Vitamin C, an essential co-factor for at least eight enzymatic reactions, might also be involved in development or treatment of cancer, cardiovascular diseases, diabetes, and stroke.

Ascorbic acid, the reduced form of vitamin C is transported across epithelial barriers by the sodium dependent vitamin C transporters 1 (SVCT1). SVCT1 is encoded by SLC23A1 and mapped to 5q31. 2 [1, 2]. Recently, the pattern of common genetic variants has been characterized for both ascorbic acid transporters, SLC23A1 and SLC23A2, which share common intron/exon borders, are 58% similar in sequence across the coding region, but differ greatly in size and linkage disequilibrium patterns [3]. Here we characterize the genetic variation in the less constrained SLC23A1 gene in more detail and test for functional consequences. SLC23A1 is expressed in tissues critical for absorption and reabsorption of vitamin C (kidney, intestinal, and hepatic tissues)[4]. Therefore functional consequences of variations in SVCT1 would impact on dietary requirements and recommendations.