Table 3.
Methods and main findings in studies on the use of Fe and Zn biofortified foods in gut microbiota modulation.
| Reference | Experimental Groups | Method of Evaluation of the Gut Microbiota | Microbial Activity |
|---|---|---|---|
| Zn-biofortified food | |||
| Reed et al., 2018 [31] | CZn: Standard wheat (75% wheat-based diet; 32.8 ± 0.17 µg Zn/g) BZn: Zn biofortified wheat (75% Zn wheat-based diet; 46.5 ± 0.99 µg Zn/g) |
16S rRNA gene sequencing | Change in β-diversity between the CZn and BZn groups. ↔ no difference in abundance between Firmicutes, Actinobacteria, and Proteobacteria phyla according taxon-based analysis; ↔ no differences between groups at the genus level, according taxon-based analysis. LEfSe method: ↑ Lactobacillus reuteri and members of the Dorea, Clostridiales, Ruminococcus and Lachnospiraceae family in BZn group. |
| Fe-biofortified foods | |||
| Reed et al., 2017 [30] | SFe: Fe standard, 34.6% cream seeded carioca bean based diet (33.7 ± 0.80 μg Fe/g) BFe: Fe biofortified bean, 34.6% cream seeded carioca bean based diet (48.7 ± 1.50 μg Fe/g) |
16S rRNA gene sequencing | No change in β-diversity between the BFe and SFe groups; no difference in α-diversity between groups. ↑ Elusimicrobioa and Euryarchaeota phyla; ↑ Dehalobacteriaceae and Enterococcaceae family; ↑ unclassified Dehalobacteriaceae genus in the BFe group. ↓ Elusimicrobiaceae, Methanobacteriaceae, and Methanomassiliicoccaceae family; ↓ unclassified Elusimicrobiaceae, Methanobrevibacter, vadinCA11, and Enterococcus genus in the BFe group; LEfSe method: ↑ Proteobacteria and Firmicutes; ↓ Elusimicrobiota and Euryarchaeota at phylum level; ↑ Campylobacterales; ↓ Enterobacteriales, Elusimicrobiales, Bacteroidales and E2 at order level; ↑ Helicobacteraceae, Dehalobacteriaceae, and Streptococcaceae; ↓ Enterobacteriaceae, Enterococcaceae, Elusimicrobiaceae, Coriobacteriaceae, Methanomassiliicoccaceae, and Methanobacteriaceae at family level; ↑ Helicobacter, Ruminococcus, Coprococcus, and Streptococcus; ↓ Lachnospira, Enterococcus, vadinCA11, Methanobacterium, and Methanobrevibacter at genus level; ↑ OTUs enriched Faecalibacterium prausnitzii, Barnesiella viscericola, Enterococcus cecorum, and vadinCA11 in the BFe group. |
| Dias et al., 2018 [15] | SC: Fe-standard carioca bean-based diet, 42% BRS Perola bean-based diet (40.47 ± 1.84 μg Fe/g) BC: Fe-biofortified carioca bean-based diet, 42% BRS Cometa bean (47.04 ± 1.52 μg Fe/g) |
16S rRNA gene sequencing | Change in β-diversity between the BFe and SFe groups; no difference in α-diversity between groups; ↔ no significant differences between groups at the genus level; LEfSe method: Predominance of SCFA-producing Firmicutes in BC group; ↑ Eggerthella lenta and Clostridium piliforme; members of the Coriobacteriaceae, Dehalobacteriaceae and Lachnospiraceae in the BC group. |
| Dias et al., 2019 [29] | Non-injected 18 MΩH2O Inulin (40 mg/mL) Perola bean extract (Fe standard carioca bean, 3.2 ± 1.5 μg Fe/g) Cometa bean extract (Fe biofortified carioca bean, 1.8 ± 1.1 μg Fe/g) * Esteio bean extract (Fe standard black bean, 1.1 ± 0.6 μg Fe/g) * SMN 39 bean extract (Fe biofortified black bean, 2.2 ± 0.7 μg Fe/g) * Artico bean extract (Fe standard white bean,) * 6.0 ± 1.1 μg Fe/g |
PCR amplification of bacterial 16S rDNA for Lactobacillus, Bifidobacterium, Clostridium and E. coli | ↓ relative abundance of Bifidobacterium in biofortified carioca bean extract compared to standard; ↓ relative abundance of E. coli in biofortified carioca bean extract compared to standard; ↑ relative abundance of Lactobacillus in biofortified black bean extract compared to standard; ↑ relative abundance of Clostridium and E. coli in biofortified black bean extract compared to standard; ↔ relative abundance of Lactobacillus and Clostridium in biofortified carioca bean extract compared to standard; ↔ relative abundance of Bifidobacterium in biofortified black bean extract compared to standard. |
| Beasley et al., 2020 [28] | 1st experiment: NI: non-injected H2O: 18 MΩH2O Fe: Fe solution (1 mg/mL) Fe-EDTA: Fe-EDTA solution (77 μM Fe) Fe-NA: Fe-Nicotinamine solution (1.6 mM) C WF: Control wheat flour extract * (0.91 μg Fe/g of extract) B WF: Fe biofortified wheat flour extract * (0.82 μg Fe/g of extract) * 50 mg/mL 2nd experiment: Control: Fe-standard wheat, 80% wheat based diet (25.9 ± 0.12 μg Fe/g) Biofortified: Fe-biofortified wheat, 80% Fe wheat-based diet (28.9 ± 0.13 μg Fe/g) |
1st experiment: PCR amplification of bacterial 16S rDNA for Lactobacillus, Bifidobacterium, Escherichia and Clostridium 2nd experiment: 16S rRNA gene sequencing |
1st experiment: ↔ relative abundance of Bifidobacterium, Lactobacillus, Escherichia and Clostridium in biofortified wheat flour extract compared to the Control. 2nd experiment: Change in β-diversity and α-diversity between the Control and Biofortified groups; ↑ 1.9-fold the proportion of Actinobacteria; ↓ 1.2- and 2.0-fold, respectively, the proportion of Firmicutes and Proteobacteria in ‘Biofortified’ relative to ‘Control’ group at phyla level; ↑ 1.9- and 1.5-fold, respectively, the proportion of Bifidobacterium and Lactobacillus; ↑ abundance of Enterococcus; ↓ proportion of Streptococcus (1.7-fold), Coprococcus (1.4-fold), Ruminococcus (1.2-fold) Faecalibacterium (2-fold), and Escherichia (2-fold); ↓ Dorea abundance in ‘Biofortified’ relative to ‘Control’ group at genera level; ↓ 1.7-fold the proportion of Lachnospiraceae and ↑ abundance of Enterococcaceae families in ‘Biofortified’ relative to ‘Control’ group. |
↔ no change; ↑ increased; ↓ reduced; LEfSe: linear discriminant analysis effect size.