Food group intake and chemotherapy-induced toxicity: a scoping review

This scoping review aimed to map the existing evidence on the associations between habitual food group intake and chemotherapy-induced toxicity and to identify critical gaps in the literature.

PubMed, Europe PMC, and OpenAlex were searched through March 2026 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews framework. Studies were classified into five tiers based on dietary specificity. An evidence gap map was constructed across food group categories and toxicity domains.

Of 31 eligible studies, only 4 evaluated food group-level associations with specific chemotherapy toxicities, focusing predominantly on chemotherapy-induced peripheral neuropathy (CIPN) in breast and colorectal cancer. Across these four studies, a few isolated associations emerged: of higher fish/seafood intake with lower odds of CIPN and of refined-grain and milk intake with higher odds of toxicity, each reported by a single study; egg intake showed divergent associations (lower odds of CIPN in one study but higher odds of hematologic toxicity in another). These associations are exploratory, as several studies assessed diet during or after treatment. No studies examined oral toxicities (mucositis and dysgeusia). No evidence existed for fermented vegetables or culturally specific food groups. Diet was assessed before chemotherapy initiation in only 2 studies. Among the 17 studies in which diet-toxicity associations were analyzed, energy adjustment was applied in only 8.

Food group-level observational evidence on chemotherapy toxicity is virtually absent, with critical methodological gaps across toxicity domains, dietary assessment timing, and population diversity. The available evidence is insufficient to support toxicity-specific dietary recommendations at the food-group level. The findings highlight the need for comprehensive prospective studies examining habitual dietary intake at the food group level across multiple toxicity outcomes, cancer types, and cultural contexts.