The efficiency of vitamin C absorption varies with intake. At low to moderate doses, absorption is highly efficient, often exceeding 80%. However, as intake surpasses 200 mg per day, absorption efficiency diminishes due to transporter saturation, dropping to around 50% or less for doses above 1 gram. The excess, beyond the body’s utilization or storage capacity, is excreted in urine, highlighting the importance of regular intake rather than megadoses.
Several factors influence vitamin C absorption and bioavailability. Smoking, alcohol use, and chronic illnesses such as gastrointestinal disorders or kidney disease can impair absorption or increase the body's requirement. Similarly, aging reduces the efficiency of transporters. Dietary components also play a role; foods high in dietary fiber or calcium may marginally reduce absorption by binding with ascorbic acid. Conversely, pairing vitamin C with non-heme iron enhances the absorption of both, benefiting individuals with iron-deficiency anemia.
Recent studies have suggested potential benefits of liposomal vitamin C, which encapsulates the nutrient in lipid layers, enhancing its bioavailability. This delivery method might overcome some limitations of traditional supplementation, particularly for individuals with malabsorption issues. Additionally, emerging evidence highlights vitamin C's role in modulating gut microbiota, which may further influence its absorption and systemic effects.
Maintaining optimal vitamin C levels requires regular intake from fruits and vegetables like citrus, strawberries, bell peppers, and broccoli, or from supplements when necessary. A balanced approach ensures sufficient absorption and utilization to support immune resilience, skin health, and protection against oxidative damage. Preventing deficiencies, such as scurvy, and maximizing health benefits underscores the importance of this essential nutrient in human physiology.
Vitamin C Absorption: Key Processes and Influencing Factors
