TABLE 1.
Effects of daily oral pyridoxine on plasma vitamin B-6 vitamer concentrations in humans1
| Dose, mg/d | Participants, n | Supplementation Period, wk | Plasma concentration, nmol/L | |||||
|---|---|---|---|---|---|---|---|---|
| Study2 | PL | PLP | PN | PNP | 4-PA | |||
| Edwards et al. (87) | 10 | 6 | 1 | 473 ± 333 | 595 ± 287 | ND | ND | 295 ± 104 |
| Edwards et al. (87) | 25 | 9 | 1 | 231 ± 157 | 631 ± 158 | ND | ND | 371 ± 175 |
| Edwards et al. (87) | 100 | 9 | 1 | 1277 ± 678 | 518 ± 130 | 268 | 350 ± 60 | 1239 ± 464 |
| Edwards et al. (87) | 200 | 9 | 1 | 2441 ± 904 | 623 ± 138 | 124 | 269 ± 213 | 2200 ± 633 |
| Edwards et al. (87) | 400 | 8 | 1 | 4764 ± 1664 | 732 ± 202 | 389 | 120 | 3717 ± 922 |
| Edwards et al. (87) | 800 | 7 | 1 | 9484 ± 1616 | 644 ± 182 | 4664 | 245 | 7085 ± 1528 |
| Bor et al. (88) | 40 | 43 | 12 | 700 | 350 | 100 | NM | 1200 |
| Vrolijk et al. (14) | 50 | 6 | 1 | 1200 | 400 | 400 | NM | NM |
| Speitling et al. (85) | 300 | 10 | 2 | 140 | 330 | ND | NM | 190 |
1
ND, not detected; NM, not measured; PL, pyridoxal; PLP, pyridoxal 5′-phosphate; PN, pyridoxine; PNP, pyridoxine 5′-phosphate; 4-PA, 4-pyridoxic acid.
2
In the Edwards et al. (87) study, values are means ± SDs for all vitamin B-6 vitamers except for PN with all doses and for PNP with 400 and 800 mg/d, where medians are used. In the other studies, values are means for all vitamin B-6 vitamers.