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National Diet and Nutrition Survey
NDNS Reports and Data
NDNS data can be accessed from the UK Data Archive.
The National Diet and Nutrition Survey (NDNS) is designed to assess the dietary habits and nutritional status of adults and children in the UK. The survey is unique as it provides the only source of high quality data on dietary intake and nutritional status in a representative sample of the population. As such, NDNS gathers quantitative and qualitative information on the dietary habits and nutritional status of a representative sample of the UK population, comprising between 1000 and 1500 individuals per year. Adults and children aged 18 months and above are being recruited from England, Wales, Scotland and Northern Ireland. The Northern Ireland Statistics and Research Agency (NISRA) carry out interviews in Northern Ireland.
EWL Human Nutrition Research (EWL) provides the scientific lead for the NDNS RP and conducts the nutritional assessment and analysis for the survey, which is delivered by EWL in collaboration with NatCen Social Research and, for this period, the University College London Medical School.
Since 2008, the NDNS has been conducted as a cross-sectional Rolling Programme (RP) to enable more rapid data collection and greater ability to track temporal changes and to respond more quickly to changing policy needs. Prior to this, NDNS was carried out as a series of cross-sectional surveys in different age groups (see below).
The NDNS RP is funded by UK government health departments including Department of Health in England, Public Health England (PHE) and the Food Standards Agency (FSA). The programme is currently in its second funding phase: 2012-2017, fieldwork years 6-9.
The survey combines computer assisted personal interviews (CAPI) and self-completion questionnaires with an examination component. All survey components are carried out in the participant’s home. The survey is carried out in two stages, an interview visit followed by a nurse visit generally conducted around 8 – 12 weeks later.
The NDNS interview collects data on
- Demographic and socio-economic characteristics
- Dietary habits, food and nutrient intake and population trends in food consumption
- Physical activity
- Oral health
- General health and lifestyle
- A spot urine sample for iodine status assessment
The food intake data is collected using an estimated (unweighed) food diary.
The examination component consists of anthropometric and blood pressure measurements, and urine and blood collections for various laboratory tests. Clinical relevant results are reported back to the respondents themselves and/or their GP as requested on consent to participation.
Food intake data is collected using an estimated (unweighed) 4 day food diary. Participants are offered opportunity to receive feedback about their diet after completion of the nurse visit.
The nurse visit includes:
- anthropometric measurements
- blood pressure measurement
- blood sample collection for laboratory analysis for nutritional, routine metabolic and cardio-vascular status assessment
Clinically relevant results are reported back to the survey participants themselves and/or their GP in accordance with terms of consent.
The NDNS RP is carried out under National Research Ethics Service (NRES) Research Ethics Committee (REC) approval.
EWL’s role within the NDNS RP
MRC Elsie Widdowson Laboratory (EWL) provides the scientific lead for the NDNS RP and conducts the nutritional assessment and analysis for the survey. The survey is delivered in collaboration with NatCen Social Research (lead contractor) since the outset of the rolling programme, including the Surveys Team at UCL for NDNS RP Years 1 to 5.
Through the NSS programme and contribution of our Specialist Teams, EWL takes responsibility for all nutritionally-related inputs ranging from design and development, support for fieldwork, data and sample collection, through laboratory and data analysis, to interpretation and reporting of results. Currently in the second funding phase (years 6-9), EWL’s responsibilities to NDNS RP are as follows:
- Dietary assessment
- Fieldwork support and training and logistics support
- Blood and urine specimen logistics and analysis
- Management of the NDNS Biorepository
- Doubly-labelled-water logistics and analysis
- Data management
- Statistical analysis and reporting
The success of the NDNS depends on the good will and voluntary cooperation of members public across the UK to whom we are indebted. The survey is also reliant on the support of regional NHS and private laboratories for provision of blood specimen processing and storage and for specialist laboratories for provision of specific analytical measures outside the HNR repertoire.
Uses of the data
The NDNS data are used to assess the adequacy of food and nutrient intake and nutritional status in different population groups. They are also the major component of the evidence base to support work across the UK to facilitate the adoption of healthier eating in order to reduce diet-related disease. The NDNS RP is used by policy-makers in UK health departments to monitor progress against government targets and recommendations and progress on key diet and nutrition policy objectives. The NDNS also provides data to allow the Food Standards Agency (FSA) to carry out chemical exposure assessment as part of the government’s responsibilities for risk assessment and food safety.
Results from NDNS RP are published formally on a regular basis as government policy papers, prepared by EWL-NatCen. These reports provide an overview of dietary and nutritional status by age and sex group and detailed information about the survey and analytical methods used. Periodic reports also include comparison data, for example to past surveys (e.g. Year 1&2 combined report) and within NDNS RP (e.g. Year 1-4, publication pending).
Key publications include combined reports for Year 1&2 combined and Year 1, 2 and 3 combined. The Year 1 to 4 combined report is due for publication in 2014.
Policy papers from NDNS RP are available on the gov.uk website.
Key survey objectives:
- provide quantitative data on the food and nutrient intake, sources of nutrients, and nutritional status of the UK population
- describe the characteristics of individuals with intakes of specific nutrients that are above or below the national average
- monitor the extent to which the diets of population sub-groups vary from expert recommendations/dietary guidelines
- provide information on trends in food consumption, nutrient intake and nutritional status in different age groups
- measure blood and urine indices (dietary biomarkers) that provide an assessment of nutritional status, and to relate these to dietary, physiological and social data
- provide height, weight and other measurements of body size and examine their relationship to social, dietary, biochemical and health data
- assess physical activity levels
- provide information on oral health status in relation to diet and nutritional status
- provide data which will enable the calculation of likely dietary exposure to natural toxicants, contaminants, additives and other food chemicals for risk assessment
- EWL conducts additional investigations to explore the NDNS dataset in more detail to address issues of strategic importance for our research or on behalf of our collaborators. This may include the analysis of the diet or nutritional status of specific subgroups, examining the relationship between specific nutrients or foods on health outcomes and modelling the impact of reformulation or wider dietary change on the nation’s health.
The survey data are also a resource for further analyses and the biological specimen residues can provide a valuable starting point for further research studies, linked to the survey.
History of NDNS
EWL has a long history of involvement in NDNS and before that as MRC Dunn Nutrition Unit. Prior to moving to rolling programme format, the NDNS operated as a series of stand-alone cross-sectional surveys by age group:
- Children aged 1.5 – 4.5 y – fieldwork 1992-3
- People aged 65 + y – fieldwork 1994-5
- Young people aged 4-18 years – fieldwork 1997
- Adults aged 19-64 years – fieldwork 2000-1
A review commissioned by the Food Standards Agency (FSA) recommended moving to a rolling programme of surveys in order to be better able to track trends and to respond more quickly to changing policy needs. This was realized in 2006, when the FSA and the Department of Health commissioned the new NDNS rolling programme (phase I: 2008-2012).
UK Sodium (Salt) Surveys
The UK Sodium Surveys, funded by UK health departments, provide an assessment of dietary salt intake through the analysis of the sodium content of 24h urine samples collected from a representative sample of adults aged 19 to 64 years. These surveys are integral to the government’s public health surveillance programme, complementing the NDNS. HNR inputs include logistics support and fieldworker training for sample collection, laboratory analyses, results analysis, interpretation and reporting.
With our partner NatCen we are currently conducting Sodium Surveys for England and Scotland (2014/15). These will result in separate reports on sodium intakes for adults aged 19 to 64 years in England, Scotland and Northern Ireland. Publication is anticipated in 2015/16.
Recent completed Sodium Surveys with HNR involvement have included:
Past salt surveys: