Choosing the best method to estimate the energy density of a population using food purchase data.

BACKGROUND: Energy density (ED) is a measure of the energy content of a food component or diet relative to a standard unit of weight. Widespread variation in ED assessment methodologies exist. The present study aimed to explore the feasibility of calculating the ED of the Scottish diet using UK food purchase survey data and to identify the most appropriate method for calculating ED for use in the development of a Scottish Dietary Goal that captures any socioeconomic differences. METHODS: Energy density was calculated using five different methods [food; food and milk; food, milk and energy containing (non-alcoholic) beverages; food, milk and all non-alcoholic beverages; and all food and beverages]. ED of the Scottish diet was estimated for each of the ED methods and data were examined by deprivation category. RESULTS: Mean ED varied from 409 to 847 kJ 100 g(-1) depending on the method used. ED values calculated from food (847 kJ 100 g(-1) ) and food and milk (718 kJ 100 g(-1) ) were most comparable to other published data, with the latter being a more accurate reflection of all food consumed. For these two methods, there was a significant gradient between the most and least deprived quintiles (892-807 and 737-696 kJ 100 g(-1) for food and food and milk, respectively). CONCLUSIONS: Because the World Cancer Research Fund recommendations are based on ED from food and milk, it was considered prudent to use this method for policy purposes and for future monitoring work of the Scottish Diet to ensure consistency of reporting and comparability with other published studies.

Validity and reliability of a short questionnaire for assessing the impact of cooking skills interventions.

BACKGROUND: Food skills programmes are widely used as a means to improve confidence in food preparation, the use of basic food skills and food selections amongst low income communities. However, the impact of such interventions are rarely evaluated as a result of a lack of validated assessment tools appropriate for use within this target group. METHODS: A two-page questionnaire utilising a closed-question format was designed based on key domains known to be influenced by cooking skills programmes. Content validity was assessed by a panel of public health experts and face validity by individuals, typical of those who may attend cooking skills classes. Internal and repeat reliability were assessed with groups of adults attending community-based classes. The feasibility of using the tool in community settings was also assessed. RESULTS: The draft questionnaire was amended as appropriate subsequent to content and face validity testing. Cronbach's alpha for confidence and knowledge sections was 0.86 and 0.84, respectively, indicating good internal consistency. Spearman correlation coefficients for repeat reliability testing between time 1 and time 2 for each item were in the range 0.46-0.91 (all significant at P < 0.001), indicating that the questionnaire elicited stable responses for repeated use. Feasibility testing highlighted the need for detailed instructions for course tutors on how to distribute and check questionnaires for completion. CONCLUSIONS: This tool provides a standardised method of evaluating cooking skills interventions that could be utilised in the development and evaluation of multicentre cooking skills interventions.

Validity and reliability testing of a short questionnaire developed to assess consumers' use, understanding and perception of food labels.

BACKGROUND: Food labels may have an important function in communicating nutrition information and have considerable potential to influence food choice and dietary behaviour. OBJECTIVES: To assess the validity and reliability of a short (self-complete) questionnaire designed to measure consumers' use and understanding of food labels. METHODS: Questionnaire content was determined by gaps highlighted in a literature review of food labelling. Nineteen questions (49 items) assessing frequency of label reading perceived importance of food labels, regularity of dining out, desire to have nutrition information at specific catering outlets and ability to perform nutrition information tasks were formulated and presented on four pages of A4. With the exception of two open-ended questions, all items were presented as closed (field box) structures. Content validity, face validity, item analysis, repeat and internal reliability were assessed. RESULTS: Nutrition experts (26) completed detailed content validity assessment, resulting in high scores for appropriateness, importance and phrasing of questions, although grammar and terminology changes were required. Face validity indicated that the questionnaire was quick to complete (<15 min), easy to follow and comprehensible. Cronbach's alpha scores (internal reliability) for questions with multiple sections ranged from 0.72 to 0.91, indicating good internal consistency. Repeat reliability testing showed Spearman's correlation coefficients ranging from 0.51 to 0.97 (all P<0.001) showing high temporal stability. Item Difficulty analysis indicated that questions (Section C only) were at an appropriate level (with P between 20 and 80% for all items). Item discrimination analysis ranged from r=0.43 to 0.70, highlighting that items were suitable for inclusion. CONCLUSIONS: This questionnaire is a suitable tool for assessing consumers' use, understanding and perception of food labels.

Making an informed choice in the catering environment: what do consumers want to know?

BACKGROUND: Eating outside the home is common in the UK, but it remains difficult for consumers to make informed choices based on menu information. The present study examines the reported preferences for the provision of nutrition (salt, fat and energy) and ingredient information in six types of UK catering outlets. METHODS: Participants completed a short postal survey, assessing their frequency of dining at specific catering establishments as well as their desire to see nutrition and ingredient information. RESULTS: The responses from 786 adults aged >or=18 years (of whom 65% claimed to be 'motivated to eat a healthy diet') indicated that over 40% reported eating at a catering outlet at least once a week. Over half said that they would wish to see information on ingredients and the salt content of menu items at all venues. Preference for information on energy and fat content was less popular and varied in the range 42-56% for energy and 47-59% for fat. It is notable that 43% of respondents said they would welcome information on energy content of menu items in restaurants. CONCLUSION: A significant proportion of consumers wish to see information on the ingredients and nutrition composition on menu items for sale in UK catering outlets. Such information is likely to raise an awareness and understanding of healthy food choices and assist the population in making informed choices about healthy eating.

Estimation of portion size in children's dietary assessment: lessons learnt.

BACKGROUND/OBJECTIVES: Assessing the dietary intake of young children is challenging. In any 1 day, children may have several carers responsible for providing them with their dietary requirements, and once children reach school age, traditional methods such as weighing all items consumed become impractical. As an alternative to weighed records, food portion size assessment tools are available to assist subjects in estimating the amounts of foods consumed. Existing food photographs designed for use with adults and based on adult portion sizes have been found to be inappropriate for use with children. This article presents a review and summary of a body of work carried out to improve the estimation of portion sizes consumed by children. METHODS: Feasibility work was undertaken to determine the accuracy and precision of three portion size assessment tools; food photographs, food models and a computer-based Interactive Portion Size Assessment System (IPSAS). These tools were based on portion sizes served to children during the National Diet and Nutrition Survey. As children often do not consume all of the food served to them, smaller portions were included in each tool for estimation of leftovers. The tools covered 22 foods, which children commonly consume. Children were served known amounts of each food and leftovers were recorded. They were then asked to estimate both the amount of food that they were served and the amount of any food leftover. RESULTS: Children were found to estimate food portion size with an accuracy approaching that of adults using both the food photographs and IPSAS. CONCLUSIONS: Further development is underway to increase the number of food photographs and to develop IPSAS to cover a much wider range of foods and to validate the use of these tools in a 'real life' setting.

Children's estimates of food portion size: the development and evaluation of three portion size assessment tools for use with children.

A number of methods have been developed to assist subjects in providing an estimate of portion size but their application in improving portion size estimation by children has not been investigated systematically. The aim was to develop portion size assessment tools for use with children and to assess the accuracy of children's estimates of portion size using the tools. The tools were food photographs, food models and an interactive portion size assessment system (IPSAS). Children (n 201), aged 4-16 years, were supplied with known quantities of food to eat, in school. Food leftovers were weighed. Children estimated the amount of each food using each tool, 24 h after consuming the food. The age-specific portion sizes represented were based on portion sizes consumed by children in a national survey. Significant differences were found between the accuracy of estimates using the three tools. Children of all ages performed well using the IPSAS and food photographs. The accuracy and precision of estimates made using the food models were poor. For all tools, estimates of the amount of food served were more accurate than estimates of the amount consumed. Issues relating to reporting of foods left over which impact on estimates of the amounts of foods actually consumed require further study. The IPSAS has shown potential for assessment of dietary intake with children. Before practical application in assessment of dietary intake of children the tool would need to be expanded to cover a wider range of foods and to be validated in a 'real-life' situation.

Children's estimates of food portion size: the effect of timing of dietary interview on the accuracy of children's portion size estimates.

For food intakes to be converted into nutrient intakes a measure or estimate of the amount of food consumed is required. A number of methods have been developed to assist subjects in providing an estimate of portion size. Children's ability to use perception, conceptualisation and memory skills to estimate food portion size has not been investigated systematically. The aim of the present study was to test the effect of the timing of a dietary interview on the accuracy of estimates of food portion sizes made by children, using food photographs, food models and an interactive portion size assessment system, developed for use with children and based on portion sizes of foods consumed by children. Children (n 108) aged 4-14 years were supplied with known quantities of foods and asked to estimate the portion size of each food using each of the three portion size assessment tools. Interviews took place (a) with the food in view, (b) just after the child had eaten the food or (c) 24 h after the child had eaten the food. There were no significant differences in children's ability to estimate food portion size (either as served or as eaten) with timing of interview. That is, children were as accurate in their estimates of portion size 24 h after consuming the food as when the food was in view. Under these conditions many children were able to estimate food portion size utilising perception, conceptualisation and memory skills.

Factors that affect the food choices made by girls and young women, from minority ethnic groups, living in the UK.

BACKGROUND: Lower birth weight, often found in infants from minority ethnic groups, may be partly because of the disproportionate representation of ethnic minority groups in low-income areas. To develop an intervention, to improve the nutritional intake of young women from populations at risk of low-birth-weight babies, which would be culturally sensitive and well received by the intended recipients, a community development approach was used to investigate factors that might influence food choice and the nutritional intake of girls and young women from ethnic minority groups. METHODS: Focus group discussions were conducted across the UK, to explore factors that might affect the food choices of girls and young women of African and South Asian decent. The data was analysed using deductive content analysis (Qual. Soc. Res., 1, 2000, 1). Discussions were around the broad themes of buying and preparing food, eating food and dietary changes, and ideas for an intervention to improve diet. RESULTS: The focus group discussions indicated that all the communities took time, price, health and availability into consideration when making food purchases. The groups were also quite similar in their use of 'Western' foods which tended to be of the fast food variety. These foods were used when there was not enough time to prepare a 'traditional' meal. CONCLUSION: Many issues that affect the food choice of people who move to the UK are common within different ethnic groups. The idea of a practical intervention based on improving cooking skills was popular with all the groups.

Childhood obesity and socioeconomic status: a novel role for height growth limitation.

OBJECTIVE: To assess prevalence and socioeconomic context of overweight and obesity in a cohort of Scottish children. DESIGN: Cross-sectional study. SETTING: Primary schools in Dundee, Angus, and Fife, Eastern Scotland, UK. PARTICIPANTS: A total of 1240 boys and 1214 girls aged between 4-10 y. MAIN OUTCOME MEASURE: Weight, height and body mass index (weight/height2). RESULTS: Overall overweight or obesity prevalence was 24.6%, while prevalence of obesity alone was 6.1%. Individuals from schools with a high level of low-income families were 65% more likely to be overweight as judged by BMI. However, these children weighed the same as more affluent children of the same age, but were 1.26 cm shorter. CONCLUSION: These data confirm the continued increase in childhood obesity in the UK and reveal a role for height-growth limitation in the absence of overall growth restriction, among children from low-income groups. This observation raises important questions regarding socioeconomic environmental factors in promoting the currently increasing levels of obesity.

The Pro12Ala and C-681G variants of the PPARG locus are associated with opposing growth phenotypes in young schoolchildren.

AIMS/HYPOTHESIS: Peroxisome proliferator-activated receptor gamma is an important regulator of adiposity in mouse and man, and common variation in the PPARG gene has been associated with birthweight, adult obesity, insulin sensitivity and type 2 diabetes. We hypothesised that these variants may be associated with childhood obesity. METHODS: Height and weight were recorded for 2454 prepubertal children aged between 4 and 10 years, who were then genotyped for three common variants of the PPARG locus: C-681G, Pro12Ala and C1431T. RESULTS: No single variant of PPARG was significantly associated with height, weight or BMI. However, when modelling the variants together we detected an opposing interaction between the -681G and the Ala12 variants in height and weight, but not BMI (p=0.018, 0.013 and 0.119 respectively). The data were consistent with the Ala12 carriers being deficient in energy storage/utilisation, leading to reduced growth. In contrast, the -681G variant, which has been associated with increased adult height, was associated with accelerated growth. The two variants were in strong linkage disequilibrium. However, rare individuals bearing the isolated variants demonstrated the greatest variation from the mean, the most contrasting genotypes being associated with a variation of 7 kg in weight and 6 cm in height, standardised to 7.4-year-olds (p=0.006 and p=0.02 respectively). CONCLUSIONS/INTERPRETATION: This study demonstrates that quantitative trait analysis of energy balance/growth and the PPARG locus is complex and requires the use of multiple genetic markers.

Fluoride supplements and changes in tooth decay on the Island of Tristan da Cunha: 1966-1996.

BACKGROUND: The island of Tristan Da Cunha is one of the few examples in the world of a remote enclosed community. The inhabitants of the island were transported to England in 1961 as a result of a volcanic eruption and during their time in England they received a detailed dental health examination. They were later examined back on the island in 1966 by Dr John Fisher and in 1982 a school fluoride supplementation programme was introduced. AIM: The present paper reports the results of the first dental health survey to be carried out on the island since the introduction of a regular school fluoride supplementation programme in 1982. SUBJECTS AND METHODS: A cohort of 6-19-year-old subjects on the island were examined in 1996 using a similar protocol to that which was used by Fisher in the 1966 examination. RESULTS: Comparing the 6-12-year-olds who were caries free in 1966 with those caries free in 1996 using the Chi-squared statistic reveals a statistically significant greater number caries free in the more recent cohort (X2 - 6.0, P- 0.014). For the older age group (13-19 years), a similar comparison reveals a highly statistically significant difference(Z2 - 12.26, P 0.005). CONCLUSIONS: A significant increase in the number of caries free 6-19-year-old children in Tristan Da Cunha between 1966 and 1996 was noted: 1) This is a significant finding in the light of the school fluoride supplementation programme that was introduced on the island in 1982; and 2) Appropriate fluoride supplementation regimes may have conferred a protective effect in a group of children with a cariogenic diet. The paper discusses the significance of this study in the support of fluoridation as a method of reducing the prevalence of dental caries a nd also discusses possibilities for future research on the island of Tristan Da Cunha.

The development and pilot evaluation of a nutrition education intervention programme for pregnant teenage women (food for life).

BACKGROUND: A healthy diet in pregnancy is important for both maternal and infant health but this may be difficult to achieve particularly for groups such as teenage pregnant women, many of whom are from disadvantaged backgrounds. To our knowledge this is the first report of a practical nutrition education programme for this group in the UK. METHOD: An intervention was designed incorporating seven informal food preparation sessions, which allowed opportunities for discussion of nutritional, and other topics (e.g. food safety and well-being in pregnancy). Midwives in a community centre setting led the sessions. The acceptability of the package to participants and midwives was recorded and pre- and post-intervention data collected on sociodemographic details, dietary intake (using an eating-habits questionnaire and a 24-h dietary recall) and cooking skills. RESULTS: The midwives found the package easy to follow and use. The 16 (of the 120 invited) women who attended found the courses helpful but objective evaluation of dietary intake was not possible because of poor compliance. CONCLUSIONS: The nutrition education programme was favourably received by midwives and the women who participated. However recruitment was problematic and alternative methods of delivering and evaluating such a package should be investigated.

Is there a relationship between the food intakes of Scottish 5(1/2)-8(1/2)-year-olds and those of their mothers?

BACKGROUND: Recent reports have highlighted certain aspects of the diets of children and adults in Scotland today that are a cause for concern. If there are significant associations between family members in food choice and thus in nutrient intakes, this may be important in the aetiology and prevention of diseases relating to dietary risk factors. AIM: To compare the food intake of Scottish children aged 5(1/2)-8(1/2) years with that of their mothers. METHODS: As part of a larger study, data on food intakes were obtained from 4-day weighed food records for 36 Scottish children (12 boys and 24 girls), aged 5(1/2)-8(1/2) years, who had participated in the 1992/1993 National Diet and Nutrition Survey (NDNS), and their mothers. RESULTS: Compared with their mothers, children had higher median densities [weight (g) of foods per 4.2 MJ (1000 kcal)] of snack foods including fruit, bread and confectionery and lower median densities of meat and meat products, fish, potatoes and vegetables. Positive, significant correlations between children and mothers were found for median densities of bread (r = 0.360, P < 0.05), fruit (r = 0.735, P < 0.001) and potatoes (r = 0.572, P < 0.001) and also for chips (r = 0.651, P < 0.001) and chocolate confectionery (r = 0.368, P < 0.05), the latter two being foods that should be reduced in the average Scottish diet. CONCLUSIONS: Children's intakes of snack foods were correlated with that of their mothers emphasizing the need for change at a family level if current guidelines on diet are to be implemented.

Plasma vitamin C and food choice in the third Glasgow MONICA population survey.

STUDY OBJECTIVE: To determine the contribution of different foods to the estimated intakes of vitamin C among those differing in plasma vitamin C levels, and thereby inform dietary strategies for correcting possible deficiency. DESIGN: Cross sectional random population survey. SETTING: North Glasgow, Scotland, 1992. PARTICIPANTS: 632 men and 635 women, aged 25 to 74 years, not taking vitamin supplements, who participated in the third MONICA study (population survey monitoring trends and determinants of cardiovascular disease). MEASUREMENTS AND MAIN RESULTS: Dietary and sociodemographic information was collected using a food frequency and lifestyle questionnaire. Plasma vitamin C was measured in non-fasted venous blood samples and subjects categorised by cut points of 11.4 and 22.7 micromol/l as being of low, marginal or optimal vitamin C status. Food sources of dietary vitamin C were identified for subjects in these categories. Plasma vitamin C concentrations were compared among groups classified according to intake of key foods. More men (26%) than women (14%) were in the low category for vitamin C status; as were a higher percentage of smokers and of those in the older age groups. Intake of vitamin C from potatoes and chips (fried potatoes) was uniform across categories; while the determinants of optimal versus low status were the intakes of citrus fruit, non-citrus fruit and fruit juice. Optimal status was achieved by a combined frequency of fruit, vegetables and/or fruit juice of three times a day or more except in older male smokers where a frequency greater than this was required even to reach a marginal plasma vitamin C level. CONCLUSION: Fruit, vegetables and/or fruit juice three or more times a day increases plasma vitamin C concentrations above the threshold for risk of deficiency.

The dietary habits of 11-12 year-old children in two Tayside secondary schools--comparison with the targets set by the Scottish Diet Report.

The diets of over 300 children in their first year at two Tayside secondary schools were assessed using a simplified food frequency questionnaire. Results were compared with the recent targets (Scottish Diet Report 1993) set for children for the year 2005. It was estimated that only six (< 2%) of the 331 children achieved all of the first five targets, namely 3-4 portions of vegetables and fruit per day; whole grain or granary bread or cereals twice daily; semi-skimmed milk; fish twice weekly; and meat products less than twice weekly. In addition, less than 5% achieved a Healthy Food Choice score (devised by the authors) commensurate with a healthy diet containing daily fruit and vegetables, semi-skimmed milk, wholemeal or similar bread or cereals, and fish at least once a week.