Objective: To test the validity of a colour food photography atlas for quantifying portion size eaten compared with weighed foods. Design: The colour food photography atlas was prepared by cooking, weighing and taking digital photographs of three portion sizes of 434 foods and beverages typical of the Italian diet. Subjects and interventions: In all, 448 male and female volunteers aged 6-60 y from a wide variety of social backgrounds completed 9075 assessments of food portions eaten at lunch and dinner in relation to a set of colour food photographs during 8 weeks of investigation. The amounts of foods eaten by individuals in five different cafeterias in Pavia, Northern Italy, were weighed by trained investigators at the time of serving and, within 5-10 min of the end of the meal, each subject was asked to quantify all foods consumed with reference to one of the three food photographs or in terms of virtual portions among those shown in the photographs.Results: Multiple regression analysis shows that weights of portion sizes chosen from the set of photographs are significantly associated (Po0.05) to weights of eaten portions (b ¼ 0.81; R 2 ¼ 0.70) and are independent of age, gender and BMI. The differences between mean weights of the portions chosen by individuals from photographs and mean weights of eaten foods are significant for all food categories (Po0.05), except for bread. However, because of the very large number of observations, the mean differences are very small (range: from þ 23.2 g ( þ 11.2%) for first courses to À1.3 g (À2.7%) for bread). Bland-Altman plots show that first courses limits of agreement are wide because the dispersion is increasing while weights are rising. Conclusions: The use of a series of three photographs and virtual portion sizes being associated with relatively small errors, our findings support the validity of using this colour food photography atlas as a tool for quantifying food portion size in epidemiological dietary surveys on different age groups of Italian subjects.

Objective: To develop a dietary questionnaire on food habits, eating behaviour and nutrition knowledge of adolescents and to examine its reliability. Design: A cross-sectional baseline survey. The questionnaire was self-administered to study participants twice with 7 days between each administration. Setting: A school community in Pavia, Italy. Subjects: A group of students (n ¼ 72, aged 14-17 y, both sexes) studying in a secondary school in the second year of the course were invited to compile a dietary questionnaire during school time. Informed written consent was obtained from each subject and their parents. Subjects were initially recruited for a nutrition intervention; recruitment was opportunistic and school based. Statistical analyses: Reliability was assessed using the Cronbach's alpha and the Pearson correlation coefficients. Results: Cronbach's alpha ranges from a minimum of 0.55 to a maximum of 0.75, indicating that only two sections have a poor internal consistency. The Pearson correlation coefficients range from a minimum of 0.78 to a maximum of 0.88, indicating a very good temporal stability of the questionnaire. All the Pearson correlation coefficients are statistically significant with Po0.01. Conclusions:The present questionnaire has the potential to measure the effects of nutrition interventions on adolescents because of its stability in making comparisons over time. The instruments is low in cost and easy to administer and analyse; moreover, it could be modified appropriately to fit the needs of other populations as well.

Objective: The study aimed to test the reliability of a nutrition questionnaire and to assess potential associations between nutrition knowledge, food consumption and lifestyle behaviours, controlling for sociodemographic factors. Design: Cross-sectional survey. Setting: Comprehensive school in the municipality of Butera, a rural area of Sicily, South Italy. Subjects: The survey was conducted between March and May 2010 on 445 students (4-16 years). Results: All constructs of the questionnaire had statistically significant Cronbach's a and Pearson's correlation coefficients, showing good internal consistency and temporal stability. After controlling for covariates, nutrition knowledge was positively associated with pasta/rice, fish, vegetable and fruit intakes, and negatively with sweets, snacks, fried foods and sugary drinks consumption. Moreover, students whose parents were in the highest educational and occupational categories reported eating significantly more fruits and vegetables and less meat, sweets, snacks, fried foods and sugary drinks. Students with higher nutrition knowledge scores were less likely to have two or more snacks daily and to spend more than 3 h in sedentary activities daily (OR 5 0?89, 95 % CI 0?83, 0?97 and OR 5 0?92, 95 % CI 0?86, 0?99, respectively). High parental education was associated with less frequent snacking and more frequent weekly physical activity, compared with lower categories, whereas high parental occupational category was associated with daily breakfast. Conclusions: Improving nutrition knowledge in children and young adolescents may translate into educating them in good dietary habits. Moreover, nutrition intervention programmes should also involve parents to improve dietary quality and nutritional habits of the entire family.

The results point out unhealthy behaviors influencing adolescents' eating habits and suggest which of these must be considered in order to develop tailored nutrition interventions, improving adolescents' consciousness aimed at adopting a healthy lifestyle.

The significant role of trace elements in human health is well documented. Trace elements are those compounds that need to be present in the human diet to maintain normal physiological functions. However, some microelements may become harmful at high levels of exposure, or, on the other hand, may give rise to malnutrition, when their exposure is too low. The aim of the present study was to provide a reliable estimate of the dietary exposure of twenty-one trace elements in a Northern Italian area. For this purpose, trace element analyses were undertaken on total diet samples collected from a university cafeteria in Pavia, Northern Italy. The average daily exposure for the adult people was calculated on the basis of food consumption frequency, portion size and trace element levels in foodstuffs. The mean exposure values satisfy the Italian RDA for all the essential trace elements, except for Fe exposure in females, and are well below the Provisional Tolerable Daily Intake for all the toxic compounds, showing that the probability of dietary exposure to health risks is overall small. As far as Fe exposure is concerned, a potential risk of anaemia in the female adult population should be considered, then studies aimed at evaluating the Fe nutritional status of adult Italian women should be addressed. In conclusion, while not excluding the possibility that the daily exposure determined in the present study may not be representative of the population as a whole, this study provides a good estimate of the Italian adult consumer exposure to twenty-one trace elements.