Whey protein isolate supplementation improves body composition, muscle strength, and treatment tolerance in malnourished advanced cancer patients undergoing chemotherapy

Randomized 1:1 trial in malnourished adults with advanced mixed-type cancer who were candidates for or already undergoing chemotherapy, were not receiving artificial nutrition, and had ECOG performance status =2. In the counseling + whey protein isolate arm, 82 participants were randomized.

Participants in the active arm received nutritional counseling plus two sachets per day of whey protein isolate (Prother; lipid- and lactose-free cow milk whey protein isolate) providing 20 g of protein daily. The supplement was taken for 3 months and mixed in water or foods. The comparator was nutritional counseling alone.

Whey protein isolate plus counseling was beneficial overall, improving cellular health, body composition, muscle strength, and chemotherapy tolerance over 3 months. Phase angle increased by 0.20b0 in the WPI group versus -0.28b0 in controls, with a mean difference of 0.48b0 (95% CI 0.05 to 0.90; P = .027). Standardized phase angle, FFMI (P = .041), body weight (P = .023), and handgrip strength (P < .001) also improved, while quality of life did not change significantly (P = .35). Chemotherapy toxicity was lower with WPI, including overall toxicity risk reduction (P = .009), fewer multiple toxicity events (P = .007), and fewer grade =3 events (P = .001; risk differences -9.8% and -30.4%). No apparent gastrointestinal intolerance was reported.

The intervention period was short at 3 months, so durability of benefit is unknown. The population was clinically heterogeneous, with multiple advanced cancer types, which limits cancer-specific interpretation and generalizability. The trial also provides limited evidence on quality of life and long-term safety, and the sample may be too small for subgroup inference.