11/07/2026
Malnutrition is common in people undergoing cancer treatment, and it is frequently left uncorrected.
Surgery, chemotherapy, and radiotherapy raise the body's demand for protein at the same time that appetite, nausea, and difficulty eating drive intake down. The result is a shortfall that predicts a worse course: patients who enter treatment undernourished have more postoperative complications and longer hospital stays. A recent meta-analysis asked a direct question. If that protein gap is closed with an oral supplement, do outcomes actually change?
The analysis pooled 29 randomized controlled trials involving 2,279 patients with cancers of the gastrointestinal tract, lung, head and neck, liver, and breast, across surgical and non-surgical treatment. In each trial, patients received a high-protein oral nutritional supplement, defined as at least 20 percent of its energy from protein, on top of their normal diet. The average supplement delivered roughly 34 grams of protein and 580 kilocalories per day. The comparison group ate normally without it.
Across the trials that measured them, high-protein supplementation was associated with a 38 percent reduction in the odds of complications, a category that included infections, surgical complications, and toxicities related to chemotherapy and radiotherapy. Translated into absolute terms, that is approximately 101 fewer patients with a complication for every 1,000 treated, and a number-needed-to-treat of 12, meaning that for every twelve patients given the supplement, one avoided a complication they would otherwise have had. A subgroup of trials using formulas enriched with omega-3 fatty acids showed a similar benefit, with a 31 percent reduction in complication odds. Hospital stay was also shorter, by an average of about a quarter of a day.
Pooled across the trials that recorded them, there was no significant effect on mortality or on hospital readmissions. This is a meaningful boundary. The evidence supports high-protein oral nutrition as a way to reduce the complications and burden of treatment, not as a therapy that extends survival. Feeding a patient adequately improves the road through treatment; it does not, on this evidence, change whether they survive the cancer.
First, this meta-analysis was conducted and funded by manufacturers of oral nutritional supplements, which does not invalidate the pooled result but is a relevant conflict of interest that the reader should weigh. Second, the trials spanned several cancer types and treatment settings, and the authors note that the effect of nutritional support likely varies by cancer and by clinical context, so a single pooled figure smooths over real heterogeneity. The practical conclusion is narrow and well-supported. In cancer patients, whose protein requirements are elevated by illness and who are frequently underfed, correcting that deficit with a high-protein oral supplement measurably reduces complications and shortens hospital stays. It is a supportive-care intervention with a real and specific benefit.
Delsoglio et al., Front Nutr 2025
Gupta et al., Can J Surg 2021
