Abstract copyright UK Data Service and data collection copyright owner.The National Diet and Nutrition Survey (NDNS) Rolling Programme (RP) began in 2008 and is designed to assess the diet, nutrient intake and nutritional status of the general population aged 1.5 years and over living in private households in the UK. (For details of the previous NDNS series, which began in 1992, see the documentation for studies 3481, 4036, 4243 and 5140.)The programme is funded by Public Health England (PHE), an executive agency of the Department of Health, and the UK Food Standards Agency (FSA).The NDNS RP is currently carried out by a consortium comprising NatCen Social Research (NatCen) (NatCen, contract lead) and the MRC Epidemiology Unit, University of Cambridge (scientific lead). The MRC Epidemiology Unit joined the consortium in November 2017. Until December 2018, the consortium included the MRC Elsie Widdowson Laboratory, Cambridge (former scientific lead). In Years 1 to 5 (2008/09 – 2012/13) the consortium also included the University College London Medical School (UCL).Survey activities at the MRC Epidemiology Unit are delivered with the support of the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre (IS-BRC-1215- 20014), comprising the NIHR BRC Nutritional Biomarker Laboratory and NIHR BRC Dietary Assessment and Physical Activity Group. The NIHR Cambridge Biomedical Research Centre is a partnership between Cambridge University Hospitals NHS Foundation Trust and the University of Cambridge, funded by the NIHR. The NDNS RP provides the only source of high quality, nationally representative UK data on the types and quantities of foods consumed by individuals, from which estimates of nutrient intake for the population are derived. Results are used by Government to develop policy and monitor progress toward diet and nutrition objectives of UK Health Departments, for example work to tackle obesity and monitor progress towards a healthy, balanced diet as visually depicted in the Eatwell Guide. The NDNS RP provides an important source of evidence underpinning the Scientific Advisory Committee on Nutrition (SACN) work relating to national nutrition policy. The food consumption data are also used by the FSA to assess exposure to chemicals in food, as part of the risk assessment and communication process in response to a food emergency or to inform negotiations on setting regulatory limits for contaminants.Further information is available from the gov.uk National Diet and Nutrition Survey webpage.

Assessment of Dietary Sodium in Adults: The Assessment of Dietary Sodium is an add-on study to the NDNS RP, and is funded by Public Health England (PHE), an executive agency of the Department of Health, and the UK Food Standards Agency (FSA). It is carried out by a consortium comprising NatCen Social Research (NatCen) and MRC Elsie Widdowson Laboratory (MRC EWL), formerly known as MRC Human Nutrition Research (HNR). Fieldwork in Northern Ireland was carried out by fieldworkers from the University of Ulster. The Scientific Advisory Committee on Nutrition (SACN) recommend a target reduction in the average salt intake of the population to no more than 6g per day. This figure has been adopted by the UK government as the recommended maximum salt intake for adults and children aged 11 years and over. Following publication of the SACN report in 2003, the government began a programme of reformulation work with the food industry aimed at reducing the salt content of processed food products. Voluntary salt reduction targets were first set in 2006, and subsequently in 2009, 2011 and 2014, for a range of food categories that contribute the most to the population's salt intakes. Dietary salt intake can be assessed by measuring sodium excretion in urine. Since the level of sodium in urine fluctuates according to what was eaten at the last meal and how much fluid an individual has drunk, and because salt is the predominant source of sodium in the UK diet, a urine collection over 24 hours is accepted as being the most reliable method for assessing salt intake in the population. Eleven urinary sodium surveys of adults aged 19-64 years have been conducted (as part of the National Diet and Nutrition Survey Rolling Programme (NDNS RP) or as stand-alone surveys) between 2000 and 2015, some covering the UK as a whole and some in a single devolved country. The surveys are included in this dataset, as follows:England 2006 sodium survey of adults aged 19-64 yearsScotland 2006 sodium survey of adults aged 19-64 yearsWales 2007 sodium survey of adults aged 19-64 yearsUK 2008 sodium survey of adults aged 19-64 yearsScotland 2009 sodium survey of adults aged 19-64 yearsEngland 2011 sodium studyEngland 2014 sodium studyScotland sodium study 2014Northern Ireland sodium study 2015Further information can be found at the following webpages:An assessment of dietary sodium levels among adults (aged 19-64) in the general population, based on analysis of sodium in 24 hour urine samples, England 2005/06 (published October 2006)Assessment of dietary sodium levels in the general population, Scotland 2006 (originally published March 2007, revised May 2011)An assessment of dietary sodium levels among adults (aged 19-64) in the general population in Wales based on analysis of dietary sodium in 24 hour urine samples, 2006 (published February 2007)An assessment of dietary sodium levels among adults (aged 19-64) in the UK general population in 2008, based on analysis of dietary sodium in 24 hour urine samples(published June 2008)A survey of 24 hour urinary sodium excretion in a representative sample of the Scottish population as a measure of salt intake, 2009 (published April 2011)https://www.gov.uk/government/publications/assessment-of-dietary-sodium-levels-among-adults-aged-19-64-in-england-2011 https://www.gov.uk/government/statistics/national-diet-and-nutrition-survey-assessment-of-dietary-sodium-in-adults-in-england-2014http://www.foodstandards.gov.scot/national-diet-and-nutrition-survey-assessment-dietary-sodiumhttps://www.food.gov.uk/northern-ireland/nutritionni/national-diet-and-nutrition-survey-assessment-of-dietary-sodiumFor the second edition (May 2018) data and documentation for the 2006-2009 surveys have been added; the study originally covered 2011-2015. It should be noted, however, that not all UK countries are covered in all survey years.A later study, conducted in 2018-2019, is available under SN 8640.

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A 24-hour urine collection method was used as it is regarded as the gold-standard method of assessing salt intake in population surveys and was consistent with previous surveys. Since the level of sodium in urine fluctuates according to what was eaten at the last meal and how much fluid an individual has drunk, and because salt is the predominant source of sodium in the UK diet, a urine collection over 24 hours is accepted as being the most reliable method for assessing salt intake in the population. Results from an incomplete 24-hour urine collection are misleading because they do not reflect 24-hour intake. To be usable in the final analysis the 24-hour collection had to be complete, or within the range regarded as 'adjustable' which can be assessed by analysis of para-aminobenzoic acid (PABA) excretion.

Multi-stage stratified random sample

Face-to-face interview

Telephone interview

Clinical measurements