Design aspects of 24 h recall assessments may affect the estimates of protein and potassium intake in dietary surveys.

OBJECTIVE: To evaluate the impact of different modes of administration (face-to-face v. telephone), recall days (first v. second), days of the week (weekday v. weekend) and interview days (1 d later v. 2 d later) on bias in protein and K intakes collected with 24 h dietary recalls (24-HDR). DESIGN: Two non-consecutive 24-HDR (collected with standardised EPIC-Soft software) were used to estimate protein and K intakes by a face-to-face interview at the research centres and a telephone interview, and included all days of the week. Two 24 h urine collections were used to determine biomarkers of protein and K intake. The bias in intake was defined as the ratio between the 24-HDR estimate and the biomarker. SETTING: Five centres in Belgium, Czech Republic, France, the Netherlands and Norway in the European Food Consumption Validation (EFCOVAL) study. SUBJECTS: About 120 adults (aged 45-65 years) per centre. RESULTS: The bias in protein intake in the Czech Republic and Norway was smaller for telephone than face-to-face interviews (P = 0·01). The second 24-HDR estimates of protein intake in France and K intake in Belgium had a larger bias than the first 24-HDR (P = 0·01 and 0·04, respectively). In the Czech Republic, protein intake estimated during weekends and K intake estimated during weekdays had a larger bias than during other days of the week (P = 0·01). In addition, K intake collected 2 d later in the Czech Republic was likely to be overestimated. CONCLUSIONS: The biases in protein and K intakes were comparable between modes of administration, recall days, days of the week and interview days in some, but not all, study centres.

Development of a nutrition knowledge questionnaire for obese adults.

BACKGROUND AND OBJECTIVE: The aim of this study was to develop a questionnaire for assessing nutritional knowledge among overweight adults. The questionnaire should reveal knowledge about current dietary recommendations, sources of nutrients, everyday food choices, and conditions related to overweight. DESIGN: The first draft of the nutrition knowledge questionnaire (113 items) was based on literature review. To ensure content validity and expert-assessed face validity, an expert panel examined the questionnaire. Thereafter, the questionnaire was tested for user friendliness and ambiguity by five students. The questionnaire was pilot tested in a group of obese adults, similar to the target group. The results were analyzed for item difficulty and internal consistency and comments made by respondents were taken into account. Two student groups, differing in nutritional expertise, answered the questionnaire on two occasions to test construct validity and test-retest reliability. After the retest, a total overview of the questionnaire was made by the expert panel. The final questionnaire consisted of 91 items. SUBJECTS: The pilot study was conducted in obese adults waiting for a gastric bypass operation (n=33). Construct validity (n=34) and test-retest reliability (n=27) was tested in two student groups: public health nutrition students and construction students. RESULTS: Results from the pilot study showed that internal consistency of the three first sections together was 0.84, measured by Cronbach's α. Test of construct validity showed that public health nutrition students scored significantly better than construction students (p<0.001 for all sections), and test-retest reliability for all sections together was 0.82 (Pearson's r). CONCLUSION: The knowledge questionnaire had reasonable content-, face-, and construct validities and overall good reliability. The questionnaire can be a useful tool for measuring nutrition knowledge among obese adults.

Relative validity of fruit and vegetable intake estimated from an FFQ, using carotenoid and flavonoid biomarkers and the method of triads.

The aim of the present study was to validate the intakes of fruit, juice and vegetables from an FFQ. In sub-study I (n 147), intakes from the FFQ were evaluated against 7 d weighed food records (WR) and plasma carotenoid concentrations, whereas in sub-study II (n 85), the intakes were evaluated against plasma carotenoid concentrations and amounts of flavonoids in 24 h urine samples. Relative validity was evaluated by comparing median intakes, estimating correlation coefficients and validity coefficients using the method of triads. In sub-study I, we observed no significant difference in daily median fruit intake between the FFQ and the WR, whereas the intake of vegetables was higher from the FFQ than from the WR. The correlations between intakes from the FFQ and the WR ranged from 0·31 to 0·58. In sub-study II, the intakes of fruit and vegetables correlated significantly with plasma carotenoid concentrations and urinary flavonoids. The validity coefficients for the intakes of fruit and vegetables from the FFQ ranged from 0·61 to 0·88 in sub-study I and from 0·60 to 0·94 in sub-study II. In summary, based on the associations observed between intakes from the FFQ and the biomarkers and the FFQ validity coefficients, the FFQ was found valid and suitable for ranking individuals according to their usual intake of fruit, juice and vegetables.

Two non-consecutive 24 h recalls using EPIC-Soft software are sufficiently valid for comparing protein and potassium intake between five European centres--results from the European Food Consumption Validation (EFCOVAL) study.

The use of two non-consecutive 24 h recalls using EPIC-Soft for standardised dietary monitoring in European countries has previously been proposed in the European Food Consumption Survey Method consortium. Whether this methodology is sufficiently valid to assess nutrient intake in a comparable way, among populations with different food patterns in Europe, is the subject of study in the European Food Consumption Validation consortium. The objective of the study was to compare the validity of usual protein and K intake estimated from two non-consecutive standardised 24 h recalls using EPIC-Soft between five selected centres in Europe. A total of 600 adults, aged 45-65 years, were recruited in Belgium, the Czech Republic, France, The Netherlands and Norway. From each participant, two 24 h recalls and two 24 h urines were collected. The mean and distribution of usual protein and K intake, as well as the ranking of intake, were compared with protein and K excretions within and between centres. Underestimation of protein (range 2-13%) and K (range 4-17%) intake was seen in all centres, except in the Czech Republic. We found a fair agreement between prevalences estimated based on the intake and excretion data at the lower end of the usual intake distribution (< 10% difference), but larger differences at other points. Protein and K intake was moderately correlated with excretion within the centres (ranges = 0·39-0·67 and 0·37-0·69, respectively). These were comparable across centres. In conclusion, two standardised 24 h recalls (EPIC-Soft) appear to be sufficiently valid for assessing and comparing the mean and distribution of protein and K intake across five centres in Europe as well as for ranking individuals.

Evaluation of energy and dietary intake estimates from a food frequency questionnaire using independent energy expenditure measurement and weighed food records.

BACKGROUND: We have developed a food frequency questionnaire (FFQ) for the assessment of habitual diet, with special focus on the intake of fruit, vegetables and other antioxidant-rich foods and beverages. The aim of the present study was to evaluate the relative validity of the intakes of energy, food and nutrients from the FFQ. METHODS: Energy intake was evaluated against independent measures of energy expenditure using the ActiReg® system (motion detection), whereas 7-days weighed food records were used to study the relative validity of food and nutrient intake. The relationship between methods was investigated using correlation analyses and cross-classification of participants. The visual agreement between the methods was evaluated using Bland-Altman plots. RESULTS: We observed that the FFQ underestimated the energy intake by approximately 11% compared to the energy expenditure measured by the ActiReg®. The correlation coefficient between energy intake and energy expenditure was 0.54 and 32% of the participants were defined as under-reporters. Compared to the weighed food records the percentages of energy from fat and added sugar from the FFQ were underestimated, whereas the percentage of energy from total carbohydrates and protein were slightly overestimated. The intake of foods rich in antioxidants did not vary significantly between the FFQ and weighed food records, with the exceptions of berries, coffee, tea and vegetables which were overestimated. Spearman's Rank Order Correlations between FFQ and weighed food records were 0.41 for berries, 0.58 for chocolate, 0.78 for coffee, 0.61 for fruit, 0.57 for fruit and berry juices, 0.40 for nuts, 0.74 for tea, 0.38 for vegetables and 0.70 for the intake of wine. CONCLUSIONS: Our new FFQ provides a good estimate of the average energy intake and it obtains valid data on average intake of most antioxidant-rich foods and beverages. Our study also showed that the FFQs ability to rank participants according to intake of total antioxidants and most of the antioxidant-rich foods was good.

High intake of added sugar among Norwegian children and adolescents.

OBJECTIVE: It is debated whether the intake of added sugar displaces micronutrient-rich foods and dilutes the nutrient density of the diet, and whether there is a link between sugar and the increased rate of obesity. The objectives of this study were to examine the effect of added sugar on the intakes of energy, micronutrients, fruit and vegetables, and to examine the association between intake of added sugar and age, sex, body mass index, physical activity, inactivity and parents' education. DESIGN: Participants recorded their food intake in pre-coded food diaries for 4 days and filled in a questionnaire about physical activity, watching television (TV)/using a personal computer (PC) and parents' education. SUBJECTS: Three hundred and ninety-one 4-year-olds, 810 students in the 4th grade (9 years old) and 1005 in the 8th grade (13 years old) were included in the study. RESULTS: The intakes of all nutrients, except alpha-tocopherol among 4-year-olds and vitamin C among 4-year-olds and 4th graders, decreased with increasing content of added sugar in the diet. Moreover, high consumers of added sugar had a 30-40% lower intake of fruit and vegetables than did low consumers. A negative association was observed between consumption of added sugar and body mass index among girls in the 8th grade (P=0.013), whereas a positive association was observed among 4-year-old boys (P=0.055). Associations between physical activity, hours spent watching TV/using a PC, parents' education and the energy intake from added sugar varied in the different age groups. CONCLUSIONS: This study showed a negative association between the intake of added sugar and intakes of micronutrients, fruit and vegetables. The negative association between sugar intake and intake of fruit and vegetables is important from a public health perspective, since one of the main health messages today is to increase current intake of fruit and vegetables.