Daily and twice-daily administration of 60 mg Fe (studies 2 and 3)
| . | . | Iron bioavailability . | Iron status . | ||||
|---|---|---|---|---|---|---|---|
| . | Time and day of administration . | Fractional Fe absorption (%)† . | Fe absorbed (mg)† . | PHep (nM)† . | PF (µg/L)† . | sTfR (mg/L)‡ . | Body iron stores (mg/kg BW) ‡ . |
| Study 2: Daily* | 8:00 am, d1 | NA | NA | 0.6 (0.5-8.9) | 16.2 (13.5-23.0) | 4.4 (1.7) | 3.5 (2.7) |
| 8:00 am, d2 | 22.9 (10.5-49.4) | 13.8 (6.3-29.6) | 0.8 (0.4-6.1) | 15.5 (7.2-30.0) | 5.1 (1.3) | 2.7 (2.1) | |
| 8:00 am, d3 | 14.6 (7.2-28.3)§ | 8.8 (4.6-17.0)§ | 1.5 (0.3-8.5)‖ | 26.7 (11.6-57.5)¶ | 5 (1.5) | 4.7 (2.3)# | |
| 8:00 am, d15 | NA | NA | ND | 16.9 (7.3-34.0) | 5.1 (1.4) | 3.0 (1.7) | |
| Study 3: Twice daily* | 10:00 am, d1 | 17.1 (8.5-37.3) | 10.2 (5.1-22.4) | 0.9 (0.3-3.7) | 13.6 (7.1-32.0) | 4.9 (1.1) | 2.3 (2.2) |
| 4:00 pm, d2 | 12.5 (6.3-19.2)** | 7.5 (3.8-11.5)** | 4.1 (0.5-10.7)†† | 15.9 (6.1-37.5)‡‡ | 5.2 (1.3) | 2.5 (2.4) | |
| 8:00 am, d3 | 9.9 (4.4-16.3)** | 5.9 (2.6-9.8)** | 6.3 (1.3-14.1)††, § | 32.2 (19.3-57.8)a | 5.1 (1.4) | 5.2 (1.6)†† | |
| 8:00 am, d15 | NA | NA | ND | 16.4 (8.4-53.1) | 4.6 (0.9) | 3.2 (2.2) | |
| . | . | Iron bioavailability . | Iron status . | ||||
|---|---|---|---|---|---|---|---|
| . | Time and day of administration . | Fractional Fe absorption (%)† . | Fe absorbed (mg)† . | PHep (nM)† . | PF (µg/L)† . | sTfR (mg/L)‡ . | Body iron stores (mg/kg BW) ‡ . |
| Study 2: Daily* | 8:00 am, d1 | NA | NA | 0.6 (0.5-8.9) | 16.2 (13.5-23.0) | 4.4 (1.7) | 3.5 (2.7) |
| 8:00 am, d2 | 22.9 (10.5-49.4) | 13.8 (6.3-29.6) | 0.8 (0.4-6.1) | 15.5 (7.2-30.0) | 5.1 (1.3) | 2.7 (2.1) | |
| 8:00 am, d3 | 14.6 (7.2-28.3)§ | 8.8 (4.6-17.0)§ | 1.5 (0.3-8.5)‖ | 26.7 (11.6-57.5)¶ | 5 (1.5) | 4.7 (2.3)# | |
| 8:00 am, d15 | NA | NA | ND | 16.9 (7.3-34.0) | 5.1 (1.4) | 3.0 (1.7) | |
| Study 3: Twice daily* | 10:00 am, d1 | 17.1 (8.5-37.3) | 10.2 (5.1-22.4) | 0.9 (0.3-3.7) | 13.6 (7.1-32.0) | 4.9 (1.1) | 2.3 (2.2) |
| 4:00 pm, d2 | 12.5 (6.3-19.2)** | 7.5 (3.8-11.5)** | 4.1 (0.5-10.7)†† | 15.9 (6.1-37.5)‡‡ | 5.2 (1.3) | 2.5 (2.4) | |
| 8:00 am, d3 | 9.9 (4.4-16.3)** | 5.9 (2.6-9.8)** | 6.3 (1.3-14.1)††, § | 32.2 (19.3-57.8)a | 5.1 (1.4) | 5.2 (1.6)†† | |
| 8:00 am, d15 | NA | NA | ND | 16.4 (8.4-53.1) | 4.6 (0.9) | 3.2 (2.2) | |
BW, body weight; NA, not applicable; ND, not determined; PF, plasma ferritin; PHep, plasma hepcidin; sTfR, soluble transferrin receptor.
Studies 2 and 3 are two distinct studies conducted with either daily or twice-daily administration of 60-mg supplements.
In study 2, doses are given at 08:00 pm; in study 3, doses are given at 10:00 am and 5:00 pm to fasting subjects. All administrations were given to fasting subjects immediately after iron status determination.
Geometric means (range).
Means (SD). All doses 60 mg Fe as FeSO4, daily study, n = 16; twice-daily study, n = 13.
Different from d1 (paired Student t test, P < .01).
Different from d1, d2 (P < .05).
Different from d1, d2, and d16 (P < .01).
Different from d1, d2, and d16 (P < .05).
Different from other time points (P < .05).
Different from 10:00 am d1 (P < .01).
Different from preceding time point (P < .05).
¶¶Different from daily study 8:00 am d2 (P < .05).
aDifferent from all other time points (P < .001).