Diet after Liver Transplant: Dietary Patterns, Potential Determinants, and Interventions to Reduce Cardiovascular Risk

Background Liver transplantation is a treatment for end-stage liver disease with a 64% 10-year survival rate. Patients initially follow a high-protein, energy-dense diet to support recovery, with later recommendations for a healthy diet and physical activity. The ability of recipients to adopt healthy eating habits and the best support strategies remain unclear, with no liver transplant-specific guidelines. Given the high prevalence of diet-related conditions post-transplant, targeted dietary interventions are needed. According to Medical Research Council guidance, diet-related interventions should be theory-driven, outlining key components, mechanisms, and contextual factors. This thesis aims to build an evidence base for future development of interventions that promote healthy dietary behaviour after liver transplantation. Thesis aims For liver transplant recipients: • Examine dietary patterns. • Identify potentially modifiable factors that influence dietary behaviours. • Review and synthesise evidence from randomised controlled trials of the effectiveness of diet and physical activity interventions for improving cardiovascular risk factors. • Evaluate the Capability Opportunity Motivation Behavioural (COM-B) model to guide diet interventions. Methods and results In my first study, I conducted a systematic review and meta-analysis of studies of nutritional intake and dietary determinants in liver transplant recipients. The findings suggested that early post-transplant energy and protein needs were likely unmet, while long-term diets included high fat intake and low consumption of fibre, fruits, and vegetables. Evidence on overall diet quality and potential determinants of diet was limited. In my second study, I measured dietary intake, blood carotenoids, and diet determinants at baseline and six months later in 86 liver transplant recipients six months to three years post-transplant. Most participants did not meet healthy eating guidelines according to the Eatwell Guide and relative Mediterranean Diet Score. Multivariable regression identified several factors associated with the Mediterranean diet score. Enjoyment of food and age at completion of full-time education were positively associated, while food fussiness, satiety responsiveness, and abnormal liver function tests were negatively associated. Total carotenoids were positively associated with physical activity, while steroid use was linked to lower carotenoid levels. In my third study, I conducted semi-structured interviews with 13 liver transplant recipients to explore barriers and facilitators to adherence to diet and physical activity advice. Participants faced challenges in adapting to dietary and physical activity recommendations, with confidence and motivation fluctuating throughout recovery. Early post-transplant, fear and uncertainty were common, while encouragement and goal-setting improved engagement. Tailored, clear, and timely healthcare support facilitated progress, whereas inconsistent or vague advice created barriers. Social influences, including family, friends, and other transplant recipients, had an important role. Symptoms, medication side effects, and comorbidities often hindered behaviour change, though some conditions, like diabetes, motivated healthier choices. Environmental factors, such as hospital constraints and home recovery conditions, affected engagement in recommended behaviours. Emotional coping strategies and the drive to regain normalcy influenced long-term adherence. My final study was a systematic review and meta-analysis of randomised controlled trials of diet and physical activity interventions on cardiovascular risk in liver transplant recipients. Physical activity and combined diet and physical activity interventions did not significantly reduce weight or BMI but did lower body fat and triglycerides compared to control groups. However, the quality of evidence was low, and intervention descriptions were limited. Finally, I brought together all thesis findings to explain how they address the thesis aims. I demonstrated that the COM-B model is a useful theory to inform the development of diet interventions in combination with the Common-Sense Model of Illness Self-Regulation, which helps to understand why liver transplant recipients engage (or fail to engage) in healthy behaviours. Conclusions Improved dietary behaviours are needed to optimise long-term health of liver transplant recipients. Targeted interventions and tailored dietary guidelines have the potential to support this. Findings from my thesis provide a foundation for intervention development and further investigation. The COM-B model in combination with the Common-Sense Model of Illness Self-Regulation provides a valuable behavioural framework for guiding intervention design.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2025

Author dc:creator

• Spillman, Lynsey

Advisors dc:contributor.advisor

• Griffin, Simon
• Rennie, Kirsten
• Oude Griep, Linda

• Nutrition
• Diet
• Liver Transplant

Licence

• https://www.repository.cam.ac.uk/bitstreams/3e8f5813-f6be-4ca1-a120-e720acd9658a/download
• http://purl.org/NET/rdflicense/allrightsreserved

Language dc:language

eng

Author Identifier

0000-0003-1409-0273

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/391808