README: Chapter 3 – Modelling Vitamin C Intake and Status Using NDNS Data
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Thesis Title:
An Investigation of Overlooked Complexities Affecting UK Vitamin C Security and the Potential for Local Crops to Address Insecurities: A Case of UK Strawberries

Author: David Fisher  
Supervisors: Eleftheria Stavridou | Jenny Baverstock | Guy Poppy  
Date: 24/06/2025  
Contact:  
- D.Fisher@soton.ac.uk  
- eleftheria.stavridou@niab.com  
- J.Baverstock@soton.ac.uk  

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Description
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Chapter 3 examines vitamin C intake and biological status across the UK population using safeguarded secondary data from the National Diet and Nutrition Survey (NDNS). Statistical models are used to explore associations between intake levels, blood serum concentrations, and demographic or lifestyle variables. The chapter identifies factors that contribute to increased risk of vitamin C insecurity across population groups.

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File Structure
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chapter-03/
│
├── code/                       ← All code is accessible via the UK Data Service (see below)
│
└── data/
    ├── primary/                ← No primary data used in Chapter 3
    ├── processed/              ← All data are stored externally via the UK Data Service
    └── dictionaries/           ← No data files in this repository

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Code: ./code/
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All annotated R scripts used to process the safeguarded NDNS datasets are available via the UK Data Service:

- **Title**: Southampton Nutrient Analysis Group  
- **Project ID**: 274856  
- **Link**: https://ukdataservice.ac.uk/

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Data: ./data/processed/
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All processed datasets for Chapter 3 are accessible through the UK Data Service:

- **Title**: Southampton Nutrient Analysis Group  
- **Project ID**: 274856  
- **Link**: https://ukdataservice.ac.uk/

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Secondary Data Sources
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- **Bates et al., 2019**  
  *National Diet and Nutrition Survey: Years 1 to 9 of the rolling programme (2008/2009 – 2016/2017): Time trend and income analysis.*  
  Public Health England  
  https://www.gov.uk/government/statistics/ndns-time-trend-and-income-analyses-for-years-1-to-9  
  Accessed: 24/06/2025

- **Bates et al., 2020**  
  *National Diet and Nutrition Survey rolling programme years 9 to 11 (2016/2017 to 2018/2019).*  
  Public Health England  
  https://www.gov.uk/government/statistics/ndns-results-from-years-9-to-11-2016-to-2017-and-2018-to-2019  
  Accessed: 24/06/2025

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Usage Notes
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- All analyses in Chapter 3 are derived from safeguarded secondary datasets available via the UK Data Service.
- Researchers must be registered with an approved academic institution and agree to the End User Licence (EUL) to access NDNS data.
- All code and processed data are hosted externally under the **Southampton Nutrient Analysis Group** (Project ID: 274856).
- For access instructions, visit https://ukdataservice.ac.uk/ or contact the authors for further guidance.
- All figures used in Chapter 3 are included in the thesis and can be reproduced using the original scripts provided through the UK Data Service.

