Queuine: Bacterial-Derived tRNA Modifier as a Novel Nutrient for Human Health

Queuine (q), the free base form of queuosine (Q), is increasingly recognized as an essential micronutrient with potential “longevity vitamin” properties. This tRNA-modifying molecule enhances translational accuracy by fine-tuning wobble base pairing, thereby playing a fundamental role in maintaining protein conformational integrity and cellular homeostasis. Growing evidence links q deficiency to age-related disorders, cancer, and inflammation, yet the relationship between its dietary availability and human health remains incompletely understood. Building upon established knowledge of q’s chemical structure and biosynthesis, this review shifts the focus toward its role in mammalian physiology and nutrition. It provides a systematic synthesis of current understanding regarding q absorption, metabolism, and biological functions, critically examines the health implications of its deficiency, and profiles its presence in the food supply, thereby highlighting its dietary significance. Since humans lack the capacity for autonomous q synthesis, they depend on dietary intake and gut microbial production. Advances in q synthesis and purification technologies are also discussed. By elucidating the mechanisms of Q-modification and profiling q levels across food and microbial sources, this work highlights dietary q optimization as a promising food-based approach for health promotion, effectively connecting an evolutionarily conserved tRNA modification system with contemporary strategies in precision nutrition.