Diet quality of Montreal-area adults needs improvement: estimates from a self-administered food frequency questionnaire furnishing a dietary indicator score

OBJECTIVE/DESIGN: Time and budget constraints limit nutrition evaluation in Canadian health surveys. To encourage regular population diet monitoring in Canada, we developed and assessed the relative validity of a population-based food frequency questionnaire (FFQ) to assess usual diet in Quebecers. A 73-item, self-administered semiquantitative FFQ was designed in French and English from the Block National Cancer Institute Health Habits and History Questionnaire to capture usual food consumption among Quebec adults. The US Department of Agriculture Healthy Eating Index (HEI) (maximum score=100) was adapted to Canadian age- and sex-specific dietary recommendations, validated, and programmed to score the FFQ for diet quality. SUBJECTS: The FFQ was pretested, pilot tested, and administered by mail to a random sample of 248 adults aged 18 to 82 years in the Montreal area (57% women) who were recruited by random digit dialing (64% response rate). A subgroup (n=94) furnished four nonconsecutive 1-day food records for validation of the FFQ. RESULTS: Mean FFQ energy intakes were 2,216 kcal (median 2,110 kcal) for men and 1,785 kcal (median 1,680 kcal) for women. Proportional median macronutrient consumption was similar in both sexes at 17% protein, 34% to 35% fats, and 48% to 49% carbohydrates, but differed by age group in women. Adequacy of micronutrient intakes relative to Dietary Reference Intakes varied by age, sex, and nutrient. Whereas most mean or median intakes were at or exceeded recommendations, calcium intakes were low overall and levels of several other nutrients were very low at the 10th percentile. Mean Canadian HEI (range 46 to 99) was higher in women (74.9) than men (70.3, P<.001). Women's scores showed they met recommendations for intakes of vegetables and fruit, cholesterol, and sodium better than men (P ranged from <.01 to <.0001), while men fared better at meeting recommended fat intake levels (P<.05). CONCLUSIONS: The Canadian HEI adequately discriminates overall diet quality based on dietary data estimated from our FFQ. Examination of subscores within and between quartiles may best reveal which food groups require attention to improve diet quality, providing valuable information for teaching and planning. Future studies should test diet quality indicators in populations recruited to reflect greater dietary diversity and reporting ability and include members of disadvantaged groups to provide a broader set of behaviors that could shed light on factors influencing diet quality.     

Validity and systematic error in measuring carotenoid consumption with dietary self-report instruments

Vegetables and fruits are rich in carotenoids, a group of compounds thought to protect against cancer. Studies of diet-disease associations need valid and reliable instruments for measuring dietary intake. The authors present a measurement error model to estimate the validity (defined as correlation between self-reported intake and "true" intake), systematic error, and reliability of two self-report dietary assessment methods. Carotenoid exposure is measured by repeated 24-hour recalls, a food frequency questionnaire (FFQ), and a plasma marker. The model is applied to 1,013 participants assigned between 1995 and 2000 to the nonintervention arm of the Women's Healthy Eating and Living Study, a randomized trial assessing the impact of a low-fat, high-vegetable/fruit/fiber diet on preventing new breast cancer events. Diagnostics including graphs are used to assess the goodness of fit. The validity of the instruments was 0.44 for the 24-hour recalls and 0.39 for the FFQ. Systematic error accounted for over 22% and 50% of measurement error variance for the 24-hour recalls and FFQ, respectively. The use of either self-report method alone in diet-disease studies could lead to substantial bias and error. Multiple methods of dietary assessment may provide more accurate estimates of true dietary intake.     

Nutrient Database Development: A Historical Perspective from the Framingham Nutrition Studies

Food frequency questionnaires (FFQs) are commonly used in nutritional epidemiology to assess habitual eating habits. Development of an appropriate food and nutrient database is required for translating information derived from FFQs into estimates of nutrient intake, dietary quality, or for absolute or rank-ordered nutritional risk assessment. We discuss the procedures used recently in designing a historical nutrient database to analyze an FFQ administered in 1984-1988 to Framingham Offspring-Spouse Study members. This systematic approach should inform other research in the field. The self-administered 145-item Framingham FFQ is semi-quantitative with seven nonoverlapping response categories to determine annual consumption frequency. The database development process included selection of the US Department of Agriculture's Nutrient Database for Standard Reference as the primary raw data source, expansion of the 145 FFQ line items to code individual foods to assign nutrient values, a selection process to match foods to appropriate nutrition codes for nutrient information, and a statistical model to calculate nutrient intakes. The historical database contains 449 foods and nutrient data for all 29 nutrients available in 1985. The adequacy with which an FFQ can provide reliable diet assessment data depends on the integrity of the underlying database. We outlined a systematic protocol to derive usual dietary intake from an FFQ using a robust nutrient database that is appropriate for the Framingham Offspring-Spouse Study FFQ and its assessment time-frame. The database can be updated to accommodate changes in the food supply and eating behaviors and creates a foundation for future nutrition research.     

Epidemiological assessment of diet: a comparison of a 7-day diary with a food frequency questionnaire using urinary markers of nitrogen, potassium and sodium

BACKGROUND: Validation studies of dietary instruments developed for epidemiological studies have typically used some form of diet record as the standard for comparison. Recent work suggests that comparison with diet record may overestimate the ability of the epidemiological instrument to measure habitual dietary intake, due to lack of independence of the measurement errors. The degree of regression dilution in estimating diet-disease association may therefore have been correspondingly underestimated. Use of biochemical measures of intake may mitigate the problem. In this paper, we report on the use of urinary measures of intakes of nitrogen, potassium and sodium to compare the performance of a semi-quantitative food frequency questionnaire (FFQ) and a 7-day diet diary (7DD) to estimate average intake of these nutrients over one year. METHODS: In all, 179 individuals were asked to complete an FFQ and a 7DD on two occasions separated by approximately 12 months. The individuals were also asked to provide 24-hour urine samples on six occasions over a 6-9-month period, covering the time at which the record FFQ and 7DD were completed. The urine was assayed for nitrogen, potassium and sodium. The protocol was completed by 123 individuals. The data from these individuals were analysed to estimate the covariance structure of the measurement errors of the FFQ, the 7DD and a single 24-hour urine measurement, and to estimate the degree of regression dilution associated with the FFQ and 7DD. RESULTS: The results demonstrated that: (1) the error variances for each of the three nutrients was more than twice as great with the FFQ than the 7DD; (2) there was substantial correlation (0.46-0.58) between the error of both the FFQ and the 7DD completed on different occasions; (3) there was moderate correlation (0.24- 0.29) between the error in the FFQ and the error in the 7DD for each nutrient; (4) the correlation between errors in different nutrients was higher for the FFQ (0.77-0.80) than for the 7DD (0.52-0.70). CONCLUSIONS: The regression dilution with the FFQ is considerably greater than with the 7DD and also, for the nutrients considered, greater than would be inferred if validation studies were based solely on record or diary type instruments.     

Development and validation of a food frequency questionnaire for the assessment of dietary total antioxidant capacity

The total antioxidant capacity (TAC) of the diet may be an important tool to monitor the protective effect of plant foods in epidemiological studies. We developed a semi-quantitative FFQ for the assessment of dietary TAC by 3 different assays, i.e., Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP) and ferric reducing-antioxidant power (FRAP). The FFQ consists of 53 questions about the major sources of dietary TAC in Northern Italy and was validated against a 3-d weighed food record (3D-WR) in 285 individuals (159 males and 126 females) aged 35-88 y and living in the province of Parma (Italy). Plasma TAC was also evaluated in a subgroup of subjects using the TEAC and FRAP assays. The FFQ was associated with 3D-WR (quadratic-weighted kappa = 0.49 for TEAC, 0.53 for TRAP, and 0.49 for FRAP; P < 0.0001) and proved reasonably accurate to classify individuals into quartiles of TAC intake. The FFQ had a good repeatability when readministered after 1 y in 55 subjects (quadratic-weighted kappa for intertertile agreement = 0.66 for TEAC, 0.70 for TRAP and 0.68 for FRAP; P < 0.0001). With both dietary instruments, the main contributors to TAC intake were coffee and tea in women and alcoholic beverages in men, followed by fruits and vegetables in both sexes. Plasma TAC and dietary TAC were not associated. In conclusion, our FFQ has the potential for being used to rank subjects on the basis of their antioxidant intake as determined by dietary TAC in large epidemiological studies. The FFQ should be validated in external populations before being used for research purposes.     

Validation of a food frequency questionnaire for assessing dietary nutrients in Brazilian children 5 to 10 years of age

OBJECTIVE: This study aimed to assess the relative validity of a food frequency questionnaire (FFQ), previously validated to measure usual intakes in adults, for measuring dietary intakes in children 5 to 10 y of age. METHODS: Dietary intakes were measured using an FFQ and a 3-d dietary record. Healthy children, 5 to 10 y old (n = 151), were recruited from public schools and asked to answer the questions in the FFQ and to provide non-consecutive 3-d dietary records based on reported estimated portion sizes. Paired sample t tests and Pearson's correlation coefficients were conducted to determine whether the two instruments reported similar values for energy and nutrients. The agreement of quartile categorization between the two instruments was also examined. RESULTS: Estimated energy and nutrient intakes derived from the FFQ were significantly higher than those derived from 3-d dietary records. As expected, Pearson's correlations increased after adjusting for residual measurement error, presumably due to exclusion of the high within-person variability in intake of these nutrients. Moderate to high (r > 0.50) correlation coefficients were verified for some nutrients such as calcium, folate, vitamin B2, vitamin A, and vitamin C. CONCLUSION: This FFQ, originally developed for use in adults, appears to overestimate usual energy and nutrient intakes in children 5 to 10 y of age. Further work is necessary to conduct a calibration study to establish adequate portion sizes before instrument adoption in this population.     

Evaluation of 2 brief instruments and a food-frequency questionnaire to estimate daily number of servings of fruit and vegetables

BACKGROUND: Measurement of fruit and vegetable intake is important in the surveillance of populations and in epidemiologic studies that examine the relations between diet and disease. Some situations require the use of brief dietary assessment tools. OBJECTIVE: Our objective was to evaluate the performance of 2 brief dietary assessment instruments, a 7-item standard screener and a new 16-item screener, and a complete food-frequency questionnaire (FFQ) in measuring total fruit and vegetable consumption. DESIGN: About 800 men and women from the National Institutes of Health-AARP Diet and Health Study completed an FFQ, 1 of the 2 screeners, and two 24-h dietary recalls. Fruit and vegetable intakes as measured by each screener and the FFQ were compared with estimated true usual intake by using a measurement-error model. RESULTS: Median daily servings of fruit and vegetables were underestimated by both screeners. The estimated agreement between true intake and the screener was higher for the new screener than for the standard screener and was higher for women than for men. The estimated agreement between true intake and the FFQ was higher than that for both screeners. Attenuation coefficients for the FFQ and screeners were comparable. CONCLUSIONS: For estimating median intakes of fruit and vegetables and the prevalence of recommended intakes being met, the use of screeners without appropriate adjustment is suboptimal. For estimating relative risks in the relations between fruit and vegetable intake and disease, screeners and this FFQ are similar in performance.     

Comparison of dietary assessment methods in a low-fat dietary intervention program

The food frequency questionnaire (FFQ) is commonly utilized for assessment of dietary fat intake, but its validity among individuals following a low-fat diet is unclear. We evaluated the agreement of nutrient estimates derived from FFQ, 24-h recall, and 3-day food records obtained from 104 participants in a randomized trial of a low-fat dietary intervention for women at elevated breast cancer risk. Comparisons were made for total calories, percent calories from fat, and total fat after 1 yr. Correlation was assessed using standard methods based on a null hypothesis of no agreement between instruments as well as by a methodology based on a null hypothesis that the instruments should be in agreement. With the use of standard methods, FFQ estimates for women on the low-fat diet were significantly correlated to records only for percent calories from fat (r = 0.39), whereas recall and record estimates were significantly correlated for all three dietary variables. Using the new method, we found no significant correlation between FFQ and either recalls or records for women following a low-fat diet but significant correlation between recall and record estimates for total calories (r = 0.67). Traditional correlation testing may overestimate the extent of agreement in dietary instruments among women on a low-fat diet. We found empirical support for the nontraditional method.     

Comparison of a short food-frequency questionnaire and derived indices with a seven-day diet record in Belgian and Italian children

Summary Objectives:  To compare food group intakes and dietary indices estimated from a 14-item food frequency questionnaire (FFQ) with a seven day diet record. Methods:  112 Belgian and 114 Italian children (11–12 years) completed the FFQ followed by a seven-day diary (FD) and a retest one week later. Dietary indices were calculated from the FFQ and the FD. Results:  Spearman’s correlations between the FFQ items and the diary varied between –0.13 and 0.67. When comparing the FFQ with the FD an overestimation was found for most items. The Excess Index was significantly correlated with energy intake (respectively 0.35 and 0.25 for Belgian and Italian children); the Variety Index with fiber intake (0.26 for both) and Calcium intake (respectively 0.32 and 0.41); the Fiber Index with fiber intake (respectively 0.30 and 0.37) and the Calcium Index with Calcium intake (respectively 0.47 and 0.50). Conclusion:  When the FFQ is used for estimating consumption frequencies, overestimation must be considered. The ability to rank individuals varies considerably between food items. The Calcium index can be useful in situations requiring brief dietary instruments. The value of the other indices is lower although still associations in the expected directions were found. Submitted: 25 October 2007; Revised: 04 May 2008; Accepted: 25 June 2008     

Reproducibility and validity of dietary glycemic index, dietary glycemic load, and total carbohydrate intake in 141 Swedish men

BACKGROUND: Although the associations of dietary glycemic index (GI) and dietary glycemic load (GL) with many chronic diseases have been examined in epidemiologic studies, information regarding the reproducibility and validity of these measures assessed with the use of food-frequency questionnaires (FFQs) is lacking. OBJECTIVE: We examined the reproducibility and validity of dietary GI and dietary GL and of carbohydrate intake as assessed by using an FFQ. DESIGN: Swedish men (n = 141) aged 40-74 y completed 2 FFQs 1 y apart and two 1-wk weighed diet records 6 mo apart. Dietary GI, dietary GL, and carbohydrate intake (starches and sugars) were calculated from both FFQs and diet records. We used intraclass correlations between the 2 FFQs to measure reproducibility and Pearson correlations between the diet records and the FFQs to assess the relative validity. RESULTS: Reproducibility of the FFQs was 0.66 (95% CI: 0.56, 0.75) for dietary GI, 0.61 (95% CI: 0.50, 0.71) for dietary GL, and 0.61 (95% CI: 0.50, 0.71) for carbohydrate. The correlations between the FFQs and diet records were 0.62 (95% CI: 0.45, 0.74) for dietary GI, 0.77 (95% CI: 0.56, 0.88) for dietary GL, and 0.76 (95% CI: 0.55, 0.88) for carbohydrate after adjustment for within-person variation in the FFQs and diet records. CONCLUSION: In this sample of men, an FFQ measured dietary GI, dietary GL, and carbohydrate with reproducibility and validity similar to other commonly studied nutritional factors.     

Validation of a food frequency questionnaire for use in a Scottish population: correlation of antioxidant vitamin intakes with biochemical measures

Background: The food frequency questionnaire (FFQ) has become established as the primary method for assessing dietary intake in epidemiological studies of diet and disease; attention must now be given to developing and evaluating FFQs that extend the range of populations studied. Aim: To assess the validity of antioxidant vitamin intake estimates derived from a self-administered food frequency questionnaire which was developed for use in Scottish populations. Method: Intake estimates of vitamins A, C, E and β-carotene were compared with corresponding biochemical measurements in 273 Scottish men and women aged 39–45 years. Results: The mean ratios of energy intake to calculated basal metabolic rate were 1.40 for men and 1.46 for women suggesting that the intake values derived from the FFQ were not biased towards under-reporting. Significant positive correlation coefficients ranging from 0.14 (for vitamin A) to 0.42 (for vitamin C) were observed between total intake (including diet and supplements) and plasma values. Adjustment for other known determinants of diet and plasma values (i.e. energy intake, body mass index, gender, smoking and plasma lipid levels) improved the correlations for vitamin E and β-carotene. Excluding supplement users generally reduced the correlations suggesting that failure to include supplemental sources may result in misclassification of antioxidant vitamin intake. The food frequency questionnaire assigned 68–89% of subjects correctly into the upper or lower plus adjacent tertiles of plasma vitamin concentration. Conclusions: These results demonstrate that the food frequency questionnaire is a valid measure of antioxidant vitamin intake.     

Estimating the alcohol–breast cancer association: a comparison of diet diaries, FFQs and combined measurements

The alcohol-breast cancer association has been established using alcohol intake measurements from Food Frequency Questionnaires (FFQ). For some nutrients diet diary measurements are more highly correlated with true intake compared with FFQ measurements, but it is unknown whether this is true for alcohol. A case-control study (656 breast cancer cases, 1905 matched controls) was sampled from four cohorts in the UK Dietary Cohort Consortium. Alcohol intake was measured prospectively using FFQs and 4- or 7-day diet diaries. Both relied on fixed portion sizes allocated to given beverage types, but those used to obtain FFQ measurements were lower. FFQ measurements were therefore on average lower and to enable fair comparison the FFQ was "calibrated" using diet diary portion sizes. Diet diaries gave more zero measurements, demonstrating the challenge of distinguishing never-from episodic-consumers using short term instruments. To use all information, two combined measurements were calculated. The first is an average of the two measurements with special treatment of zeros. The second is the expected true intake given both measurements, calculated using a measurement error model. After confounder adjustment the odds ratio (OR) per 10?g/day of alcohol intake was 1.05 (95?% CI 0.98, 1.13) using diet diaries, and 1.13 (1.02, 1.24) using FFQs. The calibrated FFQ measurement and combined measurements 1 and 2 gave ORs 1.10 (1.03, 1.18), 1.09 (1.01, 1.18), 1.09 (0.99,1.20), respectively. The association was modified by HRT use, being stronger among users versus non-users. In summary, using an alcohol measurement from a diet diary at one time point gave attenuated associations compared with FFQ.     

Validation of a short food frequency questionnaire in Australian adults

The aim of this article is to report on the validity and internal consistency of a short food frequency questionnaire (FFQ) to measure dietary intake in Australian adults. A total of 407 individuals completed the short FFQ. The Cronbach’s alpha of 0.66 indicated acceptable internal consistency for the FFQ. Content validity was measured using factor analysis showed that 35% of total variance was explained by factor analysis. The FFQ was also validated against 31 3-day food records (FR). No significant difference between average intake of energy, most macronutrients, and some micronutrients between two instruments was identified. An acceptable levels of correlation (0.39–0.69) was observed between the two instruments. Bland and Altman’s plots showed relative agreement in both instruments with potential bias in measuring iron and iodine. The current FFQ can be an acceptable tool to quickly measuring dietary intake in Australian adults.     

Validity of a self-administered food-frequency questionnaire in the estimation of amino acid intake

The objective of the present study was to evaluate the validity of a FFQ in the estimation of dietary amino acid intake. Amino acid intake was calculated using a composition database developed based on the Standard Tables of Food Composition for amino acids in Japan. Subjects were subsampled from two populations of the Japan Public Health Center-based Prospective Study who volunteered to participate in the validation study of the FFQ. The first group was from the population the FFQ was developed for (internal population; n 215) and the second was a separate population to confirm external validity (external population; n 350). The validity of the FFQ was evaluated using 28 d weighed dietary records (DR) as a reference method. Spearman's rank correlation coefficients (CC) between amino acid intake from the FFQ and DR were calculated. The dietary intake of amino acids was slightly underestimated by the FFQ. Deattenuated CC of energy-adjusted amino acid intake according to the FFQ and corresponding amino acid intake according to the DR ranged from 0.15 to 0.52. The median CC for twenty amino acids were 0.33 for men and 0.25 for women in the internal population, and 0.40 for men and 0.30 for women in the external population. In conclusion, the validity of the FFQ in estimating amino acid intake was low to moderate.     

Fruit and vegetable assessment: performance of 2 new short instruments and a food frequency questionnaire

Objective To evaluate the ability of 2 new short assessment instruments and a food frequency questionnaire (FFQ) to measure intake of fruit and vegetables. The “All-Day” screener asks frequency and portion size questions about 9 food items. The “By-Meal” screener is similar, except that it asks about 2 of those 9 food items in terms of mealtime.

Design Survey participants completed 4 telephone-administered 24-hour dietary recalls over 1 year, a self-administered FFQ 1 to 2 months later, and 1 of 2 self-administered screeners after an additional 7 months.

Subjects/setting Participating were 202 men and 260 women aged 20 to 70 years living throughout the United States.

Statistical analyses Fruit and vegetable intakes measured by each screener and the FFQ were compared with true usual intake based on a measurement error model with 24-hour dietary recalls as the reference instrument.

Results Estimates of median daily servings of fruit and vegetables were as follows: For men: True intake (5.8) vs All-Day screener (5.0), By-Meal screener (5.5), and FFQ (6.6); for women: true intake (4.2) vs All-Day screener (5.0), By-Meal screener (5.4), and FFQ (6.2). Estimated correlations between the test instruments and true intake were as follows: For men: All-Day screener (0.66), By-Meal screener (0.67), FFQ (0.68); for women: All-Day screener (0.51), By-Meal screener (0.53), and FFQ (0.54).

Applications/conclusions Both screeners might be useful to estimate median intakes of fruit and vegetable servings in US populations, but they might be less useful in accurately ranking individuals. More research is needed before using the screeners in ethnic or low-literacy populations. J Am Diet Assoc. 2002;102:1764-1772.     

Development of a simple food frequency questionnaire to estimate intakes of calcium and other nutrients for the prevention and management of osteoporosis

There have been no simple methods to estimate dietary nutrient intakes for the prevention and management of osteoporosis. The aim of this study was to develop and validate a new, simple food frequency questionnaire (FFQ) for dietary intake of calcium and other nutrients relevant to the bone health of adult Japanese women. We developed a 28-item FFQ. To validate this, 208 and 72 adult women aged between 18 and 69 y were recruited for testing reliability and reproducibility, respectively. In the 208 women, moderate-to-high Spearman's correlation coefficients between our FFQ and the conventional diet record method were found in intakes of calcium (r=0.668), sodium chloride (NaCl) (r=0.475), vitamin A (r=0.501), vitamin D (r=0.413), vitamin K (r=0.649), and energy (r=0.471). In the 72 women, coefficients of variance of the four repeated measurements of intakes throughout a year were 14.1% for calcium, 7.3% for NaCl, 21.2% for vitamin A, 13.6% for vitamin D, 36.8% for vitamin K, and 9.6% for energy. In conclusion, the FFQ we developed is a useful tool to evaluate the intake of dietary calcium of adult Japanese women. Although it can also measure intakes of dietary vitamin A, vitamin D, vitamin K, NaCl, and energy, further improvement is needed to measure intakes of these nutrients and energy.     

Validity and Reproducibility of a Food Frequency Questionnaire to Assess Macro and Micro-Nutrient Intake among a Convenience Cohort of Healthy Adult Qataris

This study aimed at developing a valid culture-sensitive quantitative food frequency questionnaire (FFQ) for Qatari adults. A convenient sample of healthy Qataris (n = 107) were recruited from family members of Qatar University students. The Diet History Questionnaire II of the US National Cancer Institute was translated to Arabic language, back-translated to English, pilot tested, and then modified accordingly to be used in Qatari setting. Participants were asked to complete the translated version of the FFQ. This FFQ was then validated against three 24 h diet recall (24 hDR) including a weekend day. Participants were asked to complete the FFQ again after one-month period to measure its repeatability. Dietary data were analyzed using the dietary analysis software ESHA. The validity and reliability of FFQ were assessed by comparing the median intake of nutrients and foods and by calculating the Pearson correlation coefficients. The median nutrient intakes assessed by the second FFQ were higher than that reported in the baseline FFQ1 except for fat. The percentage of increase varies between 1.5% and 96%. Results of the second FFQ indicated an overestimation of intake for most nutrients (macro and micro). Macronutrient intakes assessed by the two FFQ and 24 hDR were strongly correlated. The correlation coefficients for micronutrient intakes between FFQ2 and 24hDR were lower than that of the two FFQs except for calcium (r = 0.55) and sodium (r = 0.643). They ranged from (−0.17) for fluorine to (0.643) for sodium. The agreement rates for classifying macronutrient intakes into same or adjacent quartile were between 79.4% and 100% for the two FFQs and between 71% and 100% for the second FFQ and 24hDR. The reported consumption of food groups estimated by FFQ2 was significantly higher than that reported by FFQ1. In conclusion, the developed FFQ was sufficiently valid to assess energy and macronutrients but not micronutrients. The reliability was adequate for most nutrients.     

A Cross-Sectional Pilot Study on Food Intake Patterns Identified from Very Short FFQ and Metabolic Factors Including Liver Function in Healthy Japanese Adults

Non-alcoholic fatty liver disease is a growing health problem, and rapid diet assessment is required for personal nutrition education. This pilot study aimed to clarify associations between current food intake patterns identified from the short food frequency questionnaire (FFQ) and metabolic parameters, including liver function. We conducted a cross-sectional study on Japanese non-alcoholic residents of Tokyo and surrounding districts, 20 to 49 years of age. Anthropometric measurements, fasting blood samples, three-day dietary records, and FFQ with 21 items were collected. In all 198 participants, the proportions with obesity were 21% in men and 6% in women. Hypertriglyceridemia was significant only in men, affecting 26%. The traditional Japanese (TJ) pattern (greater intakes of green and yellow vegetables, other vegetables, seaweed/mushrooms/konjac, dairy, fruits, fish, salty, and soybeans/soy products) and the Westernized pattern (greater intakes of saturated-fat-rich foods, oily, egg/fish-eggs/liver, and sweets) were identified. The TJ pattern score showed an inverse relationship with body mass index, triglyceride, alkaline-phosphatase, leucine-aminopeptidase, and fatty liver index. The TJ pattern identified from the short FFQ was suggested to be associated with body fat storage. Further large-scale studies are needed to clarify the associations between this dietary pattern and metabolic parameters, including liver function.     

Self-reported energy intake by FFQ compared with actual energy intake to maintain body weight in 516 adults

It is generally assumed that a FFQ is not suitable to estimate the absolute levels of individual energy intake. However, in epidemiological studies, reported nutrients by FFQ are often corrected for this intake. The objective of the present study was to assess how accurately participants report their energy intakes by FFQ. We compared reported energy intake with actual energy intake needed to maintain stable body weights during eleven controlled dietary trials. FFQ were developed to capture at least 90 % of energy intake. Participants, 342 women and 174 men, with a mean BMI of 22.8 (SD 3.1) kg/m2 filled out the FFQ just before the trials. Energy intakes during the trials were calculated from provided foods and reported free-food items, representing 90 and 10 % of energy intake, respectively. Mean reported energy intake was 97.5 (SD 12.7) % of actual energy intake during the trials; it was 98.9 (SD 15.2) % for women and 94.7 (SD 16.3) % for men (P = 0.004 for difference between sexes). Correlation coefficients between reported and actual energy intakes were 0.82 for all participants, 0.74 for women and 0.80 for men. Individual reported energy intake as a percentage of actual intake ranged from 56.3 to 159.6 % in women and from 43.8 to 151.0 % in men. In conclusion, the FFQ appeared to be accurate for estimating the mean level of energy intakes of these participants and for ranking them according to their intake. However, the large differences found on the individual level may affect the results of epidemiological studies in an unknown direction if nutrients are corrected for energy intakes reported by FFQ.