An investigation of overlooked complexities affecting UK vitamin C security and the potential for local crops to address insecurities: a case of UK strawberries

Abstract

This thesis concerns a detailed assessment of the current state of vitamin C security in the United Kingdom. Vitamin C is essential for proper immune function, genetic regulation, and collagen synthesis, making its availability crucial for public health. Contemporary assessments indicate that the availability of vitamin C in the UK is heavily reliant on imported fruits and vegetables, leaving the country vulnerable to disruptions in global trade. However, there remains a gap in research regarding the accessibility, stability, and utilisation of vitamin C in the UK, which this thesis aimed to address. This thesis also asks to what extent could local food-based interventions contribute to increase vitamin C self-sufficiency.
Vitamin C accessibility, stability, and utilisation were examined through secondary analyses of nationally representative food purchase and dietary survey data. The risk of inadequate access to vitamin C was greatest in regions and households of lower socioeconomic status. Seasonal instabilities were also observed, with reduced household provisions and increased risk of inadequate intakes consistently occurring during the Autumn. Dose-response modelling showed that the vitamin C requirement to achieve adequate status was 73 mg/day, 1.8 times higher than the current recommended intake of 40 mg/day. Smokers and obese individuals were found to have attenuated utilisation of vitamin C, requiring intakes more than twice the amount compared to non-smokers and those of healthy weight.
The potential for local foods to enhance vitamin C self-sufficiency is explored through the case study of biofortified UK strawberries. An analytical survey of fresh strawberries available from UK grocery retailers found that vitamin C contents were 38% higher during the peak UK Summer production season (71 mg/100g) compared to the Winter when retailers were reliant on imported strawberries (52 mg/100g). Chapters 5 and 6 used experimental approaches to evaluate the potential to biofortify UK strawberries through agronomic interventions and selective breeding. Foliar fertiliser treatments were not found to influence vitamin C content, but did show positive effects on other parameters including selenium and berry sweetness. Selective breeding emerged as a promising strategy to increase vitamin C contents, with Elsanta (94 mg/100g) and Vibrant (91 mg/100g) strawberries containing 30-35% more vitamin C than the market leading genotype Malling Centenary (70 mg/100g).
The collective findings of this thesis highlight the need for targeted interventions to make vitamin C more accessible to population groups at risk of vitamin C insecurities. The case of biofortified strawberries highlights the potential for food-based interventions to enhance UK vitamin C security but emphasises the need for their integration into interdisciplinary strategies to effectively support the most vulnerable population groups.

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Identifiers

ORCID for David Fisher: orcid.org/0000-0002-7947-3366

ORCID for Jenny Baverstock: orcid.org/0000-0003-1777-2894

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