Nutritional biomarkers and micronutrient status in patients with type 2 diabetes in Africa: a scoping review

Background and rationale: Type 2 diabetes mellitus (T2DM) represents a critical public health challenge in Africa, where the number of affected adults is projected to rise from 24 million (2021) to 55 million by 2045. This burden is compounded by a high prevalence of micronutrient deficiencies (pooled prevalence: 45.30%; 95% CI: 40.35–50.30%), yet no scoping review has systematically mapped nutritional biomarker status across African T2DM populations. This review aims to fill this continental evidence gap. Objectives: To systematically map the available evidence on nutritional biomarker and micronutrient status (vitamin D, B12, magnesium, zinc, selenium, chromium, iron, folate, albumin, ferritin) in adult T2DM patients across Africa, with particular attention to underrepresented regions including North Africa and the Maghreb. Framework and reporting: This scoping review is conducted following the Arksey and O'Malley five-step framework and reported according to the PRISMA Extension for Scoping Reviews (PRISMA-ScR) 2018 guidelines. Search strategy: Six databases are searched: PubMed/MEDLINE, Scopus, Embase, Web of Science, Cochrane Library, and Google Scholar (January 2010 – March 2026). Search strings combine three semantic blocks: (1) nutritional biomarkers and micronutrients; (2) type 2 diabetes mellitus; (3) African geography, using both general terms and all 54 African country names to minimise indexing bias. Eligibility criteria: Population: Adult patients (≥18 years) diagnosed with T2DM Concept: Biological measurement of at least one nutritional biomarker or micronutrient Context: African countries (all 54) Study types: Observational studies, clinical trials, and reviews Language: No language restriction Period: January 2010 – March 2026 Study selection and data extraction: Two independent reviewers perform title/abstract and full-text screening using Rayyan (AI-assisted). Conflicts are resolved by consensus or a third reviewer. Status: Review in progress (screening phase).