Optimizing Muscle Health in Patients with Colorectal Cancer through Targeted Nutrition Intervention
Creators: Ford, Katherine L
Publisher: name: University of Alberta Library
Year: 2022

<p>Patients with cancer are nutritionally vulnerable and at risk of low muscle mass (MM), a primary nutrition problem that independently predicts poor prognosis. Targeted nutrition interventions to optimize muscle health should focus on adequate energy and protein. Many patients alter their diet but may not consider the corresponding impact on muscle health.<br>
Three studies are presented as part of the Protein Recommendation to Increase Muscle (PRIMe) pilot trial. Patients newly diagnosed with stage II-IV colorectal cancer were randomized to a diet containing 1 g/kg/day) or a 2 g/kg/day protein for 12 weeks and supported with individualized nutrition counselling. Study 1 included baseline data to characterize total energy expenditure (TEE) and resting energy expenditure (REE) by calorimetry chamber of these patients. Energy expenditure was compared with energy intake recommendations and commonly used predictive equations. Predictors of TEE and REE were also investigated. <br>
Study 2 informed the feasibility of a diet containing 2 g/kg/day versus 1 g/kg/day of protein to halt MM loss (evaluated as appendicular lean soft tissue [ALST] index [ALSTI]) and assessed potential effects on maintaining physical function (Short Physical Performance Battery test). The feasibility of sustaining a 2 g/kg/day diet and the potential effects of the diets on anthropometrics, body composition, physical activity, energy expenditure, nutritional status, and quality of life were also assessed. <br>
Study 3 included baseline data that aimed to understand if and why dietary changes were made by patients. Patients’ beliefs pertaining to food intake post diagnosis and dietary changes that had the potential to impact muscle health were explored using audio-recorded one-on-one semi-structured interviews that were coded inductively and analyzed using qualitative content analysis. <br>
Study 1 included 31 patients (56±10 years; body mass index [BMI]: 27.9±5.5 kg/m2; 67.7% male; 74.2% stages II/III colon cancer). TEE (2074±337 kcal/day) did not differ from the lower recommended intake in cancer (25 kcal/kg/day) but was below the upper bound of 30 kcal/kg/day (-430±322 kcal/d; p&lt;0.001). TEE was variable (21-32 kcal/kg/day) and most patients (n=18) had TEE outside of the recommended intake range. REE was higher than predicted by the Mifflin-St. Jeor (145±144 kcal/day; p&lt;0.001) and Harris-Benedict (78±147 kcal/day; p=0.006) equations for the group. ALST, sex, rectal cancer, and presence of an ostomy were among predictors of TEE and REE. In models adjusted for sex, ALST and tumor location were independently predicted TEE (both p&lt;0.05). ALST independently predicted REE when adjusted for sex and tumor location (p&lt;0.001).<br>
Study 2 included 50 patients (57±11 years; BMI: 27.3±5.6 kg/m2; 60% males; 78% colon; 64% stage III). A 2 g/kg/day diet was not feasible (mean intake: 1.6±0.5 g/kg/day) although individually, 35.3% of patients (n=6) in this diet group attained 2.0 g/kg/day. This level of protein intake was observed in 8.7% of patients (n=2) in the 1 g/kg/day group. Difference between groups trended towards significance for MM (ALSTI 2 g/kg/day group: 8.2±1.8 kg/m2; 1 g/kg/day group: 7.2±1.2 kg/m2; mean difference: -0.9 kg/m2; 95% confidence interval: -1.9 to 0.1 kg/m2; p=0.065) but were not observed for physical function. Irrespective of diet allocation, a 1.0 g/kg/day increase in protein intake appeared to result in 1.6% increase in ALSTI (β: 1.572; 95% CI: -0.243, 3.387; p=0.090). Positive associations between protein intake and physical function and nutritional status scores were noted.<br>
Study 3 included 29 patients (57±10 years; 62% male; 59% stage III) who reported varied degrees of dietary change that stemmed from internal and external influences. Four main themes emerged to describe dietary decisions after diagnosis: (1) Medical Influences: eating to live; (2) Health Beliefs: connecting lived experiences with new realities; (3) Static Diets: no changes post-diagnosis; and (4) Navigating External Influences: confluence of personal agency and social constraints.<br>
Key findings of this thesis were that energy recommendations, which impact MM, are variable and not an all-encompassing approach to optimize muscle health in patients with cancer. We showed that increased protein intake through targeted nutrition intervention positively impacted muscle health but that a target of 2.0 g/kg/day was not feasible for patients. Prior to nutrition intervention, patients altered their dietary choices based on the degree to which dietary decisions provided a sense of control over physical ramifications of cancer. Overall, this research is a step towards designing definitive trials to assess targeted nutrition interventions to optimize muscle health in cancer.</p>