Sodium-dependent multivitamin transporter that mediates the electrogenic transport of pantothenate, biotin, lipoate and iodide (PubMed:10329687, PubMed:15561972, PubMed:19211916, PubMed:20980265, PubMed:21570947, PubMed:22015582, PubMed:25809983, PubMed:25971966, PubMed:27904971, PubMed:28052864, PubMed:31754459). Functions as a Na(+)-coupled substrate symporter where the stoichiometry of Na(+):substrate is 2:1, creating an electrochemical Na(+) gradient used as driving force for substrate uptake (PubMed:10329687, PubMed:20980265). Required for biotin and pantothenate uptake in the intestine across the brush border membrane (PubMed:19211916). Plays a role in the maintenance of intestinal mucosa integrity, by providing the gut mucosa with biotin (By similarity). Contributes to the luminal uptake of biotin and pantothenate into the brain across the blood-brain barrier (PubMed:25809983). {ECO:0000250|UniProtKB:Q5U4D8, ECO:0000269|PubMed:10329687, ECO:0000269|PubMed:15561972, ECO:0000269|PubMed:19211916, ECO:0000269|PubMed:20980265, ECO:0000269|PubMed:21570947, ECO:0000269|PubMed:22015582, ECO:0000269|PubMed:25809983, ECO:0000269|PubMed:25971966, ECO:0000269|PubMed:27904971, ECO:0000269|PubMed:28052864, ECO:0000269|PubMed:31754459}. This is the function of SLC5A6 (solute carrier family 5 member 6, ENSG00000138074).