FeFFQ at baseline (FeFFQ1) and 1 month later (FeFFQ2) to assess reproducibility. A 4-day weighed diet record (4DDR) was completed between these assessments to determine validity. Foods appearing in the 4DDR were classified into the same 144 food groupings as the FeFFQ. Factor analysis was used to determine dietary patterns from FeFFQ1, FeFFQ2, and the 4DDR.

PARTICIPANTS/SETTING

A convenience sample of women (n=115) aged 18 to 44 years living in Auckland, New Zealand, during 2009.

STATISTICAL ANALYSES PERFORMED

Agreement between diet pattern scores was compared using correlation coefficients, Bland-Altman analysis, cross-classification, and the weighted κ statistic.

RESULTS

A "healthy" and a "sandwich and drinks" dietary pattern were identified from all three dietary assessments. Correlation coefficients between FeFFQ1 and the 4DDR diet pattern scores (validity) were 0.34 for the healthy, and 0.62 for the sandwich and drinks pattern (both Ps<0.001). Correlation coefficients between the two FeFFQs (reproducibility) were 0.76 for both the healthy and sandwich and drinks pattern (P<0.001). The FeFFQ1 correctly classified >50% of participants into the correct tertile and <10% into the opposite tertile for both the healthy and sandwich and drinks diet pattern scores when compared with the 4DDR and FeFFQ2.

CONCLUSIONS

The FeFFQ appears to be a reproducible and relatively valid method for identifying dietary patterns, and could be used to investigate the relationship between dietary patterns and iron status.

Micronutrient intake and status in Central and Eastern Europe compared with other European countries, results from the EURRECA network

Objective

To compare micronutrient intakes and status in Central and Eastern Europe (CEE) with those in other European countries and with reference values.

Design

Review of the micronutrient intake/status data from open access and grey literature sources from CEE.

Setting

Micronutrients studied were folate, iodine, Fe, vitamin B12 and Zn (for intake and status) and Ca, Cu, Se, vitamin C and vitamin D (for intake). Intake data were based on validated dietary assessment methods; mean intakes were compared with average nutrient requirements set by the Nordic countries or the US Institute of Medicine. Nutritional status was assessed using the status biomarkers and cut-off levels recommended primarily by the WHO.

Subjects

For all population groups in CEE, the mean intake and mean/median status levels were compared between countries and regions: CEE, Scandinavia, Western Europe and Mediterranean.

Results

Mean micronutrient intakes of adults in the CEE region were in the same range as those from other European regions, with exception of Ca (lower in CEE). CEE children and adolescents had poorer iodine status, and intakes of Ca, folate and vitamin D were below the reference values.

Conclusions

CEE countries are lacking comparable studies on micronutrient intake/status across all age ranges, especially in children. Available evidence showed no differences in micronutrient intake/status in CEE populations in comparison with other European regions, except for Ca intake in adults and iodine and Fe status in children. The identified knowledge gaps urge further research on micronutrient intake/status of CEE populations to make a basis for evidence-based nutrition policy.

Validation of a FFQ for estimating ω-3, ω-6 and trans fatty acid intake during pregnancy using mature breast milk and food recalls

BACKGROUND/OBJECTIVES

To assess the performance of a food frequency questionnaire (FFQ) for estimating ω-3, ω-6 and trans fatty acid intake during pregnancy. Moreover, we determined whether the fatty acid composition of mature breast milk represents a valuable biomarker for fatty acid intake during pregnancy.

SUBJECTS/METHODS

A prospective study in 41 pregnant women, aged 18-35 years, was conducted. Food intake during pregnancy was evaluated by three 24-h recalls (24 hR), and 2 FFQ. The fatty acid composition of mature breast milk was determined by gas chromatography. The method of triads and joint classification between quartiles of intake were applied.

RESULTS

The FFQ was accurate for estimating docosahexanoic (DHA), linoleic and total ω-6 fatty acids according to validity coefficients. Higher agreements (>70%) into the same or adjacent quartiles between the dietary methods were found for α-linolenic, total ω-3, linoleic and trans fatty acid intake. High validity coefficients for eicosapentanoic (EPA) and DHA acids of human milk were found (0.61 and 0.73, respectively), and the method was adequate for categorizing the intake of α-linolenic, total ω-3 and trans fatty acids compared with FFQ estimates, and for arachidonic acid and trans fatty acids compared with food recall estimates, during pregnancy.

CONCLUSIONS

The FFQ was an accurate tool for categorizing α-linolenic, total ω-3 and trans fatty acid intake. According to the validity coefficients observed, the FFQ accurately estimated DHA, linoleic and total ω-6 fatty acids and the composition of mature breast milk was shown to be a suitable biomarker for EPA and DHA fatty acid intake during pregnancy.

Dietary assessment methods for intakes of iron, calcium, selenium, zinc and iodine

The EURopean micronutrient RECommendations Aligned (EURRECA) Network of Excellence is working towards developing aligned micronutrient recommendations across Europe. The purpose of the present study was to conduct a review of methods used in validation studies carried out in adults assessing dietary intake of EURRECA priority minerals. A search strategy and inclusion criteria were defined and a scoring system was developed to rate the quality of each validation study that produced a quality index with possible scores obtained ranging from 0.5 to 7. A MEDLINE and EMBASE literature review was conducted. Articles/validation studies meeting the inclusion criteria included: 79/88 for Fe; 95/104 for Ca; 13/15 for Se; 29/30 for Zn; 7/9 for iodine. The most frequently used method to ascertain dietary intake was the Food Frequency Questionnaire (FFQ), whereas dietary records (DR) and 24 h recalls were the most used reference methods. The correlation coefficients (CC) between study mineral intakes estimated by FFQ and the reference method were weighted according to the study's quality index and obtained acceptable to good ratings, ranging from 0.36 to 0.60 when the reference method was DR and from 0.41 to 0.58 when the reference was 24 h recalls. A minority of studies (n 9) used biomarkers for validation and among these, five included iodine obtaining a CC of 0.47. The FFQ was seen as a valid method for assessing mineral intake, particularly for Ca and, to a lower extent, for iodine and Zn. Se and Fe showed only acceptable correlations. The present review provides new insights regarding the characteristics that assessment methods for dietary mineral intakes should fulfil.

Dietary assessment methods for micronutrient intake: a systematic review on vitamins

The EURRECA Network of Excellence is working towards the development of aligned micronutrient recommendations across Europe. The purpose of the present study was to define how to identify dietary intake validation studies in adults pertaining to vitamins. After establishing a search strategy, we conducted a MEDLINE and EMBASE literature review. A scoring system was developed to rate the quality of each validation study according to sample size, statistical methods, data collection procedure, seasonality and vitamin supplement use. This produced a quality index with possible scores obtained ranging from 0.5 to 7. Five thousand four-hundred and seventy-six papers were identified. The numbers meeting the inclusion criteria were: for vitamin A, 76; vitamin C, 108; vitamin D, 21; vitamin E, 75; folic acid, 47; vitamin B12, 19; vitamin B6, 21; thiamine, 49; riboflavin, 49; and niacin, 32. The most frequently used method to ascertain dietary intake was the Food Frequency Questionnaire (FFQ), whereas dietary records (DR) and 24-h recalls were the most used reference methods. The correlation coefficients (CC) between vitamin intakes estimated by FFQ and the reference method were weighted according to the study's quality index and ranged from 0.41 to 0.53 when the reference method was the DR and from 0.43 to 0.67 when the reference was 24-h recalls. A minority of studies (n 33) used biomarkers for validation and in these the CC ranged from 0.26 to 0.38. The FFQ is an acceptable method of assessing vitamin intake. The present review provides new insights regarding the characteristics that assessment methods for dietary intake should fulfil.