aged 4 to 10 years
10.2 Comparison of NDNS RP Years 1 and 2 combined (Y1&2) with NDNS RP Years 3 and 4 combined
10.2.1 Background
This section compares dietary data from Y1&2 and Y3&4 of the NDNS RP. When comparing the data from Y1&2 with Y3&4 there are some important considerations to note. Firstly,
changes in nutrient intake over time can result from a change in patterns of food consumption or a change in the nutrient composition of a specific food or foods. The Department of Health’s
Nutrient Databank3 provides food composition data to support the estimation of nutrient intakes in the NDNS RP. Each survey year is analysed using a different version of the databank which is updated so that it best reflects the nutrient content of foods in that year. Updates aim to capture new food products to reflect foods available at the time of fieldwork data collection and to reflect reformulation of products (such as reductions in fat, sugar or salt content) and
changes in fortification practices for vitamins and minerals, (see Appendix A). It is important to note that changes in the databank are partly driven by the availability of new analytical data.
Such new data are produced only occasionally so a gradual change in the nutrient content of the food supply may appear as a step change in the nutrient databank and so in nutrient intakes. Therefore, observed changes in nutrient intake between Y1&2 and Y3&4 may be related to changes in nutrient composition reflected in the Nutrient Databank, rather than changes in actual nutrient intakes in the survey population over this period. A good example is trans fatty acids; new analytical data for trans fatty acids in processed foods4 was generated in 2010 and incorporated into the Year 3 databank so there appears to be a sharp drop in trans fatty acid intake between Y1&2 and Y3&4, whereas the fall in the trans fatty acid content of processed foods actually occurred over a longer timescale.
Secondly, as detailed in Chapter 5, section 5.1, weekend days were oversampled in Year 1 and this has led to a slightly higher proportion of weekend days and slightly lower proportion of weekdays in Y1&2 compared with Y3&4 (see Table 10A below), even though weekend days were under sampled in Year 2. As already described in Chapter 5, eating habits vary on different days of the week for some age groups; hence the unequal distribution of days
captured might impact on the comparisons presented in section 10.2. Alcohol consumption is likely to be particularly affected and therefore no comparison between Y1&2 and Y3&4 is made for alcohol.
Table 10A: Number of diary days by day of week (Y1&2 compared with Y3&4)
The statistical analysis in this section has been carried out to compare Y1&2 with Y3&4.
Results were tested at the 95% significance level. Statistically significant differences are highlighted in the tables. Some differences do not reach statistical significance due to small numbers in some groups. The following text focuses on statistically significant differences considered to be of public health interest rather than all of the statistically significant results.
10.2.2 Energy and macronutrient intake
This section presents key findings on the daily intakes of energy and macronutrients estimated from the food consumption data, comparing Y1&2 with Y3&4. Mean daily intakes of
macronutrients are also compared with the UK DRVs.1,5
With the exception of children aged 1.5 to 3 years, mean total daily energy intakes tended to be lower in all age/sex groups in Y3&4 compared with those in Y1&2. The differences were
significant for adults aged 19 to 64 years (1826 kcal per day in Y3&4 compared with 1896 kcal in Y1&2) and children aged 11 to 18 years (1735 kcal per day in Y3&4 compared with 1816 kcal in Y1&2).
Mean daily intakes of total fat for all age groups, except children aged 1.5 to 3 years, tended to be lower in Y3&4 compared with those in Y1&2. The differences were significant for men aged 19 to 64 years (75.3g compared with 80.1g per day), girls aged 4 to 10 years and 11 to 18 years and women aged 65 years and over (54.3g, 57.4g and 55.1g per day respectively compared with 57.8g, 62.3g and 60.1g per day respectively).
With the exception of children aged 1.5 to 3 years and boys aged 11 to 18 years, mean protein intakes tended to be slightly lower in Y3&4 compared with Y1&2. Mean protein intake in men aged 19 to 64 years was significantly lower in Y3&4 compared with Y1&2 (82.5g versus 87.7g per day).
Mean daily intakes of total carbohydrate tended to be similar between Y3&4 and Y1&2. Girls aged 11 to 18 years had a significantly lower mean intake of carbohydrate in Y3&4 compared with those in Y1&2 (204g versus 218g per day).
Expressed as a percentage of food energy, mean total fat intakes tended to be lower in Y3&4 compared with Y1&2. The differences were significant for boys aged 4 to 18 years (33.2%
versus 33.9%), men aged 19 to 64 years (34.3% versus 35.2%), girls aged 4 to 10 years (32.9% versus 34.2%) and women aged 65 years and over (34.0% versus 35.6%). No clear pattern was observed between Y3&4 and Y1&2 for protein intake as a percentage of food energy, although girls aged 11 to 18 years in Y3&4 had a significantly higher mean protein intake as a percentage of food energy compared with those in Y1&2 (15.1% versus 14.4%).
Carbohydrate as a percentage of food energy tended to be higher in Y3&4 compared with Y1&2 in most age groups and was significantly higher in men aged 19 to 64 years (48.5%
versus 47.1%), girls aged 4 to 10 years (52.8% versus 51.4%) and women aged 65 years and over (48.4% versus 46.8%).
Mean daily saturated fat intakes for all age/sex groups, in line with total fat intakes, also tended to be lower in Y3&4 compared with those in Y1&2, with significant differences observed in boys aged 4 to 10 years (22.1g versus 24.0g), men aged 19 to 64 years (27.4g versus 29.4g), girls aged 11 to 18 years (20.9g versus 22.5g) and women 65 years and over (21.4g versus 24.3g), In line with total fat, mean saturated fat intakes as a percentage of food energy tended to be slightly lower in Y3&4 compared with Y1&2 and were significantly lower in boys aged 4 to 10 years (12.7% versus 13.4%) and women aged 65 years and over (13.2% versus 14.3%).
Mean trans fatty acid intakes as a percentage of energy intake were significantly lower in Y3&4 compared with those in Y1&2 in all age/sex groups. This is likely to be due to changes in the trans fatty acid composition data used to calculate intakes.6 For example, in men aged 19 to 64 years in Y3&4, trans fatty acid intake contributed 0.5% to energy intake compared with 0.8% in Y1&2.
There were no significant differences in mean intakes of non-milk extrinsic sugars (NMES), either in absolute terms or as a percentage of energy in any of the age/sex groups. There was no consistent pattern of differences observed between Y3&4 and Y1&2 across the age groups.
Mean intakes of non-starch polysaccharides (NSP) were significantly higher in women aged 65 years and over in Y3&4 compared with Y1&2 (13.7g versus 12.5g). Mean intake of NSP for men aged 65 years and over was also slightly higher in Y3&4 compared with Y1&2 (15.2g versus 14.7g), although this did not reach statistical significance. In other age/sex groups intakes in Y3&4 were very similar to those in Y1&2.
(Tables 10.1a-10.1c)
10.2.3 Vitamins and minerals
This section presents daily intakes of selected vitamins and minerals, namely vitamin C, folate, iron and calcium, from foods only (excluding dietary supplements) for Y3&4 compared with Y1&2. Mean daily intakes of these vitamins and minerals are compared with the UK Reference Nutrient Intakes (RNIs)7 and the proportions of participants with intakes below the Lower Reference Nutrient Intakes (LRNIs)8 are shown. The RNIs and LRNIs for the vitamins and minerals presented are shown in Tables 5.14 and 5.32 (Chapter 5).
Mean daily iron intakes were similar in Y3&4 compared with Y1&2 in all age/sex groups. There was a higher proportion of girls aged 11 to 18 years with iron intakes below the LRNI in Y3&4 compared with Y1&2 (49% versus 43%) although this was not a significant difference.
No clear pattern of differences was observed in mean calcium intakes between Y3&4 and Y1&2. For girls aged 11 to 18 years and women aged 19 to 64 years, the proportion of participants with a daily calcium intake below the LRNI was significantly higher in Y3&4 compared with Y1&2 (23% and 10% versus 15% and 6% respectively).
Mean intakes of vitamin C were slightly lower in Y3&4 compared with Y1&2 for boys and girls aged 11 to 18 years, men and women aged 19 to 64 years and men aged 65 years and over although the differences did not reach statistical significance. Mean intakes were above the RNI
in both periods.
Mean daily folate intake was slightly lower in Y3&4 compared with Y1&2 for all age/sex groups except men aged 65 years and over and girls aged 4 to 10 years. This reached statistical significance for children aged 1.5 to 3 years, boys aged 4 to 10 years and adults aged 19 to 64 years (143μg, 194μg and 251μg versus 156μg, 209μg and 264μg respectively). For girls aged 11 to 18 years mean intake was 90% of the RNI in Y3&4 compared with 96% in Y1&2 and 9%
of girls were below the LRNI in Y3&4 compared with 7% in Y1&2. For women aged 19 to 64 years, the proportion of participants with a folate intake below the LRNI was significantly higher in Y3&4 compared with Y1&2 (5% versus 3%).
(Tables 10.3a-10.5c)
10.2.5 Vegetables, fruit, meat and fish consumption, including from composite dishes.
This section reports consumption of vegetables, fruit, meat and fish based on disaggregated data. This includes the contribution from composite dishes, but excludes the other components of those dishes.2 The number of portions of fruit and vegetables consumed per day has also been calculated from the disaggregated data in line with the “5-a-day” criteria, including up to one portion each of fruit juice and baked beans or pulses per day (see Appendix A).
No consistent pattern of differences between Y3&4 and Y1&2 was observed for mean total fruit and vegetable consumption (excluding fruit juice). The only significant difference was for boys aged 4 to 10 years in Y3&4 where mean consumption was 207g and significantly higher compared with Y1&2 (192g).
The mean number of portions of fruit and vegetables consumed, based on the “5-a-day”
criteria, tended to be slightly lower in boys aged 11 to 18 years and men aged 19 to 64 years in Y3&4 (2.8 and 3.9 portions respectively) compared with those in Y1&2 (3.1 and 4.3 portions respectively), although this did not reach statistical significance. No differences were seen for women or girls.
Mean consumption of total meat and red meat tended to be slightly lower in most age/sex groups in Y3&4 compared with Y1&2. Notably, in girls aged 4 to 10 years red meat
consumption was significantly lower in Y3&4 compared with Y1&2 (35g versus 46g). However,
in children aged 1.5 to 3 years mean red meat consumption was significantly higher in Y3&4 (33g) compared with Y1&2 (27g).
Overall, mean total fish and oily fish consumption was similar in all age/sex groups in Y3&4 compared with Y1&2.
(Tables 10.6a – 10.6c)