Dietary Intake and Cancer in Sub-Saharan Africa: A Critical Review of Epidemiological Studies

Cancer incidence is rising rapidly in Sub-Saharan Africa (SSA). Dietary intake is an established risk factor for certain cancers but only a few epidemiological studies have been conducted in SSA. This study systematically reviewed and summarized the published literature on this issue and identified gaps that can be addressed in future research. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and literature searched was conducted until 11/2/2021. Out of the 5,457 potential references, we reviewed 19 eligible studies: 17 case-controls, two cross-sectionals and no cohort study. South Africa and Kenya conducted the majorities of the studies. The commonest studied cancers were esophageal (9/19), colorectal (4/19) and breast (4/19). Only four studies utilized a validated Food Frequency Questionnaire (FFQ). Although most studies (16/19) reported associations between dietary intake and cancer risks, they were lacking important confounders including total energy intake, multivitamin intake, body fat measures, physical-activity, smoking, and alcohol. Despite rapidly expanding cases of cancer associated with diet, the existent evidence on diet-cancer relationship is too scarce to deduce solid conclusions. There is a need for large cohorts with comprehensive datasets, validated dietary instruments while using advanced statistical analyses that can provide further insights into the imperative links between African diet and cancer risk. Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2022.2032217 .