Investigating the use of social media to improve calcium intake of young adults

Calcium intake is sub-optimal in the Australian population, particularly in adolescents and young adults. As this population are high users of social media, there is potential to use these platforms to encourage positive dietary behaviours. The overall aim of my PhD was to investigate the use of Facebook to improve calcium intake of young adults. Firstly, a secondary analysis was conducted of the NNPAS 2011-12 to examine patterns in calcium-rich foods and nutrients intake in the young adult Australian population. Calcium intake remains low in Australian adolescents and young adults, particularly in females; and a higher intake of calcium was associated with better diet quality. Next, a literature review assessed the efficacy of previous interventions to increase calcium intake and calcium-rich foods. Some evidence demonstrated that calcium and dairy interventions are effective, but the effect size was small and the pooled effect size was 0.35 (95% CI 0.04 to 0.67) for calcium and 0.31 (95% CI 0.11 to 0.50) for dairy. Focus groups were conducted with young adults to understand the psychosocial determinants and potential barriers to achieving adequate calcium intake. Then to design an intervention, a cross-sectional web-based survey examined the type of messaging preferred by young adults. The final phase was to design and conduct a three-arm randomised controlled trial with young adults. The CAlcium Nutrition-Dietary Opportunities (CAN-DO) study was developed using the COM-B theoretical framework and incorporated nine behaviour change techniques. This was the first intervention for improving calcium intakes of young adults using social media with text messages. The participants in the Facebook and text message group had improved knowledge about calcium (P= 0.0004) at six weeks. This thesis confirmed the feasibility and acceptability of the CAN-DO program. However, further research is needed to understand how to improve motivation to eat more calcium-rich foods