Mashua (Tropaeolum tuberosum Ruiz & Pavón): Nutritional Composition, Bioactive Compounds, and Functional Potential as an Andean Natural Ingredient

<i>Mashua</i> (<i>Tropaeolum tuberosum</i>), an underutilized Andean tuber, has gained increasing scientific interest due to its exceptional nutritional composition and high bioactive phytochemical content. This narrative review synthesizes evidence from 68 peer-reviewed studies published up to August 2025, obtained through searches in Scopus and Web of Science, examining its macro- and micronutrient profile, richness in starch, proteins, and vitamin C, and diverse bioactive compounds, including glucosinolates, anthocyanins, and flavonoids. These metabolites exhibit strong antioxidant, anti-inflammatory, anticancer, and cardioprotective activities, with the highest concentrations being observed in purple and black morphotypes. Recent studies demonstrated that incorporating <i>mashua</i> into bakery, extruded, and fermented food formulations enhanced nutritional value and oxidative stability. Overall, <i>mashua</i> represents a promising natural ingredient for functional foods and nutritional applications. Further research is required to optimize processing conditions, improve the stability and bioavailability of its active compounds, and validate its health-promoting effects.