StatPearls: Riboflavin DeficiencyStatPearls. StatPearls Publishing: Treasure Island (FL).BOOK
Riboflavin (vitamin B2) is a water-soluble, heat-stable vitamin essential for cellular energy metabolism, acting as a precursor to the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These cofactors are required by flavoproteins such as succinate dehydrogenase (Complex II), which participate in both the citric acid cycle and the mitochondrial electron transport chain, enabling adenosine triphosphate (ATP) production, maintaining redox balance, and supporting antioxidant defenses. Beyond energy metabolism, riboflavin contributes to immune function and to maintaining the health of skin, hair, and mucous membranes. Deficiency disrupts these pathways, leading to fatigue, normocytic anemia, neuromuscular symptoms, and secondary impairments in iron and other B-vitamin metabolism, including the activation of niacin (vitamin B3) and pyridoxine (vitamin B6). Because humans cannot synthesize riboflavin, adequate dietary intake is necessary, and absorption depends on normal gastrointestinal function. Excess riboflavin is excreted in urine, producing the characteristic yellow color that indicates adequate intake. Clinical deficiency is characterized by mucocutaneous manifestations (cheilosis, angular stomatitis, glossitis, dermatitis) and anemia; in severe or prolonged cases, it may lead to neurologic or ocular metabolic abnormalities, reduced physical performance, and developmental problems. Emerging evidence also links riboflavin deficiency to psoriasis, with decreased intake associated with a higher risk and upregulated riboflavin metabolism observed in psoriatic skin, suggesting a protective role for adequate riboflavin status, particularly in individuals older than 40 years. This article reviews the etiology, epidemiology, pathophysiology, clinical presentation, evaluation, management, complications, and prognosis of riboflavin deficiency. The article also highlights the roles of patient education and interprofessional healthcare team collaboration in optimizing patient outcomes.
