<![CDATA[Introduction: Head and neck cancer (HNC) patients are at high risk of malnutrition and functional decline. Protein and branched-chain amino acids (BCAA) are key nutrients for muscle protein synthesis and may influence functional capacity. This study examined the association between protein and BCAA intake and functional capacity in malnourished HNC patients receiving chemoradiotherapy. Methods: A cross-sectional study was conducted at a radiotherapy outpatient clinic among malnourished HNC patients undergoing chemoradiotherapy (week 4–5). Energy and protein intake were assessed using three non-consecutive 24-hour food recalls, while BCAA intake was estimated using a semi-quantitative FFQ. Functional capacity was evaluated using the six-minute walk test (6MWT). Associations were analyzed using Spearman’s correlation test. Results: A total of 94 participants were included (mean age 46.9 ± 11.9 years; 61.7% male), with most diagnosed at stage IV disease. Median protein intake was 40.65 g/day (0.79 g/kg BW/day), with 74.5% classified as having inadequate protein intake. Median total BCAA intake was 9.08 g/day. The mean 6MWT distance was 332.9 ± 123.9 m. Significant moderate positive correlations were found between protein intake and 6MWT distance (r = 0.444; p < 0.001) and between BCAA intake and 6MWT distance (r = 0.419; p < 0.001). Conclusion: Protein and BCAA intake showed a moderate association with functional capacity among malnourished HNC patients undergoing chemoradiotherapy. These findings support the importance of optimizing protein and BCAA intake to preserve functional status during active cancer treatment.]]>
