The Impact of Delayed Processing of Chilled Whole Blood Specimens on the Measurement of Nutritional Biomarkers in the United Kingdom National Diet and Nutrition Survey Rolling Programme.

BACKGROUND: The logistics of timely processing of blood specimens remains a barrier in population health studies to the generation of micronutrient status data. OBJECTIVES: To test a blood specimen processing protocol that includes overnight postage with cooling and its effect on nutritional biomarker concentrations. METHODS: This study was embedded within the United Kingdom National Diet and Nutrition Survey. Paired specimens were collected from 64 participants (16 y+). One set of specimens were processed within 2 h of collection ["field"] and paired samples were mailed in an insulated box with cold packs using an overnight postal service to a central laboratory ["postal"]. Specimen processing protocols were aligned across field sites and the central laboratory. Specimens were frozen and later analyzed using established methods for vitamins, minerals, lipids, ferritin, and C-reactive protein (CRP). Percent difference was calculated between protocols and compared with quality specifications determined from intra- and interindividual variation. RESULTS: In the postal protocol, ferritin [geometric mean percent difference (95% confidence interval)] [6% (3, 8)] (P = 0.002) and zinc [4% (1, 6)] (P = 0.004) were higher compared with the field protocol. Retinol [-3% (-4, -1)] (P < 0.0001) and selenium [-3% (-5, -1)] (P = 0.003) concentrations were lower in the postal protocol, whereas total [2% (1, 3)] and HDL [4% (2, 5)] cholesterol were higher (P < 0.0001) than in the field protocol. Percent differences were within the optimum quality specification for the majority of biomarkers, but ferritin, zinc, and selenium fell outside of the optimum limits. Higher ferritin concentration in the postal protocol led to a decrease in the proportion of specimens with ferritin concentration <15 µg/L from 13% to 9%. CONCLUSIONS: The majority of micronutrient biomarkers, serum lipids, and CRP were minimally affected by delayed processing when cooled. The study suggests acceptable stability of nutritional biomarkers within the described protocol, which can provide accurate data for nutritional biomarkers commonly measured in studies and surveys.

Patterns of sociodemographic and food practice characteristics in relation to fruit and vegetable consumption in children: results from the U.K. National Diet and Nutrition Survey Rolling Programme (2008-2010).

OBJECTIVE: Few studies have considered the combined effects of home-related determinants on children's diet. The present study investigated independent associations between sociodemographic and food practice (SFP) characteristics and fruit and vegetable consumption in U.K. children and the combined effects of SFP on consumption using pattern analysis. DESIGN: Diet was assessed using 4 d food diaries, SFP were collected using computer-assisted personal interview. Linear regressions were used to test associations; principal component analysis was used to identify patterns of SFP characteristics. Regression of fruit (g/d) and vegetables (g/d) v. component scores of each pattern were performed. SETTING: U.K. National Diet and Nutrition Survey Rolling Programme (2008­2010). SUBJECTS: Children aged 1.5­10 years (n 642). RESULTS: Significant associations were found between fruit and vegetable consumption and household socio-economic status. Pattern 1, which was positively correlated with household structure characteristics, was associated with increased fruit consumption (P < 0.001). Pattern 2, characterised by positive correlations for socio-economic status, fruit availability and organic food purchase, and negatively correlated with household size and the number of children per household, was associated with higher fruit and vegetable consumption (both P < 0.001). Pattern 3, characterised by high frequency of eating out and eating takeaway, was associated with a lower consumption of both fruit (P < 0.012) and vegetables (P < 0.023). CONCLUSIONS: Patterns of SFP determinants may be more informative than individual characteristics in relation to dietary outcomes. Results have public health implications on the healthfulness of meals eaten out of home and in takeaways, as well as the need to reduce diet inequality in larger households with lower socio-economic status.

Assessing eating context and fruit and vegetable consumption in children: new methods using food diaries in the UK National Diet and Nutrition Survey Rolling Programme.

BACKGROUND: Eating context is the immediate environment of each eating occasion (EO). There is limited knowledge on the effects of the eating context on food consumption in children, due to the difficulty in measuring the multiple eating contexts children experience throughout the day. This study applied ecological momentary assessment using food diaries to explore the relationships between eating context and fruit and vegetable consumption in UK children. METHODS: Using 4 d unweighed food diaries, data were collected for 642 children aged 1.5-10y in two years of the UK National Diet and Nutrition Survey (2008-2010). Participants recorded all foods and drinks consumed at each EO, where and with whom the food was consumed, whether the TV was on and if eaten at a table. Mixed logistic regression and mixed multinomial logistic regression were used to calculate associations between eating contexts and fruit and vegetables (FV) consumed by quartiles. RESULTS: Of 16,840 EOs, 73% took place at home and 31% with parents only. Frequency of eating alone and with friends increased with age. Compared to eating at home, children aged 1.5-3y were more likely to consume fruit at care outside home (>10-50g OR:2.39; >50-100g OR:2.12); children aged 4-6y were more likely to consume fruit (>50-100g OR:3.53; >100g OR:1.88) and vegetables at school (>30-60g OR:3.56). Compared to eating with parents only, children aged 1.5-3y were more likely to consume fruit with friends (>10-50g OR:2.69; >50-100g OR:3.49), and with carer and other children/others (>10-50g OR:2.25); children aged 4-6y were more likely to consume fruit (>50-100g OR:1.96) and vegetables with friends (>30-60g OR:3.56). Children of all ages were more likely to eat vegetables when the TV was off than on and at a table than not at table. CONCLUSIONS: The use of food diaries to capture multiple eating contexts and detailed fruit and vegetable consumption data was demonstrated at a population level. Higher odds of FV consumption were seen from structured settings such as school and care outside home than at home, as well as when eating at a table and the TV off. This study highlights eating contexts where provision of fruit and vegetables could be improved, especially at home. Future research should take eating context into consideration when planning interventions to target children's food consumption and eating behaviour.

National Diet and Nutrition Survey: fat and fatty acid intake from the first year of the rolling programme and comparison with previous surveys.

High saturated fat intake is an established risk factor for several chronic diseases. The objective of the present study is to report dietary intakes and main food sources of fat and fatty acids (FA) from the first year of the National Diet and Nutrition Survey (NDNS) rolling programme in the UK. Dietary data were collected using 4 d estimated food diaries (n 896) and compared with dietary reference values (DRV) and previous NDNS results. Total fat provided 34-36 % food energy (FE) across all age groups, which was similar to previous surveys for adults. Men (19-64 years) and older girls (11-18 years) had mean intakes just above the DRV, while all other groups had mean total fat intakes of < 35 % FE. SFA intakes were lower compared with previous surveys, ranging from 13 to 15 % FE, but still above the DRV. Mean MUFA intakes were 12·5 % FE for adults and children aged 4-18 years and all were below the DRV. Mean n-3 PUFA intake represented 0·7-1·1 % FE. Compared with previous survey data, the direction of change for n-3 PUFA was upwards for all age groups, although the differences in absolute terms were very small. Trans-FA intakes were lower than in previous NDNS and were less than 2 g/d for all age groups, representing 0·8 % FE and lower than the DRV in all age groups. In conclusion, dietary intake of fat and FA is moving towards recommended levels for the UK population. However, there remains room for considerable further improvement.

National Diet and Nutrition Survey: UK food consumption and nutrient intakes from the first year of the rolling programme and comparisons with previous surveys.

The National Diet and Nutrition Survey (NDNS) is a cross-sectional survey designed to gather data representative of the UK population on food consumption, nutrient intakes and nutritional status. The objectives of the present paper were to identify and describe food consumption and nutrient intakes in the UK from the first year of the NDNS rolling programme (2008-09) and compare these with the 2000-01 NDNS of adults aged 19-64 years and the 1997 NDNS of young people aged 4-18 years. Differences in median daily food consumption and nutrient intakes between the surveys were compared by sex and age group (4-10 years, 11-18 years and 19-64 years). There were no changes in energy, total fat or carbohydrate intakes between the surveys. Children aged 4-10 years had significantly lower consumption of soft drinks (not low calorie), crisps and savoury snacks and chocolate confectionery in 2008-09 than in 1997 (all P < 0·0001). The percentage contribution of non-milk extrinsic sugars to food energy was also significantly lower than in 1997 in children aged 4-10 years (P < 0·0001), contributing 13·7-14·6 % in 2008-09 compared with 16·8 % in 1997. These changes were not as marked in older children and there were no changes in these foods and nutrients in adults. There was still a substantial proportion (46 %) of girls aged 11-18 years and women aged 19-64 years (21 %) with mean daily Fe intakes below the lower reference nutrient intake. Since previous surveys there have been some positive changes in intakes especially in younger children. However, further attention is required in other groups, in particular adolescent girls.