Functional foods containing probiotics have gained considerable attention due to their ability to improve the nutritional quality and health-promoting effects of food products. Probiotics, which are live microorganisms that confer health benefits when consumed in sufficient amounts, can enhance the bioavailability of nutrients through diverse mechanisms. Recent studies indicate that certain probiotic strains can produce essential vitamins, including B-complex vitamins and vitamin K, facilitate mineral absorption by lowering intestinal pH and breaking down antinutritional compounds such as phytates, and convert complex phenolic compounds into more bioactive and readily absorbable forms. These processes are driven by enzymatic activities, shifts in gut microbial populations, and the generation of short-chain fatty acids. This review examines the metabolic pathways involved in vitamin synthesis, mineral solubilization, and phenolic compound transformation by probiotics, providing updated insights into their nutritional and functional potential. Incorporating selected probiotic strains into food products represents a promising strategy to combat nutrient deficiencies and support health, while understanding the underlying molecular mechanisms and optimizing strain selection are essential for developing next-generation functional foods with superior nutritional and therapeutic properties.