TABLE 1.
Overview of studies included in the review1
| Author/year | Country/subjects | Baseline iron status (ferritin) | Design/blinding | Iron compound | Prebiotic, dose, frequency, duration, and delivery method | Effects on iron absorption6 |
|---|---|---|---|---|---|---|
| Coudray et al., 1997 (25) | Francen = 9Healthy young menAge: not reported | Not reported | Metabolic mineral balance study, crossover design, blinding not reported | Dietary iron | Inulin or sugar beet fiber, 40 g/d, 28 d, incorporated into bread (60%) and liquid foods (40%) | ↔ |
| Behall et al., 1987 (41) | USAn = 11Healthy menAge: 23–62 y | 49 ± 14 μg/L2 | Metabolic mineral balance study, crossover design, blinding not reported | Dietary iron | Na-carboxymethylcellulose, locust bean gum, or karaya gum, 7.5 g fiber per 1000 cal/d, 4 wk each, in baked muffins or fruit gel | ↔ |
| Weinborn et al., 2017 (42) | Chilen = 24Healthy womenAge: 35–45 y | Prebiotic group: 20.1 ± 8.4 μg/L2Control group: 16.9 ± 9.8 μg/L2 | Radioactive Fe absorption study, subjects randomly assigned in 2 groups: prebiotic and control, blinding not reported | 3 mg Fe as heme Fe3 mg nonheme Fe as FeSO4 | Mixture containing inulin, polydextrose, arabic gum, and guar gum, 2 g/d, 12 d, in a yogurt | Heme iron ↑Nonheme iron ↔ |
| van den Heuvel et al., 1998 (43) | The Netherlandsn = 12Healthy menAge: 20–30 y | Not reported | Double stable-isotopeTechnique (oral and intravenous), randomized crossover, double-blind | Orally:37 mg Fe as FeSO4 divided in 21 meals, consumed with prebioticsIntravenous:1 mg Fe as FeSO4 | Inulin, FOS, or GOS, 15 g/d, 5 g per meal, 21 d each, with 100 mL orange juice | ↔ |
| Petry et al., 2012 (36) | Switzerlandn = 32Nonanemic iron-depleted womenAge: 18–40 y | 12.5 (7.1, 22.8) μg/L3 | Stable isotope study, randomized crossover, double-blind | 4 mg Fe as FeSO4, consumed 1 h after inulin or maltodextrin (control) consumption | Inulin or control (maltodextrin), 3 times per day (20 g/d total), 4 wk, dissolved in water and consumed with main meals | ↔ |
| Paganini et al., 2017 (38) | Kenyan = 50Mostly anemic infantsAge: 6–14 mo | Prebiotic group: 19.5 (13.0–39.1) μg/L4Control group: 15.1 (9.8–25.5) μg/L4 | Stable isotope study, randomized, single-blind | 5 mg Fe as FeFum + NaFeEDTA5 mg Fe as FeSO4; consumed with prebiotic in prebiotic group | GOS, 7.5 g/d, 3 wk, in a maize porridge fortified with a micronutrient powder | FeFum + NaFeEDTA ↑FeSO4 ↔ |
| Mikulic et al., 2021 (39) | Kenyan = 23Partly anemic infantsAge: 6–14 mo | 22.5 (9.7–52.1) μg/L5 | Stable isotope study, randomized, crossover, single-blind | 5 mg Fe as FeFum + NaFeEDTA5 mg Fe as FeSO4, consumed with and without GOS | GOS, 7.5 g/d, single dose, in a maize porridge fortified with a micronutrient powder | FeFum + NaFeEDTA ↔FeSO4↔ |
| Jeroense et al., 2019 (part 1) (35) | Switzerlandn = 34Nonanemic, iron-depleted womenAge: 18–45 y | 16.4 (11.3–30.8 μg/L4 | Stable isotope study, randomized, crossover, single-blind | 14 mg Fe as FeFum | GOS, 15 g, as single dose, given fasted with 200 mL water only or with a bread-based meal | ↑ |
| Jeroense et al., 2019 (part 2) (35) | Switzerlandn = 34Nonanemic, iron-depleted womenAge: 18–45 y | 16.4 (11.3–30.8) μg/L4 | Stable isotope study, randomized, crossover, single-blind | 14 mg Fe as FeFum, consumed with or without GOS | GOS, 15 g/d, 4 wk daily consumption, on day of isotope administration given fasted with 200 mL water and a bread-based meal | ↔ |
| Jeroense et al., 2019 (part 3) (35) | Switzerlandn = 34Nonanemic, iron-depleted womenAge: 18–45 y | 16.4 (11.3–30.8) μg/L4 | Stable isotope study, randomized, crossover, single-blind | 14 mg Fe as FeSO4, without GOS before and with GOS after the intervention | GOS, 15 g/d, 4 wk daily consumption + single dose, given fasted with 200 mL water in a bread-based meal | ↔ |
| Jeroense et al., 2020 (37) | Switzerlandn = 46Nonanemic, iron-depleted womenAge: 18–45 y | 17.1 (11.4–25.3) μg/L4 | Stable isotope study, randomized, crossover, single-blind | 14 mg Fe as FeFum14 mg Fe as FeSO414 mg Fe as FePP | GOS, 3.5, 7, or 15 g, single dose, given fasted with 200 mL water | 3.5 g GOS FeFum ↔7 g GOS FeFum ↑15 g GOS FeSO4 ↔15 g GOS FePP ↔ |
| Giorgetti et al., 2022 (44) | Switzerlandn = 30Nonanemic, iron-depleted womenAge: 18–45 y | 12.9 (10.0–19.9 μg/L4 | Stable isotope study, randomized, crossover, single blind | 100 mg Fe as FeFum | GOS, FOS, and acacia gum, 15 g, single dose, given fasted with 200 mL water | GOS ↑FOS ↑Acacia gum ↔ |
| Husmann et al., 2022 (40) | Switzerlandn = 11Nonanemic, iron-depleted womenAge: 18–45 y | 15.2 (12.6–21.2) μg/L4 | Stable isotope study, randomized, crossover, single blind | 14 mg Fe as FeFum | GOS, 15 g, single dose, given fasted with 200 mL water | ↔ |
1
FeFum, ferrous fumarate; FePP, ferric pyrophosphate; FeSO4, ferrous sulfate; FOS, fructo-oligosaccharides; GOS, galacto-oligosaccharides; NaFeEDTA, sodium iron ethylenediaminetetraacetate.
2
Mean ± SD.
3
Geometric mean (95% CI).
4
Median (IQR).
5
Geometric means (−SD, +SD).
6
↑ = statistically significant increase, ↔ = no statistically significant difference.