Research Information System
Nutrition, vol.143, 2026 (SCI-Expanded, Scopus)
Introduction Cancer-related malnutrition is common in gastrointestinal system (GIS) cancer patients, with oral nutritional supplements (ONS) prescribed to address deficiencies. This study assessed ONS-adherence rates in GIS cancer patients and their impact on nutritional status, body composition, functional outcomes, and quality of life. Material and Methods A prospective, multicenter study (ONMUS: Oral Nutritional Support Adherence, Muscle Strength, and General Health in Gastrointestinal Cancer Patients) was conducted across eight centers in Turkey, including 426 GIS cancer patients. Malnutrition was assessed with the Subjective Global Assessment, and eligible patients were consecutively recruited. ONS adherence (≥75% of prescribed ONS), anthropometry, body composition, handgrip strength, functional performance, and quality of life were recorded was monitored over three visits. Results The cohort included 426 malnourished patients (mean age 61.1 ± 11.2 y, range: 19 to 90; 36.4%—female, 63.6%—male). Cancer types were gastric (35.7%), colon (33.9%), and rectal (30.4%). Subjective Global Assessment-based severe malnutrition decreased by 39.8% in the ONS-adherent group (AG) versus 8.4% in the non-AG (NAG). Body mass index declined in the NAG ( P = 0.04), while weight and body mass index were maintained in the AG. Midupper arm and calf circumferences declined significantly in the NAG ( P ≤ 0.05). Handgrip strength increased by 2 kg only in the AG ( P = 0.003). ONS-adherence rates declined from 93.4% to 78.4% ( P < 0.001). Main reasons for non-adherence were appetite loss (5.2%), nausea (4.9%), and GI intolerance (2.8%). Conclusions Sustained ONS adherence improved muscle strength, body composition, and overall health in GIS cancer patients. Strategies to monitor and support adherence should be integrated into routine nutritional care.