A high-protein diet, not isolated BCAA, is associated with skeletal muscle mass index in patients with gastrointestinal cancer.

Objectives: Patients with cancer are susceptible to experiencing the loss of skeletal muscle mass. Thus, the purpose of this study was to evaluate whether a high-protein diet (HPD) or isolated branched-chain amino acid (BCAA) intake is associated with an increased skeletal muscle mass index (SMI) in patients with cancer of the gastrointestinal tract. Methods: This cross-sectional, observational study included 106 patients with gastrointestinal tract tumors. Food consumption was estimated using 24-h food recall. Patients were divided into two groups: a low-protein diet (LPD) group (≤1.2 g · kg · d-1) and a high-protein diet (HPD) group (>1.2 g · kg · d-1). Appendicular muscle mass (ASM) was calculated using Lee's formula, and its values were divided by the square of the height of the patient to obtain SMI values. Differences were considered significant when the probability they occurred by chance was <5% (P < 0.05). Results: Of 106 patients assessed, 69 (65%) consumed a diet consistent with specifications of the LPD group and 37 (35%) consumed a diet consistent with HPD intake. Logistic regression after adjusting for sex and caloric and carbohydrate consumption showed an association between SMI and HPD (odds ratio, 4.19; 95% confidence interval, 1.06-16.56; P < 0.001) but not with BCAA. Daily total protein intake, but not isolated BCAA or leucine, was able to predict an increase in SMI in 43% of patients considered (P = 0.006). Thus, HPD was associated with SMI, and total protein intake was a better predictor of SMI than BCAAs. Conclusion: HPD is a cost-effective way to enhance SMI, rather than focusing on the ingestion of isolated BCAAs.