Effects of deficiency or supplementation of riboflavin on energy metabolism: a systematic review with preclinical studies

CONTEXT: Riboflavin (vitamin B2) is a water-soluble micronutrient considered to be a precursor of the nucleotides flavin adenine dinucleotide and flavin mononucleotide. This vitamin makes up mitochondrial complexes and participates as an enzymatic cofactor in several mechanisms associated with energy metabolism. OBJECTIVE: This systematic review collected and discussed the most relevant results on the role of riboflavin in the energy metabolism of lipids, proteins, and carbohydrates. DATA SOURCES: A systematic search was carried out in the PubMed-Medline, Scopus, Embase, and Web of Science databases using the PICOS (Population, Intervention, Comparison, Outcome, Study design) strategy. DATA EXTRACTION: The screening of studies went through 2 stages following predefined eligibility criteria. The information extracted covered reference details, study design, population characteristics, experimental model, treatment parameters and dosage, route of administration, duration of treatment, and results found. DATA ANALYSIS: The risk of bias was assessed using the SYRCLE Risk of Bias (RoB) tool for in vivo studies and the QUIN tool adapted for in vitro studies, utilizing 10 domains, including selection bias, performance bias, detection bias, attrition bias, reporting bias, and other biases, to evaluate the methodological quality of the included studies. CONCLUSION: This review concludes that riboflavin regulates energy metabolism by activating primary metabolic pathways and is involved in energy balance homeostasis.