This thesis is a two paper thesis with part one being a systematic review and part two being a data analysis of mindfulness-based interventions on dietary treatment adherence through the mediation of self-regulatory processes. Paper 1: Objectives: The present study aimed to systematically evaluate the state of the evidence on the relationship of self-regulation (specifically self-related processing, cognitive processes, and emotion regulation) with heart healthy, evidence-based dietary patterns. A further aim is to determine if there are specific self-regulation processes that when modified in a randomized controlled trial, are associated with changes in dietary patterns. Methods: PubMed, EMBASE, CINAHL, and PsycInfo databases were systematically searched to identify randomized controlled trials published between January 1, 1995 and June 1, 2016. Studies with adult participants that displayed significant changes in a validated measure of self-regulation and analyzed one of four evidence-based diets associated with decreased heart disease risk (low-salt, low-calorie, Mediterranean Diet, or Dietary Approaches to Stop Hypertension Diet) were included for the review. Studies that were single armed, quasi-experimental, analyzed only components of the evidence- based diets (e.g. only fruits and vegetable consumption) were excluded from the review. Results: Of the 1,721 studies retrieved and screened in duplicate, 29 full-text articles were reviewed for inclusion. Of these, five studies with a combined total of 973 participants were included. In all five studies, a form of dietary self-efficacy was evaluated and found positive changes over the course of the intervention and follow-up. Only one study evaluated emotional eating and revealed nonsignificant differences between groups. Two studies evaluated low-caloric diets and three studies analyzed the Dietary Approaches to Stop Hypertension diet. All studies showed improvements in dietary patterns or components of diets. Associations between change in self-regulatory skills and change in dietary patterns were assessed in four of the five studies, with three finding significant positive associations. Conclusions: Although not all studies found associations between changes in all self- regulation skills and all evidence-based dietary pattern measures, each study revealed positive changes in dietary self-efficacy and diet. Results from the few studies that did incorporate self-regulatory skills into the intervention suggest that improving self- efficacy may mediate changes in dietary patterns. Paper 2: Objectives: The primary aim of this study was to investigate whether the Mindfulness- Based Blood Pressure Reduction (MB-BP) intervention influenced blood pressure- relevant dietary patterns, including the Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean diet. Secondary aims were to determine if self- regulatory processes, evaluated through the Difficulties in Emotion Regulation Scale (DERS) and the Multidimensional Assessment of Interoceptive Awareness (MAIA), were mechanisms by which MB-BP could alter dietary patterns. A further secondary aim was to investigate if those who were confident or motivated to change dietary patterns, versus those who were not, made more changes to their diet at 10-weeks follow-up. This study served as a pilot for a randomized control trial. Methods: Data were collected from eligible and consenting participants at baseline and 10 weeks from in-person interviews and at-home questionnaires. Student’s paired t-tests were used to assess the effects of the intervention on dietary patterns and self-regulation. Regression analyses evaluated if self-regulation measures were mediators for the change in dietary patterns. Subgroup analyses were performed on motivation and confidence to change diet and among those who had baseline controlled versus uncontrolled blood pressure. Results: A total of 49 participants consented and enrolled in the study. Mean age was 59.5 years. A majority of the participants were white (95.9%), and 61% were female. Compared to baseline, following completion of the MB-BP intervention, MAIA total scores increased by a mean of 3.90. The mean difference in the DERS total score and most component scores, in addition to overall diet scores for either Mediterranean diet or DASH diet did not change significantly. Among the components of each diet, sweets, eggs, and legumes dietary components changed significantly at follow-up. Those who were motivated and confident to change had no significant changes in their diet while those who were less confident or motivated to change had significant changes in overall DASH diet score and the sweets and egg dietary components. In mediation models, evidence suggested the self-processing domain assessed by MAIA, mediated the relationship between MB-BP and several diet outcomes including DASH diet sweets and Mediterranean diet egg components. Conclusions: Findings suggest that MB-BP may decrease the consumption of sweets, and eggs, and increase the consumption of legumes components. Furthermore, it may be successful in engaging and improving self-regulation among participants, specifically for those who are not very motivated or not very confident to change their diet. This change in self-regulation may be a useful method to improve the dietary intake of hypertensive participants
Northuis, Carin,
"The impact of self-regulatory processes on dietary intake and behavior change"
(2017).
Public Health Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z028062T
