"When the investigators examined the effects of these interventions on treatment tolerance, they found that whey protein isolate supplementation reduced the risk for any chemotherapy toxicity by 9.8% compared with nutritional counseling alone (95% CI, –16.9% to –2.6%; P=0.009). The risk for grade 3-4 toxicities, including hematologic and gastrointestinal malignancies, was 30% lower in the group supplemented with whey protein isolate (95% CI, –44.4% to 16.5%; P<0.001)."

https://www.clinicaloncology.com/Community-Oncology/Article/08-19/Whey-Protein-Boosts-Body-Weight-in-Malnourished-Cancer-Patients/55651