Karen L. Barton

Estimation of typical food portion sizes for children of different ages in Great Britain

It is often the case in dietary assessment that it is not practicable to weigh individual intakes of foods eaten. The aim of the work described was to estimate typical food portion weights for children of different ages. Using the data available from the British National Diet and Nutrition Surveys of children aged 1 1/2-4 1/2 years (1992-1993) and young people aged 4-18 years (1997), descriptive statistics were obtained, and predicted weights were calculated by linear, quadratic and exponential regression for each age group. Following comparison of energy and nutrient intakes calculated from actual (from an earlier weighed intake study) and estimated portion weights, the final list of typical portion sizes was based on median portion weights for the 1-3- and 4-6-year age groups, and age-adjusted means using linear regression for the 7-10-, 11-14- and 15-18-year age groups. The number of foods recorded by fifty or more children was 133 for each of the younger age groups (1-3 and 4-6 years) and seventy-five for each of the older age groups. The food portion weights covered all food groups. All portion sizes increased with age with the exception of milk in tea or coffee. The present study draws on a unique source of weighed data on food portions of a large sample of children that is unlikely to be repeated and therefore provides the best possible estimates of childrens food portion sizes in the UK.

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.

Can the EPIC food-frequency questionnaire be used in adolescent populations?

OBJECTIVE To assess the validity of the food-frequency questionnaire used in the European Prospective Investigation of Cancer (EPIC FFQ) for estimating nutrient intake in an adolescent population. DESIGN Sixty-seven schoolchildren (mean age: 12.3 +/- 0.3 years) were recruited to complete a 7-day weighed dietary record (7-day WDR), the EPIC FFQ and supply one 24-hour urine collection. SETTING Harris Academy in Dundee (UK). RESULTS Fifty subjects completed both dietary assessment methods. Thirteen of these were classified as underreporters with energy intake/basal metabolic rate < 1.14. The EPIC FFQ showed higher estimates than the 7-day WDR for all nutrients. The median Spearman correlation coefficient for the nutrients examined was found to be 0.31 and increased to 0.48 after adjustment for total energy. The limits of agreement were as far apart as 13.4 MJ, 120 g, 270 g, 120 g and 1170 mg for energy, fat, sugar, protein and calcium, respectively. Correlations between urine and 7-day WDR dietary nitrogen and potassium were found to be statistically significant with r = 0.45 (P < 0.05) and r = 0.78 (P < 0.001) respectively. The median proportion of subjects that appeared in the same and opposite third of intake was found to be 45.9% and 10.8%, respectively. CONCLUSIONS The EPIC FFQ seems adequate to correctly classify low, medium and high consumers and might therefore be used to identify adolescent population groups at risk or for differences between populations. However, agreement between the EPIC FFQ and the 7-day WDR was very poor on both a group and an individual basis, and demonstrates that the EPIC FFQ is not an appropriate method for estimating absolute intakes in this age group.

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. Cronbachs 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.

Lowering of oxidative stress improves endothelial function in healthy subjects with habitually low intake of fruit and vegetables: A randomized controlled trial of antioxidant- and polyphenol-rich blackcurrant juice

Inadequate intake of the recommended five-a-day fruit and vegetable portions might contribute to increased cardiovascular disease risk. We assessed the effects of dietary intake of a blackcurrant juice drink, rich in vitamin C and polyphenols, on oxidative stress and vascular function. This was a double-blind, placebo-controlled, parallel group study of 66 healthy adults who habitually consume <2 portions of fruit and vegetables per day. Participants were randomly allocated to consume 250ml of placebo (flavored water) or low or high blackcurrant juice drink four times a day for 6 weeks. Flow-mediated dilation (FMD) and plasma concentrations of F2-isoprostanes and vitamin C were measured. In the high blackcurrant juice drink group FMD increased significantly (5.8±3.1 to 6.9±3.1%, P=0.022) compared with the placebo group (6.0±2.2 to 5.1±2.4%). Plasma vitamin C concentration increased significantly in the low (38.6±17.6 to 49.4±21.0µmol/L, P<0.001) and high (34.6±20.4 to 73.8±23.3µmol/L, P<0.001) blackcurrant juice drink groups compared with the placebo group (38.1±21.0 to 29.0±17.6µmol/L). F2-isoprostane concentrations were significantly lower in the high blackcurrant juice drink group (225±64pg/ml) compared with the low blackcurrant juice drink (257±69pg/ml, P=0.002) and placebo group (254±59pg/ml, P=0.003). At follow-up, changes in plasma vitamin C correlated significantly with changes in FMD (r=0.308, P=0.044). Consumption of blackcurrant juice drink high in vitamin C and polyphenols can decrease oxidative stress and improve vascular health in individuals with habitually low dietary fruit and vegetable intake.

Supporting postpartum weight loss in women living in deprived communities: design implications for a randomised control trial

Background/Objectives:Pregnancy is a life stage where excess weight gain may occur and the postpartum period is often characterised by weight retention. The aim of the current study was to evaluate the feasibility of undertaking a randomised controlled trial of a weight loss intervention (WeighWell) in postpartum women living in areas of social disadvantage.Subjects/Methods:The study aimed to recruit 60 women who were not pregnant, 6–18 months postpartum with a body mass index >25 kg/m2 living in areas of deprivation within Tayside, UK. Recruitment strategies focused on visits to community groups; writing directly to postpartum women living in areas of deprivation and primary care teams who covered the most deprived 15% of the population and advertising in community settings. The 12-week intervention used motivational interviewing techniques to promote an energy deficit diet and increased physical activity, delivered by three face-to-face consultations plus three structured telephone calls.Results:Of 142 women screened, 63 were eligible and 52 (83%) were recruited and randomised to an intervention (n=29) or comparison group (n=23). Over the 12-week intervention, body weight changed significantly by −1.6±2.0 kg in the intervention group compared with +0.2±2.2 kg in the comparison group, indicating the potential efficacy of the intervention. Loss to follow-up was 24% in the intervention group and 39% for the comparison group.Conclusions:The findings support the development of a definitive trial that embraces personalised recruitment strategies and the development of approaches to improve retention over a clinically relevant intervention period.

Increasing antioxidant intake from fruits and vegetables: practical strategies for the Scottish population

BACKGROUND Increasing intakes of dietary antioxidants may help to reduce oxidative damage caused by free radicals and provide protection against the progression of a number of chronic diseases. The present study aimed to estimate the antioxidant intake from fruits and vegetables in the UK and Scottish population and to examine consumption models to identify potential strategies to optimize antioxidant intake from these foods. METHODS This was a retrospective study of cross-sectional data on fruit and vegetable intake in relation to antioxidant intake. Antioxidant capacity of individual fruits and vegetables was determined by the ferric reducing antioxidant power assay and data on quantity and frequency of consumption of fruits and vegetables determined from National Diet and Nutrition Survey 2000-2001. RESULTS Mean antioxidant intake in UK population from fruits and vegetables varied by region. In the Scottish sample (n = 123), mean antioxidant intake was estimated at 680 +/- 689 micromol day(-1) with 92% subjects consuming <400 g of fruits and vegetables per day. Consumption data showed that strawberries, apples, orange citrus fruits, purple broccoli and cauliflower were the top five sources of antioxidants from fruits and vegetables in the Scottish population. CONCLUSIONS Appropriate selection of fruits and vegetables would help to achieve a higher antioxidant intake with the potential to produce significant health benefits.

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. Childrens 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 childrens 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.

Slow pace of dietary change in Scotland: 2001-9.

Monitoring changes in the food and nutrient intake of a nation is important for informing the design and evaluation of policy. Surveys of household food consumption have been carried out annually in the UK since 1940 and, despite some changes over the years 1940-2000, the method used for the Expenditure and Food Survey (Living Costs and Food Survey from 2008) has been fundamentally the same since 2001. Using these surveys an analytical procedure was devised to compare food consumption and nutrient intake in Scotland with the Scottish dietary targets, and monitor change. This method takes into account contributions to composite foods and losses due to food preparation, as well as inedible and edible waste. There were few consistent improvements in consumption of foods or nutrients targeted for change over the period 2001-9. A significant but small increase was seen in mean fruit and vegetable consumption (259 g/d in 2001, 279 g/d in 2009, equating to an increase of less than 3 g/person per year). There was also a significant decrease in the percentage of food energy from SFA (15·5 % in 2001, 15·1 % in 2009) and from non-milk extrinsic sugars (15·5 % in 2001, 14·8 % in 2009), concurrent with a reduction in whole milk consumption and soft drink consumption, respectively. These small changes are encouraging, but highlight the time taken for even modest changes in diet to occur. To achieve a significant impact on the health of the present Scottish population, the improvements in diet will need to be greater and more rapid.

Have food portion sizes increased in the UK over the last 20 years

Current published food portion sizes were estimated from data collected in the 1986–7 Dietary and Nutritional Survey of British Adults. However, there is evidence from the USA that portion sizes for specific foods, e.g. soft drinks, hamburgers and French fries, have increased over the last 20 years. Using the latest data available from the National Diet and Nutrition Surveys (NDNS) of adults aged 19–64 years, median portion weights were calculated and compared with those estimated from 1987 as average or medium portions in Food Portion Sizes and as the median portion deduced from the data given in A Photographic Atlas of Food Portion Sizes. In addition, a range of companies including food manufacturers, supermarkets and fast-food and restaurant chains were contacted and information on portion sizes obtained and compared with those collected in the 1990s. Of the fifty-seven average food portion sizes that could be directly compared, only six, all savoury items, showed an increased median size>5% of those reported earlier. In contrast, portion sizes had decreased or stayed the same for five types of potatoes or chips, nineteen fruits and vegetables and twelve dessert items.